Endangered and Threatened Wildlife and Plants; Threatened Species Status With Section 4(d) Rule for Cactus Ferruginous Pygmy-Owl

DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R2-ES-2021-0098; FF09E21000 FXES1111090FEDR 234]

RIN 1018-BF25

Endangered and Threatened Wildlife and Plants; Threatened Species Status With Section 4(d) Rule for Cactus Ferruginous Pygmy-Owl

AGENCY:

Fish and Wildlife Service, Interior.

ACTION:

Final rule.

SUMMARY:

We, the U.S. Fish and Wildlife Service (Service), determine threatened species status under the Endangered Species Act of 1973 (Act), as amended, for the cactus ferruginous pygmy-owl (

Glaucidium brasilianum cactorum

), a bird subspecies found in Mexico, southern Arizona, and southern Texas. This rule adds the subspecies to the List of Endangered and Threatened Wildlife. We also finalize a rule under the authority of section 4(d) of the Act that provides measures that are necessary and advisable to provide for the conservation of this subspecies. We concluded that designation of critical habitat is prudent and determinable at this time. Critical habitat will be proposed in a separate rule-making.

DATES:

This rule is effective August 21, 2023.

ADDRESSES:

This final rule is available on the internet at

https://www.regulations.gov.

Comments and materials we received, as well as supporting documentation we used in preparing this rule, are available for public inspection at

https://www.regulations.gov

at Docket No. FWS-R2-ES-2021-0098.

FOR FURTHER INFORMATION CONTACT:

Heather Whitlaw, Field Supervisor, U.S. Fish and Wildlife Service, Arizona Ecological Services Field Office, 9828 N 31st Ave., Phoenix, AZ 85051; telephone 602-242-0210. Individuals in the United States who are deaf, deafblind, hard of hearing, or have a speech disability may dial 711 (TTY, TDD, or TeleBraille) to access telecommunications relay services. Individuals outside the United States should use the relay services offered within their country to make international calls to the point-of-contact in the United States.

SUPPLEMENTARY INFORMATION:

Executive Summary

Why we need to publish a rule.

Under the Act, a species, subspecies, or distinct vertebrate population segment warrants listing if it meets the definition of an endangered species (in danger of extinction throughout all or a significant portion of its range) or a threatened species (likely to become endangered within the foreseeable future throughout all or a significant portion of its range). If we determine that a species warrants listing, we must list the species promptly and designate the species' critical habitat to the maximum extent prudent and determinable. We have determined that the cactus ferruginous pygmy-owl meets the definition of a threatened subspecies; therefore, we are listing it as such. We have determined that the designation of critical habitat for the cactus ferruginous pygmy-owl is prudent and determinable, and we will propose designation in a separate rule. Listing a species as an endangered or threatened species can be completed only by issuing a rule through the Administrative Procedure Act rulemaking process (5 U.S.C. 551

et seq.

).

What this document does.

This rule lists the cactus ferruginous pygmy-owl as a threatened subspecies under the Act and adds it to the List of Endangered and Threatened Wildlife. This rule also finalizes a rule issued under section 4(d) of the Act (hereafter, referred to as a “4(d) rule”).

The basis for our action.

Under the Act, we may determine that a species is an endangered or threatened species because of any of five factors: (A) The present or threatened destruction, modification, or curtailment of its habitat or range; (B) overutilization for commercial, recreational, scientific, or educational purposes; (C) disease or predation; (D) the inadequacy of existing regulatory mechanisms; or (E) other natural or manmade factors affecting its continued existence. We have determined that threats to the cactus ferruginous pygmy-owl include: (1) Habitat loss and fragmentation from urbanization, invasive species, and agricultural or forest production; and (2) climate change (effects from current and future changes in climate) and climate conditions (effects from current and past climate), resulting in hotter, more arid conditions throughout much of the subspecies' geographic range. The 4(d) rule would generally prohibit the same activities as prohibited for an endangered species but would allow exemptions for specific types of education and outreach activities already permitted under a Migratory Bird Treaty Act permit, surveying and monitoring conducted in Arizona under a state scientific activity permit issued by the state, and habitat restoration and enhancement activities that improve habitat conditions for the cactus ferruginous pygmy-owl.

Section 4(a)(3) of the Act requires the Secretary of the Interior (Secretary) to designate critical habitat concurrent with listing to the maximum extent prudent and determinable. Section 3(5)(A) of the Act defines critical habitat as (i) the specific areas within the geographical area occupied by the species, at the time it is listed, on which are found those physical or biological features (I) essential to the conservation of the species and (II) which may require special management considerations or protections; and (ii) specific areas outside the geographical area occupied by the species at the time it is listed, upon a determination by the Secretary that such areas are essential for the conservation of the species. Section 4(b)(2) of the Act states that the Secretary must make the designation on the basis of the best scientific data available and after taking into consideration the economic impact, the impact on national security, and any other relevant impacts of specifying any particular area as critical habitat. As stated in the proposed listing rule (86 FR 72547, December 22, 2021), we have determined that the designation of critical habitat for the cactus ferruginous pygmy-owl is prudent and will be proposed in a separate rule.

Previous Federal Actions

As described in Previous Federal Actions of our proposed listing rule for the cactus ferruginous pygmy-owl (86 FR 72547, December 22, 2021), we received a petition dated March 15, 2007, from the Center for Biological Diversity and Defenders of Wildlife (CBD, DOW; petitioners) requesting that we list the cactus ferruginous pygmy-owl as an endangered or threatened species under the Act (CBD and DOW 2007, entire). On October 5, 2011, we published in the

Federal Register

(76 FR 61856) a 12-month finding on the petition to list the pygmy-owl as endangered or threatened. Using the currently accepted taxonomic classification of the pygmy-owl (

Glaucidium brasilianum cactorum

), we found that listing the pygmy-owl was not warranted throughout all or a significant portion of its range, including the petitioned and other potential distinct population segment (DPS) configurations. We were litigated on this decision (Case 4:12-cv-00627-CKJ), and the court found in favor of the

plaintiffs and remanded the 2011 12-month finding on the 2007 petition to list the pygmy-owl (Case 4:14-cv-02506-RM). Under a court settlement, we developed a new 12-month finding and published our proposed rule to list the pygmy-owl on December 22, 2021 (86 FR 72547).

Peer Review

A species status assessment (SSA) team prepared an SSA report for the cactus ferruginous pygmy-owl. The SSA team was composed of Service biologists, in consultation with other species and subject-matter experts. The SSA report represents a compilation of the best scientific and commercial data available concerning the status of the subspecies, including the impacts of past, present, and future factors (both negative and beneficial) affecting the subspecies.

In accordance with our joint policy on peer review published in the

Federal Register

on July 1, 1994 (59 FR 34270), and our August 22, 2016, memorandum updating and clarifying the role of peer review of listing actions under the Act, we solicited independent scientific review of the information contained in the SSA report. As discussed in the proposed rule, we sent the SSA report to five independent peer reviewers and received three responses. The peer reviews can be found at

https://regulations.gov.

We also sent the SSA report to 13 partners, including Tribes and scientists with expertise in land management, pygmy-owl and raptor ecology, and climate science, for review. We received review from 11 partners, including State and Federal agencies, universities, and nonprofit organizations. In preparing the proposed rule, we incorporated the results of these reviews, as appropriate, into the SSA report, which was the foundation for the proposed rule and this final rule.

Summary of Changes From the Proposed Rule

Since the publication of the December 22, 2021, proposed rule to list the cactus ferruginous pygmy-owl as threatened with a 4(d) rule (86 FR 72547), we have made the following changes:

(1) Per requests from commenters, we have revised the provisions of the 4(d) rule. We updated and clarified our description of the habitat restoration and enhancement exception to clarify that this exception does not include vegetation management along roadways or fuels management that includes the removal of trees and large shrubs. We also provided additional clarity and guidance on what types of projects would be excepted under the 4(d) rule and which would require coordination with and approval from the Service. These changes included additional clarification regarding conditions under which prescribed fire may be excepted under the 4(d) rule and specific guidance on how to coordinate with us prior to habitat restoration and enhancement projects to ensure that projects qualify for exception under the 4(d) rule.

(2) In the preamble, we now include a more detailed discussion of the DPS analysis we undertook, including a description of any pertinent new information we have received since our 2011 12-month finding (76 FR 61856, October 5, 2011).

(3) Based upon new reports we received from the Arizona Game and Fish Department during the comment period, we updated the biological information for the subspecies related to surveys, distribution, occupancy, and genetic differentiation (AGFD 2021b, pers. comm.; Cobbold et al. 2021, entire; Cobbold et al. 2022a, entire; Cobbold et al. 2022b, entire). This information did not alter any significant findings in the proposed rule.

(4) A number of commenters provided us with additional references to consider as we finalized this rule. We considered these references and other references we found while responding to public comments and have incorporated them and any associated information in the final rule and SSA report as appropriate. See the Summary of New Information Since the 2011 12-Month Finding section below for an explanation of where these new references are included in issues relevant to our finding and determination.

(5) We added a summary of the new information and changes that have occurred since our 2011 12-month finding to clarify the factors that contributed to a different determination in this final listing rule. This summary is found in Summary of New Information Since the 2011 12-Month Finding, below.

(6) In response to a comment received during the public comment period, we completed additional analysis on the effects of certain land uses in Texas and Arizona over the past decade (2010-2020) on pygmy-owl habitat using additional sources of information to the source used by the commenter. This further analysis can be found in appendix 6 of the SSA report (Service 2022a, appendix 6).

Summary of New Information Since the 2011 12-Month Finding

This final listing rule results in a different finding than our 2011 12-month finding. This change in finding is based on an additional decade of threats and land-use changes, as well as climate change, acting on the landscape within the range of the pygmy-owl. We also used a different approach in assessing the status of the pygmy-owl throughout its range. We developed a species status assessment for the pygmy-owl using the best available information and a team of experts, including subject-matter experts, representing a range of agencies, Tribal entities, and conservation partners, supported by new spatial data and modeling developed subsequent to our 2011 12-month finding (76 FR 61856, October 5, 2011). Below we summarize the new information available since 2011 upon which our 2021 proposed listing rule (86 FR 72547, December 22, 2021) was based. We have also updated our discussion of the DPS finding to include information subsequent to our 2011 12-month finding (see

Distinct Vertebrate Population Segment,

below).

Taxonomic Classification

Additional genetic sampling was conducted in Mexico by the Arizona Game and Fish Department (AGFD) (Cobbold et al. 2022b, entire). While these additional data add to the baseline information we used to evaluate the status of the pygmy-owl, these results did not change our finding that we lack sufficient information to adopt the proposed taxonomic classification (change taxonomic classification to

Glaucidium ridgwayi cactorum

with associated change in distribution) described by Proudfoot et al. (2006a, entire; 2006b, entire) and discussed in the 2011 12-month finding (76 FR 61856, October 5, 2011). Therefore, no change to the taxonomic classification of the pygmy-owl has occurred since our 2011 12-month finding.

Rangewide Distribution

The taxonomic classification of the pygmy-owl did not change; thus, the general geographic distribution of the pygmy-owl did not change and is the same as described in the 2011 12-month finding (76 FR 61856, October 5, 2011). However, the analysis in our current finding divided the overall range of the pygmy-owl into five separate analysis units. Using this smaller scale analysis, we were able to discuss the condition of pygmy-owl populations and their habitat within each analysis unit, which is a finer resolution analysis than we

used in 2011. This more detailed analysis can be found in the SSA report (Service 2022a, entire), which includes a detailed description of each analysis unit. We also accessed additional pygmy-owl locations across the range of the pygmy-owl that we did not use in 2011 via the Global Biodiversity Information Facility, which included location data from such sources as eBird, iNaturalist, and museum specimens (GBIF 2020, unpaginated).

Climate Change

The decade that passed between our 2011 12-month finding (76 FR 61856, October 5, 2011) and our proposed listing rule (86 FR 72547, December 22, 2021) has been characterized by ongoing climate impacts to pygmy-owl populations and their habitats (Bagne and Finch 2012, entire; Coe et al. 2012, entire; Jiang and Yang 2012, entire; Romero-Lankao, et al. 2014, p. 1443; Melillo et al. 2014, entire; USGCRP 2018, chapters 23 and 25). Impacts resulting from climate change such as ongoing drought (habitat and prey impacts), increased temperatures (decreased productivity), reduced vegetation health and associated impacts to pygmy-owl prey availability, and increased fire occurrence (habitat and prey impacts) have resulted in negative effects to pygmy-owl abundance and distribution, as well as in loss of habitat and increased habitat fragmentation (Melillo et al. 2014, entire; Vermote et al. 2014, unpaginated; Cook et al. 2015, p. 6; Easterling et al. 2017, pp. 207-230; USGCRP 2018, chapters 23 and 25; Gonzalez et al. 2018, entire; Breshears et al. 2018, p. 1; Williams et al. 2020, p. 317, IPCC 2022, entire).

Enough time has passed since the early predictions of impacts of climate change that we have seen evidence of those predicted impacts on vegetation communities across the range of the pygmy-owl. Generally, these impacts have been in line with or worse than what was predicted. New climate models and projections and updated information in general were available for our analysis. These projections continue to predict impacts at the same or increasing levels upon the landscape in areas where the pygmy-owl occurs. This information is discussed in greater detail in

Climate Change and Climate Conditions,

below. Additionally, we included climate scientists in our peer and partner review of the climate section of the pygmy-owl SSA report, and they provided input and updated citations regarding our discussion of climate effects that are included in the SSA report and this final listing rule.

Rangewide Habitat Loss

With the exception of climate change, there is not a single threat leading to habitat loss across the range of the pygmy-owl. However, habitat loss is occurring across every portion of the range of the pygmy-owl. Each of the five analysis units is experiencing varying degrees of pygmy-owl habitat loss that, when considered together, result in rangewide habitat loss (Thomas et al. 2012, p. 43; Lyons et al. 2013, p. 8; Vo 2013, unpaginated; TDC 2019, entire; Texas Land Trends 2019, entire; Wied et al. 2020, entire; Mesa-Sierra et al. 2022, unpaginated; Burquez 2022, pers. comm.). The 2011 12-month finding did not assess local habitat impacts at the level of individual analysis units. These more specific descriptions of threats and impacts by analysis unit can be found in the SSA report (Service 2022a, appendix 5) and in

Summary of Current Condition of the Subspecies,

below.

Status in Arizona

As in 2011, pygmy-owls continue to be absent from Pinal County and around Tucson where they were found as recently as the early 2000s (Ingraldi 2020, pers. comm.). Additionally, based on survey efforts in 2020 and 2021, pygmy-owls can no longer be found reliably in Organ Pipe Cactus National Monument for the first time since records have been kept (Ingraldi 2020, pers. comm.; AGFD 2021b, pers. comm.). Personal communication with Tribal staff indicates that pygmy-owls continue to be found on the Tohono O'odham Nation, although comprehensive surveys have not been conducted and information on specific locations of pygmy-owls is not released by the Tohono O'odham Nation (Verwys 2020 and 2021, pers. comm.). Currently, the known abundance of owls is higher in Altar Valley than it was in 2011, likely due to increased survey and monitoring under the Pima County Multi-Species Conservation Plan and by the AGFD (Flesch 2018a, entire; Ingraldi 2020, pers. comm.; PCOSC 2021, entire). However, occupancy in the Altar Valley appears to be down in 2022, potentially in response to the dry winter of 2021-2022 and ongoing drought conditions (AGFD 2022, unpublished data; Service 2022b, unpublished data; NDMC 2022, unpaginated).

Threats related to climate change have increased, including fire (Inciweb 2022, unpaginated), invasive species, degraded vegetation condition, and reduced prey availability due to drought and impacted hydrology including the loss of surface and ground water (BOR 2021, entire; NDMC 2022, unpaginated). Development continues to impact habitat particularly in areas of northwest Tucson and Pinal County. While there is not a direct correlation between acres of pygmy-owl habitat lost and human population growth, it is reasonable to find that, as human population grows, the amount of native habitat lost or fragmented will increase. We looked at recent population growth and projections in Arizona as an indication for future urbanization (OEO 2018, unpaginated; U.S. Census Bureau 2021a, unpaginated; EBRC 2021, unpaginated). New, taller border walls have been constructed along all border areas occupied by pygmy-owls in Arizona (DHS 2020, unpaginated). As discussed in the SSA report, the impacts of this border infrastructure on pygmy-owls have not been studied but represent a potential barrier to pygmy-owl movements along and across the border.

We considered a new analysis of Arizona pygmy-owl occupancy (Flesch et al. 2017, entire). This report includes an analysis of factors contributing to pygmy-owl occupancy in Arizona, as well as factors to consider in designing and implementing pygmy-owl conservation actions. In addition, a climate change study that was published since our 2011 12-month finding predicts a reduction in saguaros (

Carnegiea gigantea

) in the Sonoran Desert (Thomas et al. 2012, p. 43). Saguaros are the key nesting substrate for pygmy-owls in the Sonoran Desert of Arizona.

Status in Texas

Threats to the pygmy-owl and pygmy-owl habitat from drought, as well as fire, freezes, and hurricanes (Harvey in 2017, Hanna in 2020, and Ida in 2021) have all continued in Texas over the past decade (EPA 2016, unpaginated; Bhatia et al. 2019, entire; Inciweb 2022, unpaginated; Bond 2022, unpaginated; NDMC 2022, unpaginated; NIFC 2022, unpaginated; NWS 2022, unpaginated). Many of these effects are the result of climate change (Romero-Lankao, et al. 2014, p. 1459; EPA 2016, unpaginated; Gonzalez et al. 2018, entire). Urbanization and agricultural development in both Texas and northeastern Mexico (Texas Land Trends 2019, entire; USGS 2022, unpaginated; Texas Comptroller 2020, unpaginated) have continued, likely resulting in increased isolation of the Texas population from those in Mexico. No recent surveying or monitoring has been conducted in Texas. However, given current habitat conditions as outlined in the SSA report, the declines in pygmy-owls and pygmy-owl habitat

documented in the 2011 12-month finding have likely continued, resulting in reduced abundance of pygmy-owls. For example, the Texas Parks and Wildlife Department recently changed the conservation status rank for ferruginous pygmy-owl in Texas from S3:vulnerable to S2:imperiled (TPWD 2022, unpaginated). In addition, the number and distribution of pygmy-owls in the Lower Rio Grande Valley has declined since 1988, likely due to the ongoing loss of riparian habitats along the Rio Grande (Leslie 2016, entire).

Status in Northern Sonora

Our understanding of the habitat needs for pygmy-owls in the Sonoran Desert has improved since 2011 as a result of ongoing research in northern Sonora (Flesch 2014, entire; Flesch et al. 2015, entire; Flesch 2017, entire; Flesch et al. 2017, entire; Cobbold et al. 2021, entire; Cobbold et al 2022a, entire). The abundance of pygmy-owls in northern Sonora has declined with increasing drought (Flesch et al. 2017, entire; Flesch 2021, entire). Abundance and densities of pygmy-owls are, in general, higher farther south in Sonora in thornscrub and tropical dry forests and lower in the northern part of northwest Mexico (Cobbold et al. 2021, entire; Cobbold et al. 2022a, entire). These data are consistent with previous findings (Flesch 2003, entire). Threats resulting in reduced vegetation condition and increased habitat fragmentation have been documented (Flesch 2014, entire; Flesch et al. 2015, entire; Flesch et al. 2017, entire; Flesch 2021, entire). In 2012, a climate change study was published predicting a reduction in saguaros in the Sonoran Desert (Thomas et al. 2012, p. 43). Saguaros are the key nesting substrate for pygmy-owls in the Sonoran Desert of northern Sonora. In addition, a retired Service biologist who led the Sonoran Joint Venture provided updated information on the status of land use and impacts to pygmy-owls in Sonora (Mesta 2020, pers. comm.).

Status in Remainder of Mexico

There are no recent pygmy-owl survey or monitoring data for the remainder of Mexico, so we continue to have no recent, verified data on abundance or occupancy. We used eBird, iNaturalist, and museum specimen records to get a general scope of occurrences in these areas, but did not use these records to estimate abundance (GBIF 2020, unpaginated; Johnston et al. 2021, p. 1266). Ten additional years of threats acting on these population groups have impacted the landscape and habitat of the pygmy-owl in these areas including extraction of natural resources, increases in invasive species, use of pesticides, and the effects of climate change such as drought and increased evapotranspiration (Enríquez and Vazquez-Perez 2017, p. 546, DataMexico 2021, unpaginated; Murray-Tortarolo 2021; entire; Mesa-Sierra et al. 2022, unpaginated). Specifically, habitat loss and fragmentation has increased since 2011 as a result of wood harvesting, agriculture, population growth and urbanization, and other land uses (CONAPO 2014, p. 25; Enríquez and Vazquez-Perez 2017, p. 546; DataMexico 2021, unpaginated; Burquez 2022, pers. comm.). Increases in hurricanes in northeastern Mexico (EPA 2016, entire) have resulted in impacts to pygmy-owl habitat. We also received additional information related to the status of the pygmy-owl in Mexico such as the lack of research and data, lack of land use planning and government oversight, other threats, establishment of preserve areas, and cultural significance (Enríquez and Vazquez-Perez 2017, p. 546; Enríquez 2021, pers. comm.).

Conservation Actions

Implementation of the Pima County Multi-Species Conservation Plan has resulted in additional surveys for pygmy-owls on lands controlled by Pima County in Arizona. Additional pygmy-owl habitat has been protected through conservation planning and habitat acquisition and protection as part of implementing this large, regional Pima County Habitat Conservation Plan (Pima County 2016, entire; Flesch 2018a, entire; PCOSC 2021, entire). Investigation of captive-breeding and release to establish new pygmy-owl population groups and to augment existing population groups has continued in Arizona (AGFD 2015, entire). The Altar Valley Watershed Plan has been developed and will contribute to the enhancement of pygmy-owl habitat in Altar Valley, Arizona (Altar Valley Watershed Working Group 2022, entire).

Factor A—The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range

We evaluated new information related to the effects of present and future climate change on vegetation on which the pygmy-owl depends (Bagne and Finch 2012, entire; Coe et al. 2012, entire; Jiang and Yang 2012, entire; Flesch 2014, pp. 113-116; Melillo et al. 2014, entire; Romero-Lankao, et al. 2014, p. 1443; Flesch et al. 2015, entire; Pearce-Higgins et al. 2015, entire; Deguines et al. 2017, entire; Flesch et al. 2017, entire; USGCRP 2018, chapters 23 and 25). The incidence of fires, particularly in Arizona and Texas, has increased since 2011 (Inciweb 2022, unpaginated). While there is not a direct correlation between acres of pygmy-owl habitat lost and human population growth, it is reasonable to find that, as human population grows, the amount of native habitat lost or fragmented will increase. We used updated population growth estimates in the SSA report and this final rule (Brinkhoff 2016, unpaginated; HHS 2017, unpaginated; OEO 2018, unpaginated; INEGI 2021, unpaginated; CONAPO 2014, p. 25; TDC 2019, entire; Pinal County 2019, p. 126; Gonzales 2020, unpaginated; DataMexico 2021, unpaginated; Service 2022a, chapter 7). We also looked at more recent information from Mexico related to habitat loss and fragmentation, which showed that land uses continue to impact pygmy-owl habitat and the occupancy and productivity of pygmy-owls (Enríquez and Vazquez-Perez 2017, p. 546; Flesch et al. 2017, entire). We have also included recent information on the effects of buffelgrass on the ecosystems and habitats used by pygmy-owls (Lyons et al. 2013, p. 8; Vo 2013, entire, Wied et al. 2020, p. 47; ASDM 2022, unpaginated). We also considered new information showing that pygmy-owl occupancy decreases in areas of increased roadway size, agricultural development, and other factors causing pygmy-owl habitat disturbance (Flesch 2017, p. 5; Flesch et al. 2017, entire; Flesch 2021, pp. 12-14).

Factor B—Overutilization for Commercial, Recreational, Scientific, or Educational Purposes

We have observed a recent increase in visitation by birders (2019 to present) to known pygmy-owl territories (Flesch 2018b, pers. comm., Vaughan 2019, pers. comm.), but we have not studied how that activity has affected occupancy and productivity. We also evaluated more recent information on the impacts of researchers on birds (Gibson et al. 2015, pp. 404-406; Herzog et al. 2020, p. 891).

Factor C—Disease or Predation

We are not aware of any additional information regarding the effects of disease and predation on pygmy-owls since what was included in our 2011 12-month finding.

Factor D—The Inadequacy of Existing Regulatory Mechanisms

Typically, work funded or implemented by Federal agencies complies with a number of environmental laws such as the National Environmental Policy Act and

the Endangered Species Act. However, under the Real ID Act, the U.S. Department of Homeland Security (DHS) waived environmental compliance for much of the border infrastructure work completed recently in Arizona and Texas (Fischer 2019, unpaginated; USCBP 2020, unpaginated). This work included the construction of taller border fencing with lights and associated access roads contributing to habitat loss and fragmentation.

Factor E—Other Natural or Manmade Factors Affecting the Species' Continued Existence

A new potential threat to pygmy-owls was identified subsequent to our 2011 12-month finding as reported in a study that documented pesticides in pygmy-owl feathers and blood (Arrona-Rivera et al. 2016, entire). We also evaluated new information related to climate and weather impacts on pygmy-owls that affect productivity in pygmy-owls as well as pygmy-owl prey species (Flesch 2014, pp. 113-116; Flesch et al. 2015, entire; Pearce-Higgins et al. 2015, entire; Deguines et al. 2017, entire; Flesch et al. 2017, entire). We considered a more recent publication on the potential for small population size to increase extinction risk and the types of information needed to model such risk (Benson et al. 2016, pp. 1-2, 8). During the development of the pygmy-owl SSA report, we sought peer and partner review specifically on our climate change analysis. The responses we received from climate experts were used to update our SSA report and are included in more detail in this final rule.

Additionally, we considered more recent information related to updated climate models, downscaled climate predictions, and information on drought (Bagne and Finch 2012, entire; Coe et al. 2012, entire; Jiang and Yang 2012, entire; Romero-Lankao, et al. 2014, p. 1443; Melillo et al. 2014, entire; Cook et al. 2015, p. 6; Wang et al. 2016, pp. 6-7; Dewes et al. 2017, p. 17; Easterling et al. 2017, entire; Diffenbaugh et al.

2

017, entire; Gonzalez et al. 2018, entire; Christensen et al. 2018, p. 5409; Breshears et al. 2018, p. 6; Williams et al. 2020, p. 317; Bradford et al. 2020, entire; BOR 2021, entire). Furthermore, additional IPCC reports have been published since 2011, as well as National Climate Assessments, and we have included these in our climate analysis related to this final rule and the pygmy-owl SSA report (IPCC 2014b, entire; Melillo et al. 2014, entire; USGCRP 2018, chapters 23 and 25; IPCC 2022, entire). We also have new information indicating that climate extremes may be more important than averages (Germain and Lutz 2020, entire) and further evidence that climate has become, and is projected to become, more extreme within the range of the pygmy-owl (Bagne and Finch 2012, entire; Cook et al. 2015, p. 6; Diffenbaugh et al. 2017, entire; Easterling et al. 2017, entire; BOR 2021, entire). Additionally, since our 2011 12-month finding, a climate change study was published predicting a reduction in saguaros in the Sonoran Desert (Thomas et al. 2012, p. 43). Saguaros are the key nesting substrate for pygmy-owls in the Sonoran Desert.

Overall Status and Needs of Pygmy-Owls

Subsequent to our 2011 12-month finding, the IUCN published a Red List Update for the ferruginous pygmy-owl

(Glaucidium brasilianum)

and, although the status remained the same as the 2009 Red List status (Least Concern), the Update acknowledged rangewide declines in the ferruginous pygmy-owl (BirdLife International 2016, unpaginated). We also reviewed and incorporated the updated Birds of North America ferruginous pygmy-owl account (now Birds of the World) (Proudfoot et al. 2020, entire). Additionally, new information has been published further supporting the importance of woodland vegetation and large, unfragmented habitat patches in the Sonoran Desert (Flesch et al. 2015, entire).

Additional Sources of Information

The following includes a list of information sources that were included subsequent to the proposed rule: AdaptWest Project 2015, unpaginated; AdaptWest Project 2022, unpaginated; Altar Valley Watershed Working Group 2022, entire; AGFD 2021b, pers. comm.; AGFD 2022, unpublished data; ASDM 2022, unpaginated; Arrona-Rivera et al. 2016, entire; Bhatia et al. 2019, entire; BirdLife International 2016, unpaginated; Blackie et al. 2014, entire; Bond 2022, unpaginated; Bradford et al. 2020, entire; Breshears et al. 2018, entire; Buffelgrass Working Group 2008, entire; BOR 1947, unpaginated; BOR 2021, entire; Burquez 2022, pers. comm.; Burquez and Martinez-Yrizar 1997, entire; Christensen et al. 2018, entire; Cobbold et al. 2021, entire; Cobbold et al. 2022a, entire; Cobbold et al. 2022b, entire; Cook et al. 2001, entire; Deguines et al. 2017, entire; Dewes et al. 2017, entire; Diffenbaugh et al. 2017, entire; Easterling et al. 2017, entire; Enríquez et al. 2017, entire; Flesch 2003, entire; Flesch 2014, entire; Flesch 2017, entire; Flesch 2018a, entire; Flesch 2018b, pers. comm., Flesch 2021, entire; Flesch et al. 2010, entire; Germain and Lutz 2020, entire; Gonzalez et al. 2018, entire; Gonzales 2020, unpaginated; Gornish and Howery 2019, entire; Herzog et al. 2020, entire; Inciweb 2022, unpaginated; IPCC 2014b, entire; IPCC 2022, entire; Johnson et al. 2004, entire; Johnston et al. 2021, entire; Keith 2007, entire; Lesli 2016, entire; Marris 2006, entire; Mays 1996, entire; Melillo et al. 2014, entire; Meltz and Copeland 2007, entire; Mesa-Sierra et al. 2022, entire; Mesta 2020, pers. comm.; Murray-Tortarolo 2021, entire; NDMC 2022, unpaginated; NIFC 2022, unpaginated; INEGI 2021, unpaginated; NWS 2022, unpaginated; Pearce-Higgins et al. 2015, unpaginated; PCOSC 2021, entire; Pinal County 2019, entire; Romero-Lankao et al. 2014, entire; Texas Comptroller 2020, unpaginated; TDC 2019, entire; Texas Land Trends 2019, entire; TPWD 2022, unpaginated; U.S. Census Bureau 2021b, unpaginated; DHS 2020, unpaginated; U.S. NDMC 2022, unpaginated; EPA 2016, unpaginated; Service 2022b, unpaginated; USGCRP 2018, entire; USGS 2022, unpaginated; EBRC 2021, unpaginated; Valdez et al. 2006, entire; Vaughan 2019, pers. comm.; Vermote et al. 2014, unpaginated; Verwys 2020, pers. comm.; Verwys 2021, pers. comm.; Walker and Pavlakovish-Kochi 2003, entire; Wang et al. 2016, entire; Wied et al. 2020, entire.

I. Final Listing Determination

Background

A thorough review of the taxonomy, life history, and ecology of the cactus ferruginous pygmy-owl is presented in the SSA report. We summarize this information here.

The cactus ferruginous pygmy-owl is a diurnal, nonmigratory subspecies of ferruginous pygmy-owl and is found from central Arizona south to Michoacán, Mexico, in the west and from south Texas to Tamaulipas and Nuevo Leon, Mexico, in the east. Pygmy-owls eat a variety of prey including birds, insects, lizards, and small mammals, with the relative importance of prey type varying throughout the year.

The pygmy-owl is a small bird, approximately 17 centimeters (cm) (6.7 inches (in)) long. Generally, male pygmy-owls average 58 grams (g) to 66 g (2.0 to 2.3 ounces (oz)) and females average 70 g to 75 g (2.4 to 2.6 oz). The pygmy-owl is reddish brown overall, with a cream-colored belly streaked with reddish brown. The crown is lightly streaked, and a pair of dark

brown or black spots outlined in white occurs on the nape, suggesting eyes (Oberholser 1974, p. 451). The species lacks obvious ear tufts (Santillan et al. 2008, p. 154), and the eyes are yellow. The tail is relatively long for an owl and is reddish brown in color, with darker brown bars. Males have pale bands between the dark bars on the tail, while females have darker reddish bands between the dark bars.

Cactus ferruginous pygmy-owls are secondary cavity nesters, nesting in cavities of trees and columnar cacti, with nesting substrate varying throughout its range. Pygmy-owls can breed in their first year and typically mate for life, with both sexes breeding annually. Clutch size can vary from two to seven eggs with the female incubating the eggs for 28 days (Johnsgard 1988, p. 162; Proudfoot and Johnson 2000, p. 11). Fledglings disperse from their natal sites about 8 weeks after they fledge (Flesch and Steidl 2007, p. 36). Pygmy-owls live on average 3 to 5 years but have been documented to live 7 to 9 years in the wild (Proudfoot 2009, pers. comm.) and 10 years in captivity (Abbate 2009, pers. comm.).

Pygmy-owls are found in a variety of vegetation communities, including Sonoran desertscrub and semidesert grasslands in Arizona and northern Sonora, thornscrub and tropical dry forests in southern Sonora south to Michoacán, Tamaulipan brushland in northeastern Mexico, and live oak forest in Texas. At a finer scale, the pygmy-owl is a creature of edges found in semi-open areas of thorny scrub and woodlands in association with giant cacti and in scattered patches of woodlands in open landscapes, such as tropical dry forests and riparian communities along ephemeral, intermittent, and perennial drainages (König et al. 1999, p. 373). It is often found at the edges of riparian and xeroriparian drainages and even habitat edges created by villages, towns, and cities (Abbate et al. 1999, pp. 14-23; Proudfoot and Johnson 2000, p. 5).

The taxonomy of

Glaucidium

is complicated and has been the subject of much discussion and investigation. Following delisting of the pygmy-owl in 2006 (71 FR 19452, April 14, 2006), we were petitioned to relist the pygmy-owl (CBD and DOW 2007, entire). The petitioners requested a revised taxonomic consideration for the pygmy-owl based on Proudfoot et al. (2006a, p. 9; 2006b, p. 946) and König et al. (1999, pp. 160, 370-373), classifying the northern portion of

Glaucidium brasilianum'

s range as an entirely separate species,

G. ridgwayi,

and recognizing two subspecies of

G. ridgwayi: G. r. cactorum

in western Mexico and Arizona and

G. r. ridgwayi

in eastern Mexico and Texas. Other recent studies proposing or supporting the change to

G. ridgwayi

for the northern portion of

G. brasilianum'

s range have been published in the past 20 years (Navarro-Sigüenza and Peterson 2004, p. 5; Wink et al. 2008, pp. 42-63; Enríquez et al. 2017, p. 15).

As we evaluated the cactus ferruginous pygmy-owl's current status, we found that, although there is genetic differentiation at the far ends of the pygmy-owl's distribution represented by Arizona and Texas, uncertainty continues with regard to how this pattern is represented in the southern portion of the range. This latter area represents the boundary between the petitioners' two proposed subspecies (

cactorum

and

ridgwayi

within the proposed reclassification of the species

ridgwayi),

which raises the question of whether there is adequate data to support a change in species classification and define the eastern and western distributions as separate subspecies as proposed by Proudfoot et al. (2006a, entire; 2006b, entire). The Arizona Game and Fish Department (AGFD) completed additional pygmy-owl genetic sampling in the southern portion of the pygmy-owl's range in Mexico in 2022 (Cobbold et al. 2022b, entire). This work did not collect samples far enough south into southern Mexico and Central America to resolve the proposed taxonomic change of Proudfoot et al. (2006a, entire; 2006b, entire), but it did confirm that genetic differentiation does occur across the range of what is currently classified as the subspecies

cactorum,

and that this pattern of differentiation is the result of isolation by distance (Cobbold et al. 2022b, entire). Additionally, this updated analysis and additional genetic sampling did seem to answer the question of whether the Transvolcanic Belt of Mexico at the southern end of the pygmy-owl's range presents a barrier to gene flow across this area.

Based on additional sampling conducted specifically in the area of the Transvolcanic Belt, an area hypothesized to be a potential barrier to movement and gene flow, pygmy-owl samples collected north and south of, as well as within, the Transvolcanic Belt clustered in a single genetically related group (Cobbold et al. (2022b, p. 16). This finding suggests a high degree of gene flow between these population groups. Consequently, the results suggest that the Mexican Transvolcanic Belt does not represent a dispersal barrier to pygmy-owl population groups located on either side of the geological feature within the sampled areas. Additionally, genetic differentiation followed a pattern of isolation by distance, a model under which the strongest differences in genetic structure are expected to occur at the extremities of a species' or subspecies' range (Cobbold et al. 2022b, p. 15). Between the extremities, there is gradual genetic differentiation, rather than abrupt changes, across the range. Sudden changes would be more likely to represent dispersal barriers and, therefore, boundaries between different genetic groupings. Although these datasets show that there are genetic differences across the range of the pygmy-owl, they do not provide adequate evidence of genetic differentiation along the gradient from Arizona to Texas that would warrant the taxonomic changes recommended by Proudfoot et al. (2006a, entire, and 2006b, entire). In particular, sample sizes in the southern portion of the range remain low. Samples in this portion of the range are critical to determining if there are indeed two distinct subspecies of pygmy-owl. While future work and studies may clarify and resolve these issues, we will continue to use the currently accepted distribution of

G. brasilianum cactorum

as described in the 1957 American Ornithologists' Union (now the American Ornithological Society) checklist and various other publications (Friedmann et al. 1950, p. 145; Oberholser 1974, p. 452; Johnsgard 1988, p. 159; Millsap and Johnson 1988, p. 137).

Regulatory and Analytical Framework

Regulatory Framework

Section 4 of the Act (16 U.S.C. 1533) and the implementing regulations in title 50 of the Code of Federal Regulations set forth the procedures for determining whether a species is an endangered species or a threatened species, issuing protective regulations for threatened species, and designating critical habitat for endangered and threatened species. In 2019, jointly with the National Marine Fisheries Service, the Service issued a final rule that revised the regulations in 50 CFR part 424 regarding how we add, remove, and reclassify endangered and threatened species and the criteria for designating listed species' critical habitat (84 FR 45020; August 27, 2019). On the same day, the Service also issued final regulations that, for species listed as threatened species after September 26, 2019, eliminated the Service's general protective regulations automatically applying to threatened species the prohibitions that section 9 of the Act

applies to endangered species (84 FR 44753; August 27, 2019).

The regulations that are in effect and therefore applicable to this final rule are 50 CFR part 424, as amended by (a) revisions that we issued jointly with the National Marine Fisheries Service in 2019 regarding both the listing, delisting, and reclassification of endangered and threatened species and the criteria for designating listed species' critical habitat (84 FR 45020; August 27, 2019); and (b) revisions that we issued in 2019 eliminating for species listed as threatened species are September 26, 2019, the Service's general protective regulations that had automatically applied to threatened species the prohibitions that section 9 of the Act applies to endangered species (84 FR 44753; August 27, 2019).

The Act defines an “endangered species” as a species that is in danger of extinction throughout all or a significant portion of its range, and a “threatened species” as a species that is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range. The Act requires that we determine whether any species is an endangered species or a threatened species because of any of the following factors:

(A) The present or threatened destruction, modification, or curtailment of its habitat or range;

(B) Overutilization for commercial, recreational, scientific, or educational purposes;

(C) Disease or predation;

(D) The inadequacy of existing regulatory mechanisms; or

(E) Other natural or manmade factors affecting its continued existence.

These factors represent broad categories of natural or human-caused actions or conditions that could have an effect on a species' continued existence. In evaluating these actions and conditions, we look for those that may have a negative effect on individuals of the species, as well as other actions or conditions that may ameliorate any negative effects or may have positive effects.

We use the term “threat” to refer in general to actions or conditions that are known to or are reasonably likely to negatively affect individuals of a species. The term “threat” includes actions or conditions that have a direct impact on individuals (direct impacts), as well as those that affect individuals through alteration of their habitat or required resources (stressors). The term “threat” may encompass—either together or separately—the source of the action or condition or the action or condition itself.

However, the mere identification of any threat(s) does not necessarily mean that the species meets the statutory definition of an “endangered species” or a “threatened species.” In determining whether a species meets either definition, we must evaluate all identified threats by considering the species' expected response and the effects of the threats—in light of those actions and conditions that will ameliorate the threats—on an individual, population, and species level. We evaluate each threat and its expected effects on the species, then analyze the cumulative effect of all of the threats on the species as a whole. We also consider the cumulative effect of the threats in light of those actions and conditions that will have positive effects on the species, such as any existing regulatory mechanisms or conservation efforts. The Secretary determines whether the species meets the definition of an “endangered species” or a “threatened species” only after conducting this cumulative analysis and describing the expected effect on the species now and in the foreseeable future.

The Act does not define the term “foreseeable future,” which appears in the statutory definition of “threatened species.” Our implementing regulations at 50 CFR 424.11(d) set forth a framework for evaluating the foreseeable future on a case-by-case basis. The term “foreseeable future” extends only so far into the future as we can reasonably determine that both the future threats and the species' responses to those threats are likely. In other words, the foreseeable future is the period of time in which we can make reliable predictions. “Reliable” does not mean “certain”; it means sufficient to provide a reasonable degree of confidence in the prediction. Thus, a prediction is reliable if it is reasonable to depend on it when making decisions.

It is not always possible or necessary to define foreseeable future as a particular number of years. Analysis of the foreseeable future uses the best scientific and commercial data available and should consider the timeframes applicable to the relevant threats and to the species' likely responses to those threats in view of its life-history characteristics. Data that are typically relevant to assessing the species' biological response include species-specific factors such as lifespan, reproductive rates or productivity, certain behaviors, and other demographic factors.

Analytical Framework

The SSA report documents the results of our comprehensive biological review of the best scientific and commercial data regarding the status of the subspecies, including an assessment of the potential threats to the subspecies. The SSA report does not represent our decision on whether the subspecies should be listed as an endangered or threatened species under the Act. However, it does provide the scientific basis that informs our regulatory decisions, which involve the further application of standards within the Act and its implementing regulations and policies.

To assess cactus ferruginous pygmy-owl viability, we used the three conservation biology principles of resiliency, redundancy, and representation (Shaffer and Stein 2000, pp. 306-310). Briefly, resiliency is the ability of the subspecies to withstand environmental and demographic stochasticity (for example, wet or dry, warm or cold years), redundancy is the ability of the subspecies to withstand catastrophic events (for example, droughts, large pollution events), and representation is the ability of the subspecies to adapt over time to both near-term and long-term changes in its physical and biological environment (for example, climate conditions, pathogens). In general, species viability will increase with increases in resiliency, redundancy, and representation (Smith et al. 2018, p. 306). Using these principles, we identified the subspecies' ecological requirements for survival and reproduction at the individual, population, and subspecies levels, and described the beneficial and risk factors influencing the species' viability.

In the context of the Act, resiliency, redundancy, and representation are influenced by the five listing factors described in the Act. Conversely, the measures of resiliency, redundancy, and representation can indicate the extent to which any or all of the five listing factors are influencing the viability and status of a species in the context of the Act. This relationship between resiliency, redundancy, and representation and the five listing factors is described in more detail in the Threats, Current Condition, Future Scenarios, and Determination of Cactus Ferruginous Pygmy-owl Status sections of this final rule.

The SSA process can be categorized into three sequential stages. During the first stage, we evaluated the individual species' life-history needs. The next stage involved an assessment of the

historical and current condition of the species' demographics and habitat characteristics, including an explanation of how the species arrived at its current condition. The final stage of the SSA involved making predictions about the species' responses to positive and negative environmental and anthropogenic influences. Throughout all of these stages, we used the best available information to characterize viability as the ability of a species to sustain populations in the wild over time. We use this information to inform our regulatory decision.

The following is a summary of the key results and conclusions from the SSA report; the full SSA report can be found at Docket No. FWS-R2-ES-2021-0098 at

https://www.regulations.gov.

Summary of Biological Status and Threats

In this discussion, we review the biological condition of the cactus ferruginous pygmy-owl and its resources, and the threats that influence the subspecies' current and future condition, in order to assess the subspecies' overall viability and the risks to that viability. The overall geographic range of the pygmy-owl is very large (approximately 140,625 square miles [364,217 square kilometers]) and covers two countries, the United States and Mexico. To assist in our analysis, we divided the overall geographic range of the pygmy-owl into five analysis units based upon biological, vegetative, political, climatic, geographical, and conservation differences. The five analysis units are: Arizona, northern Sonora, western Mexico, Texas, and northeastern Mexico. We analyzed each of these analysis units individually and also analyzed the viability of the subspecies in its entire range.

Threats

We reviewed the potential risk factors, and their applicable listing factor, that could be affecting the resiliency, redundancy, and representation of the pygmy-owl now and in the future including: climate change and climate condition (Factor E), habitat loss and fragmentation (Factor A), human activities and disturbance (Factors B and E), waived or ineffective regulatory mechanisms (Factor D), human-caused mortality (Factors B and E), disease and predation (Factor C), and small population size (Factor E). In this final rule, we will discuss only those factors in detail that could meaningfully impact the status of the subspecies. Those risks that are not known to have effects on pygmy-owl populations, such as disease, are not discussed here but are evaluated in the SSA report. The primary risk factors affecting the current and future status of the pygmy-owl are: (1) Habitat loss and fragmentation (Factor A), and (2) climate change and climate conditions (Factor E). We acknowledge, however, that all of the threats discussed in this final rule and the SSA report can exacerbate or contribute to these two primary threats and that it is important to consider all of the known threats to pygmy-owl populations. For a detailed description of the threats analysis, please refer to the SSA report (Service 2022a, chapter 7).

Habitat Loss and Fragmentation

Pygmy-owls require habitat elements, such as mature woodlands, that include appropriate cavities for nest sites, adequate structural diversity and cover, and a diverse prey base. Urbanization, invasive species, and agricultural or forest production are all causing a reduction in the extent of habitat and an increase in habitat fragmentation throughout the geographic range of the subspecies. In response to a comment we received during the public comment period and prior to finalizing this rule, we completed some additional analysis on the effects of certain land uses in Texas and Arizona over the past decade (2010-2020) on pygmy-owl habitat. The commenter provided results of an analysis they did on changes in land cover within the pygmy-owl analysis areas during the time period of 2010-2015 and suggested that the impacts to pygmy-owl habitat were not as great as we presented in the proposed rule and SSA report. Because it is important to consider the scope, scale, and the factors included in different sources of data, we conducted additional analysis using data sources that provided the same type of data that the commenter used in their analysis. This allowed us to compare the results of additional sources of data with the results presented by the commenter. This additional analysis does not change the outcome of our listing decision, but it does provide additional support for our finding that areas of important pygmy-owl habitat have been lost or modified and habitat fragmentation has continued, at least in Texas and Arizona, during this time period. This further analysis can be found in appendix 6 of the SSA report (Service 2022a, appendix 6).

Urbanization

Urbanization causes permanent impacts on the landscape that potentially result in the loss and alteration of pygmy-owl habitat. Residential, commercial, and infrastructure development replace and fragment areas of native vegetation resulting in the loss of available pygmy-owl habitat and habitat connectivity needed to support pygmy-owl dispersal and demographic support (exchange of individuals and rescue effect) of population groups.

Urbanization can also have detrimental effects on wildlife habitat by increasing the channelization or disruption of riverine corridors, the proliferation of exotic species, and the fragmentation of remaining patches of natural vegetation into smaller and smaller pieces that are unable to support viable populations of native plants or animals (Ewing et al. 2005, pp. 1-2; Nabhan and Holdsworth 1998, p. 2). Human-related mortality (

e.g.,

shooting, collisions, and predation by pets) also increases as urbanization increases (Banks 1979, pp. 1-2; Churcher and Lawton 1987, p. 439). Development of roadways and their contribution to habitat loss and fragmentation is a particularly widespread impact of urbanization (Nickens 1991, p. 1). Data from Arizona and Mexico indicate that roadways and other open areas lacking cover affect pygmy-owl dispersal (Abbate et al. 1999, p. 54; Flesch and Steidl 2007, pp. 6-7; Flesch 2017, p. 5; Flesch et al. 2017, entire; Flesch 2021, pp. 12-14). Nest success and juvenile survival were also lower at pygmy-owl nest sites closer to large roadways, suggesting that habitat quality may be reduced in those areas (Flesch and Steidl 2007, pp. 6-7; Flesch 2017, p. 5).

From 2010 to 2020, various land uses, including urbanization, have resulted in the loss of pygmy-owl habitat in Arizona and Texas (Service 2022a, appendix 6), and this loss and fragmentation of pygmy-owl habitat is likely to continue. While there is not a direct correlation between acres of pygmy-owl habitat lost and human population growth, it is reasonable to conclude that, as human population grows, the amount of native habitat lost or fragmented will increase. From 2010 to 2020, population growth rates increased in all Arizona counties where the pygmy-owl has recently occurred: Pima (9.3 percent); Pinal (25.7 percent); and Santa Cruz (13 percent) (OEO 2018, unpaginated). Many cities and towns within the historical distribution of the pygmy-owl in Arizona experienced substantial growth between April 2010 and July 2019: Casa Grande (20.7 percent); City of Eloy (17.8 percent); City of Florence (7.7 percent); Town of Marana (41.9 percent); Town of Oro Valley (12.2 percent); and the Town of

Sahuarita (20.9 percent) (U.S. Census Bureau 2021a, unpaginated). Urban expansion and human population growth trends in Arizona are expected to continue into the future. The Maricopa-Pima-Pinal Counties area of Arizona is expected to grow by as much as 132 percent between 2005 and 2050, creating rural-urban edge effects across thousands of acres of pygmy-owl habitat (AECOM 2011, p. 13). Additionally, a wide area from the international border in Nogales, through Tucson, Phoenix, and north into Yavapai County (called the Sun Corridor “Megapolitan” Area) is projected to have 11,297,000 people by 2050, a 132 percent increase from 2005 (AECOM 2011, p. 13). If build-out occurs as expected, it will encompass a substantial portion of the current and historical distribution of the pygmy-owl in Arizona.

In Texas, the pygmy-owl occurred in relatively high abundance until approximately 90 percent of the mesquite-ebony woodlands of the Rio Grande delta were cleared in 1910-1950 (Oberholser 1974, p. 452). Currently, most of the pygmy-owl habitat occurs on private ranch lands, and, therefore, the threat of habitat loss and fragmentation of the remaining pygmy-owl habitat due to urbanization may be reduced in some areas of Texas. However, urbanization and agriculture along the United States-Mexico border are likely to continue to isolate the Texas population of pygmy-owls by restricting movements between Texas and northeastern Mexico (TDC 2019, entire; Texas Land Trends 2019, entire; USGS 2022, unpaginated).

The United States-Mexico border region has a distinct demographic pattern of permanent and temporary development related to warehouses, exports, and other border-related activities, and patterns of population growth in this area of northern Mexico has accelerated relative to other Mexican States (Pineiro 2001, pp. 1-2). The Sonoran border population has been increasing faster than that State's average and faster than Arizona's border population; between 1990 and 2000, the population in the Sonoran border municipios increased by 33.4 percent, compared to Sonora's average (21.6 percent) and the average increase of Arizona's border counties (27.8 percent). Growth of urban areas in Texas is expected to result in a decrease of rural land uses, further fragmenting habitats in this region (Texas Land Trends 2019, entire). Urbanization has increased habitat conversion and fragmentation, which, along with immigration, population growth, and resource consumption, were ranked as the highest threats to the Sonoran Desert Ecoregion (Nabhan and Holdsworth 1998, p. 1). This pattern focuses development, and potential barriers or impediments to pygmy-owl movements, in a region that is important for demographic support (immigration events and gene flow) of pygmy-owl population groups, including movements such as dispersal.

Significant human population expansion and urbanization in the Sierra Madre foothill corridor may represent a long-term risk to pygmy-owls in northeastern Mexico. From 2010 to 2015 the population in Tamaulipas increased by 8 percent to 3,527,735, and the population in Nuevo León increased by 24 percent to 5,784,442 (DataMexico 2021, unpaginated). Such increasing urbanization results in the permanent removal of pygmy-owl habitat reducing habitat availability and, more significantly, increases habitat fragmentation affecting the opportunity for pygmy-owl movements within northeastern Mexico and between Mexico and Texas. Habitat removal in northeastern Mexico is widespread and nearly complete in northern Tamaulipas (Hunter 1988, p. 8). Demographic support (rescue effect) of pygmy-owl population groups is threatened by ongoing loss and fragmentation of habitat in this area. Urbanization has the potential to permanently alter the last major landscape linkage between the pygmy-owl population in Texas and those in northeastern Mexico (Tewes 1993, pp. 28-29).

Human population growth in Sinaloa, Nayarit, Colima, and Jalisco, Mexico, is ongoing. From 2010 to 2015, the population in Sinaloa grew at a rate of 9.3 percent, Nayarit grew at a rate of 13.9 percent, Jalisco grew at a rate of 13.6 percent, and Colima grew at a rate of 12.4 percent (DataMexico 2021, unpaginated). Growth rates in these areas will likely have some concurrent spread of urbanization despite the fact that most of the growth is taking place in the large cities rather than in the rural areas (Brinkhoff 2016, unpaginated). Additionally, these Mexican States have other threats to pygmy-owl habitat occurring, such as agricultural development and deforestation, that, in combination with habitat lost to urbanization, represent threats to the continued viability of the pygmy-owl in this area (Blackie et al. 2014, p. 1; Burquez 2022, pers. comm.; Mesa-Sierra et al. 2022, entire).

Invasive Species

The invasion of nonnative vegetation, particularly nonnative grasses, has altered the natural fire regime over the Sonoran Desert ecoregion of the pygmy-owl range, in particular, but invasive species impact native habitats in other pygmy-owl analysis units as well (Esque and Schwalbe 2002, p. 165; Lyons et al. 2013, p. 71; Wied et al. 2020, entire). In areas composed entirely of native species, ground vegetation density is mediated by barren spaces that do not allow fire to carry across the landscape. However, in areas where nonnative species have become established, the fine fuel load is continuous, and fire is capable of spreading quickly and efficiently (Esque and Schwalbe 2002, p. 175; Wied et al. 2020, p. 48). As a result, fire has become a significant threat to the native vegetation of the Sonoran Desert. Sonoran Desert vegetation is not fire adapted, and many such vegetative communities in Arizona are no longer in a natural or historical state. Instead, these vegetative communities and their fire dynamics have been inalterably changed by nonnative grasses and forbs, and in some areas by woody shrubs and trees (Gornish and Howery 2019, entire). Nonnative plant communities are problematic not only for imperiled species such as the pygmy-owl, but also for land managers whose goals include forest stewardship and wildfire mitigation for public safety and natural resource protection. The Arizona Wildfire Risk Assessment Portal estimates that a substantial portion of the pygmy-owl range in Arizona (2,433,763 ha; 6,013,959 acres) has a moderate to high risk of experiencing adverse effects of wildfire in the foreseeable future. As discussed elsewhere in this final rule and in our SSA report, such adverse effects include the destruction of roosting and nesting substrate provided by mature trees and columnar cacti. Using conservative estimates from post-fire monitoring performed by the Tonto National Forest, the Arizona Department of Forestry and Fire Management (ADFFM) concluded that over 30 million saguaros could be lost and unlikely to regenerate if a large portion of the area under risk were to burn (ADFFM 2022, pers. comm.).

Nonnative annual plants prevalent within the Sonoran range of the pygmy-owl include

Bromus rubens

and

B. tectorum

(brome grasses),

Schismus

spp. (Mediterranean grasses), and Sahara mustard (

Brassica tournefortii

) (Esque and Schwalbe 2002, p. 165; ASDM 2021, unpaginated). However, the nonnative species that is currently one of the greatest threats to vegetation communities in Arizona and Texas in the United States and northeastern and northwestern Mexico is the perennial

Cenchrus ciliaris

(buffelgrass), which is

prevalent and increasing throughout much of the range of the pygmy-owl (Burquez and Quintana 1994, p. 23; Van Devender and Dimmit 2006, p. 5; Lyons et al. 2013, pp. 68-69; Wied et al. 2020, pp. 47-48).

Buffelgrass is not only fire-tolerant (unlike native Sonoran Desert plant species) but is actually fire-promoting (Halverson and Guertin 2003, p. 13; Lyons et al. 2013, p. 71). Invasion sets in motion a grass-fire cycle where nonnative grass provides the fuel necessary to initiate and promote fire. Nonnative grasses recover more quickly than native grass, tree, and cacti species and cause a further susceptibility to fire (D'Antonio and Vitousek 1992, p. 73; Schmid and Rogers 1988, p. 442). While a single fire in an area may or may not produce long-term reductions in plant cover or biomass, repeated wildfires in a given area, due to the establishment of nonnative grasses, are capable of ecosystem type-conversion from native desertscrub to nonnative annual grassland (Wied et al. 2020, p. 48). These repeated fires may render the area unsuitable for pygmy-owls and other native wildlife due to the loss of trees and columnar cacti and reduced diversity of cover and prey species (Brooks and Esque 2002, p. 336; Wied et al. 2020, p. 48).

The distribution of buffelgrass has been supported and promoted by governments on both sides of the United States-Mexico border as a resource to increase range productivity and forage production (Lyons et al. 2013, p. 65). A 2006 publication estimates that 143,504 ha (3.5 million ac) have been converted to buffelgrass in Sonora, and that between 1990 and 2000, there was an 82 percent increase in buffelgrass coverage (Franklin et al. 2006, pp. 62, 66, 67). Following establishment, buffelgrass fuels fires that destroy Sonoran desertscrub, thornscrub, and, to a lesser extent, tropical dry forest; the disturbed areas are quickly converted to open savannas composed entirely of buffelgrass, which removes pygmy-owl nest substrates and generally renders areas unsuitable for future occupancy by pygmy-owls. Buffelgrass is now fully naturalized in most of Sonora, southern Arizona, and some areas in central and southern Baja California (Burquez-Montijo et al. 2002, p. 131) and now commonly spreads without human cultivation (Burquez et al. 1998, p. 26; Perramond 2000, p. 131; Arriaga et al. 2004, pp. 1509-1511).

Because of the significance of the issue of buffelgrass invasion in Arizona, the Governor of Arizona formed the Arizona Invasive Species Advisory Council in 2005, and the Southern Arizona Buffelgrass Working Group developed the Southern Arizona Buffelgrass Strategic Plan in 2008 (Buffelgrass Working Group 2008, entire) in order to coordinate the control of buffelgrass. Because of its negative impacts to native ecosystems, buffelgrass was declared a noxious weed by the State of Arizona in March 2005. This buffelgrass working group is now led by the Arizona-Sonora Desert Museum (ASDM). The ASDM is currently mapping the extent, and control, of buffelgrass in southern Arizona in an effort to inform and direct management activities (ASDM 2022, unpaginated). These efforts are helping to manage buffelgrass invasion in southern Arizona.

Similar issues occur in Texas. Buffelgrass is now one of the most abundant nonnative grasses in South Texas, and a prevalent invasive grass within the range of the pygmy-owl. During the 1950s, Federal and State land management agencies promoted buffelgrass as a forage grass in South Texas (Smith 2010, p. 113; Lyons et al. 2013, p. 69). Buffelgrass is very well adapted to the hot, semi-arid climate of South Texas due to its drought resistance and ability to aggressively establish in heavily grazed landscapes (Smith 2010, p. 113; Wied et al. 2020, p. 48). Despite increasing awareness of the ecological damage caused by nonnative grasses, buffelgrass is still planted in areas affected by drought and overgrazing to stabilize soils and to increase rangeland productivity. Prescribed burning used for brush control typically promotes buffelgrass forage production in South Texas (Hamilton and Scifres 1982, p. 11). Buffelgrass often creates homogeneous monocultures by out-competing native plants for essential resources (Lyons et al. 2013, p. 8). Furthermore, buffelgrass produces phytotoxins in the soil that inhibit the growth of neighboring native plants (Vo 2013, unpaginated). With regard to pygmy-owl habitat, the loss of trees and canopy cover and the creation of dense ground cover resulting from buffelgrass conversion reduces nest cavity availability, cover for predator avoidance and thermoregulation, and prey availability. Overall, buffelgrass is the dominant herbaceous cover on 10 million ha (24,710,538 acres) in southern Texas and northeastern Mexico (Wied et al. 2020, p. 47).

The impacts of buffelgrass establishment and invasion are substantial for the pygmy-owl in the United States and Mexico because conversion results in the loss of important habitat features, particularly columnar cacti and trees that provide nest sites. Buffelgrass also reduces habitat diversity by creating monocultures of buffelgrass and out-competing native vegetation species (Lyons et al. 2013, pp. 66-67; Wied et al. 2020, p. 48), which decreases prey availability for the pygmy-owl by decreasing the habitat compositional and structural diversity. Buffelgrass invasion and the subsequent fires eliminate most columnar cacti, trees, and shrubs of the desert (Burquez-Montijo et al. 2002, p. 138). This elimination of trees, shrubs, and columnar cacti from these areas is a potential threat to the survival of the pygmy-owl in the northern part of its range, as these vegetation components are necessary for roosting, nesting, protection from predators, and thermal regulation. Invasion and conversion to buffelgrass also negatively affect the diversity and availability of prey species in these areas (Franklin et al. 2006, p. 69; Avila-Jimenez 2004, p. 18; Burquez-Montijo et al. 2002, pp. 130, 135).

Buffelgrass is adapted to dry, arid conditions and does not grow in areas with high rates of precipitation or high humidity, above elevations of 1,265 m (4,150 ft), or in areas with freezing temperatures. Areas that support pygmy-owls south of Sonora and northern Sinaloa typically are wetter and more humid, and conditions are not as favorable for the invasion of buffelgrass. Surveys completed in Sonora and Sinaloa in 2006 noted buffelgrass was present in Sonora and northern Sinaloa, but the more southerly locations were noted as sparse or moderate (Van Devender and Dimmitt 2006, p. 7). However, because buffelgrass was first introduced to Mexico in Tamaulipas and Neuvo Leon, and then subsequently to Sonora and Sinaloa (Lyons et al. 2013, pp. 68-69), buffelgrass and its associated impacts are found in all five of the pygmy-owl analysis units used in our analysis for this final rule.

Agricultural Production and Wood Harvesting

Agricultural development and wood harvesting can result in substantial impacts to the availability and connectivity of pygmy-owl habitat. Conversion of native vegetation communities to agricultural fields or pastures for grazing has occurred within historical pygmy-owl habitat in both the United States and Mexico, and not only removes existing pygmy-owl habitat elements, but also can affect the long-term ability of these areas to return to native vegetation communities once agricultural activities cease. Wood harvesting has a direct effect on the

amount of available cover and nest sites for pygmy-owls and is often associated with agricultural development. Wood harvesting also occurs to supply firewood and charcoal, and to provide material for cultural and decorative wood carvings.

In Arizona, although new agricultural development is limited, the effects to historical habitat are still evident. Many areas that historically supported meso- and xeri-riparian habitat have been converted to agricultural lands, and associated groundwater pumping has affected the hydrology of these valleys (Jackson and Comus 1999, pp. 233, 249). These riparian areas are important pygmy-owl habitat, especially within drier upland vegetation communities like Sonoran desertscrub and semi-desert grasslands.

Habitat fragmentation as a result of agricultural development has also occurred within Texas. Brush-clearing, pesticide use, and irrigation practices associated with agriculture have had detrimental effects on the Lower Rio Grande Valley (Jahrsdoerfer and Leslie 1988, p. 1). From the 1920s until the early 1970s, over 90 percent of pygmy-owl habitat in the Lower Rio Grande Valley of Texas was cleared for agricultural and urban expansion (Oberholser 1974, p. 452). The Norias Division of the King Ranch in southern Texas has been at the center of most research on pygmy-owls in Texas (Mays 1996, entire; Proudfoot 1996, entire), but has been isolated by agricultural expansion, which has restricted pygmy-owl dispersal (Oberholser 1974). This expansion has resulted in loss of pygmy-owl habitat connectivity between pygmy-owl population groups in Texas and in Mexico. From 2010 to 2020, various land uses, including agricultural development and wood harvesting, have resulted in some loss of pygmy-owl habitat in Arizona and Texas (Service 2022a, Appendix 6), and this loss and fragmentation of pygmy-owl habitat is likely to continue based on population growth projections (HHS 2017, unpaginated; OEO 2018, unpaginated; TDC 2019, entire; Pinal County 2019, p. 126; Gonzales 2020, unpaginated).

Historically, agriculture in Sonora, Mexico, was restricted to small areas with shallow water tables, but it had, nonetheless, seriously affected riparian areas by the end of the nineteenth century. For example, in the Rio Mayo and Rio Yaqui coastal plains, nearly 1 million ha (2.5 million ac) of mesquite, cottonwood, and willow riparian forests and coastal thornscrub disappeared after dams upriver started to operate (Burquez and Martinez-Yrizar 2007, p. 543). Other Mexican States within the range of the pygmy-owl show similar potential for habitat loss. For example, in Tamaulipas, areas under irrigation increased from 174,400 to 494,472 ha (431,000 to 1.22 million ac) between 1998 and 2004, with an area of 668,872 ha (1.65 million ac) equipped for irrigation. However, agricultural development in the States of Colima, Jalisco, Nayarit, and Nuevo Leon had decreases in the amount of irrigated lands over the same period (FAO 2007, unpaginated).

There is some evidence that historical agricultural practices by indigenous peoples and early settlers provided and potentially enhanced available pygmy-owl habitat in Arizona, primarily through the development of irrigation canals that promoted the presence of woody vegetation (BOR 1947, unpaginated; Johnson et al. 2004, p. 139). However, more recent agricultural developments typically remove areas of native vegetation resulting in pygmy-owl habitat loss and fragmentation over relatively large areas, causing reductions in ground and surface waters impacting riparian systems important to the pygmy-owl and pygmy-owl prey species, and resulting in habitat fragmentation and loss of habitat connectivity for the pygmy-owl. While the loss and fragmentation of habitat is more of an historical impact in Arizona and Texas, some agricultural development continues in these areas and some historical impacts are still evident. In Mexico, agricultural development is an ongoing threat to pygmy-owl habitat (Burquez 2022, pers. comm.).

Wood harvesting is also a potential threat to pygmy-owl habitat. Ironwood (

Olneya tesota

) and mesquite (

Prosopis

spp.) are harvested throughout the Sonoran Desert for use as charcoal, fuelwood, and carving (Burquez and Martinez Yrizar 2007, p. 545). For instance, by 1994, 202,000 ha (500,000 ac) of mesquite had been cleared in northern Mexico to meet the growing demand for mesquite charcoal (Haller 1994, p. 1). Flesch (2021, pp. 11, 13) noted that pygmy-owl habitat impacts from charcoal operations are still occurring in Sonora. Unfortunately, woodcutters and charcoal makers used large, mature mesquite and ironwood trees growing in riparian areas (Taylor 2006, p. 12), which is the tree class that is of most value as pygmy-owl habitat. Loss of leguminous trees results in long-term effects to the soil as these trees add organic matter, fix nitrogen, and add sulfur and soluble salts, affecting overall habitat quality and quantity (Rodriguez-Franco and Aguirre 1996, p. 6-47). Ironwood and mesquite trees are important nurse plant species for saguaros, the primary nesting substrate for pygmy-owls in the northern portion of their range (Burquez and Quintana 1994, p. 11). Declining tree populations in the Sonoran Desert as a result of commercial uses and land conversion threatens other plant species and may alter the structure and composition of the vertebrate and invertebrate communities as well (Bestelmeyer and Schooley 1999, p. 644). This has implications for pygmy-owl prey availability because pygmy-owls rely on a seasonal diversity of vertebrate and invertebrate prey species; loss of tree structure and diversity reduces prey diversity and availability.

Once common in areas of the Rio Grande delta, significant habitat loss and fragmentation due to woodcutting have now caused the pygmy-owl to be a rare occurrence in this area of Texas. Oberholser (1974, p. 452) concluded that agricultural expansion and subsequent loss of native woodland and thornscrub habitat, begun in the 1920s, preceded the rapid demise of pygmy-owl populations in the Lower Rio Grande Valley of southern Texas. Because much of the suitable pygmy-owl habitat in Texas occurs on private ranches, habitat areas are subject to potential impacts that are associated with ongoing ranch activities such as grazing, herd management, fencing, pasture improvements, construction of cattle pens and waters, road construction, and development of hunting facilities. Brush-clearing, in particular, has been identified as a potential factor in present and future declines in the pygmy-owl population in Texas (Oberholser 1974, p. 452). Conversely, ranch practices that enhance or increase pygmy-owl habitat to support ecotourism can contribute to conservation of the pygmy-owl in Texas (Wauer et al. 1993, p. 1076).

Habitat fragmentation in northeastern Mexico is extensive, with only about two percent of the ecoregion remaining intact, and no habitat blocks larger than 250 square km (96.5 square mi), and no significant protected areas (Cook et al. 2001, p. 4). Fire is often used to clear woodlands for agriculture in this area of Mexico, and many of these fires are not adequately controlled. There may be fire-extensive related effects to native plant communities (Cook et al. 2001, p. 4); however, there is no specific information available for how much area may be affected by this activity.

Areas of dry subtropical forests, important habitat for pygmy-owls in southwestern Mexico, have been used by humans through time for settlement

and various other activities (Trejo and Dirzo 2000, p. 133; Blackie et al. 2014, pp. 1-2). The long-term impact of this settlement has converted these dry subtropical forests into shrublands and savannas lacking large trees, columnar cacti, and cover and prey diversity that are important pygmy-owl habitat elements. In Mexico, tropical dry forest is the major type of tropical vegetation in the country, covering over 60 percent of the total area of tropical vegetation. About 8 percent (approximately 160,000 square km (61,776 square mi)) of this forest remained intact by the late 1970s, and an assessment made at the beginning of the present decade suggested that 30 percent of these tropical forests have been altered and converted to agricultural lands and cattle grasslands (Trejo and Drizo 2000, p. 134; Mesa-Sierra et al. 2022, unpaginated). Tropical dry forests, such as Selva baja caducifolia and Bosque tropical caducifolio, are the most important reservoir of biodiversity along the Pacific coast of Mexico (Burquez 2022, pers. comm.). Extensive reductions in these habitats have occurred in the past. For instance, extensive irrigation systems have been developed along the coasts of Sinaloa and Nayarit, and in more localized areas in Jalisco, Michoacán, and Guerrero. These and other land-transformation pressures affecting tropical dry forests have not diminished with time (Burquez 2022, pers. comm.).

Summary of Habitat Loss and Fragmentation

In summary, pygmy-owls require habitat elements such as mature woodlands that include appropriate cavities for nest sites, adequate structural diversity and cover, and a diverse prey base. These habitat elements need to be available across the geographic range of the pygmy-owl and spatially arranged to allow connectivity between habitat patches. Pygmy-owl habitat loss and fragmentation have affected, and are continuing to affect, pygmy-owl viability throughout its range.

These threats vary in scope and intensity throughout the pygmy-owl's geographic range, and specific threats are a more significant issue in certain parts of the range than in others. For example, in Arizona and Northern Sonora, pygmy-owl habitat loss and fragmentation resulting from urbanization, changing fire regimes due to the invasion of buffelgrass, and agricultural development and woodcutting are significant threats that have negatively affected pygmy-owl habitat. In Texas, historical loss of habitat has reduced the pygmy-owl range, and, in Texas and other areas of the pygmy-owl's range, these past impacts continue to affect the current extent of available pygmy-owl habitat, because of the extended time it takes for these lands to recover. Therefore, even if habitat destruction ceases, the negative effects of past land use are expected to continue in many of these areas into the future, and this will be a cumulative impact with current impacts from invasive species, agricultural development, and other land use practices (Texas Land Trends 2019, entire; Wied et al. 2020, entire; DHS 2020, unpaginated; USGS 2022, unpaginated).

One of the most pressing issues for the U.S.-Mexico border is the impact of illegal human and vehicular traffic through these unique and environmentally sensitive areas. Many of these locations now bear the scars of wildcat trails, abandoned refuse, and trampled vegetation (Marris 2006, p. 339; Walker and Pavlakovich-Kochi 2003, p. 15). Trails and roadways remove pygmy-owl habitat features; noise and disturbance from people and vehicles disrupt important behaviors; and there is an increased risk of fire in important habitats resulting from cooking and warming fires, as well as signal fires used by cross-border immigrants and smugglers.

For the remainder of the pygmy-owl's range and habitat in Mexico (northeastern Mexico and south of Sonora), data available for our analysis were limited. Available data that we considered regarding population growth and land use patterns indicates that human population growth throughout Mexico is occurring (INEGI 2021, unpaginated; CONAPO 2014, p. 25; DataMexico 2021, unpaginated). Historical loss of pygmy-owl habitat in northeastern Mexico has occurred, and recent increases in agricultural development are occurring in Tamaulipas (FAO 2007, unpaginated). Tropical dry forests, one of the most biologically significant vegetation communities in Mexico and important pygmy-owl habitat, has been significantly reduced and is continuing to be lost (Burquez 2022 pers. comm.; Mesa-Sierra et al. 2022, unpaginated).

This information indicates that the impacts to pygmy-owl habitat discussed herein may be having different levels of effects on the populations of pygmy-owls throughout their range and, while not every activity is occurring in every analysis unit, every analysis unit is experiencing habitat loss and fragmentation (Service 2022a, appendix 5). Enríquez and Vazquez-Perez (2017, p. 546) indicate that, during the last 50 years, Mexico has seen drastic changes in land uses due to rapid urbanization and industrialization, which has been poorly planned. The result has been impacts to the natural environment, including the degradation and loss of biological diversity in Mexico. There has been limited work in Mexico, however, to understand what the direct impacts of these threats are on owl population losses and changes in distribution and abundance of subspecies in the long term (Enríquez and Vazquez-Perez 2017, p. 546).

Habitat loss and fragmentation will impact both the eastern and western populations of pygmy-owls through reduced size and number of suitable blocks of nesting habitat and nest cavity availability, loss and reduction of habitat connectivity and the ability of pygmy-owls to move across the landscape to provide demographic and genetic rescue, loss and reduction of prey availability, and the increase of potential threats related to predation, pesticides, and human disturbance.

Climate Change and Climate Conditions

Enough time has passed since the early predictions of impacts of climate change that we have seen evidence of those predicted impacts on vegetation communities across the range of the pygmy-owl (Vermote et al. 2014, unpaginated; Romero-Lankao, et al. 2014, p. 1459; Williams et al. 2020, p. 317; IPCC 2022, entire). New climate models and projections, updated Normalized Difference Vegetation Index (NDVI) datasets, and an assessment examining pygmy-owl's vulnerability to climate change have been completed since our analysis in the 2011 pygmy-owl 12-month finding (Bagne and Finch 2012, pp. 67-73; Coe et al. 2012, entire; Jiang and Yang 2012, entire; IPCC 2014b, entire; Romero-Lankao, et al. 2014, entire; Melillo et al. 2014, entire; Vermote et al. 2014, unpaginated; AdaptWest Project 2015, unpaginated; Cook et al. 2015, entire; Pascale et al. 2017, p. 806; USGCRP 2018, chapters 23 and 25; Gonzalez et al. 2018, entire; Christensen et al. 2018, p. 5409; BOR 2021, entire; AdaptWest Project 2022, unpaginated; IPCC 2022, entire). These projections continue to predict impacts at the same or increasing levels upon the landscape in areas where the pygmy-owl occurs.

In the SSA report, the proposed rule, and this final listing rule, we used newer modeling related to climate that was not used in our 2011 12-month finding, and this change reduced the subjectivity of our approach to evaluate the effects to pygmy-owl habitat effects

(Vermote et al. 2014, unpaginated; AdaptWest Project 2015, unpaginated; Wang et al. 2016, pp. 6-7; Dewes et al. 2017, p. 17; Diffenbaugh et al. 2017, entire; AdaptWest Project 2022, unpaginated; Service 2022a, chapter 6, appendices 2 and 3). Furthermore, additional IPCC reports have been published since 2011, as well as National Climate Assessments, and we have included the appropriate information found in these sources in our climate analysis to ensure that we considered the most current and best information available. These sources represent the current understanding of the evidence and effects of climate change (IPCC 2014b, entire; Melillo et al. 2014, entire; USGCRP 2018, chapters 23 and 25; IPCC 2022, entire).

Climate change projections within the geographic range of the pygmy-owl show that increasing temperatures, decreasing precipitation, and increasing intensity of weather events are likely (Karmalkar et al. 2011, entire; Bagne and Finch 2012, entire; Coe et al. 2012, entire; and Jiang and Yang 2012, entire; BOR 2021; p. 23). Climate influences pygmy-owl habitat conditions and availability through the loss of vegetation cover, reduced prey availability, increased predation, reduced nest site availability, and vegetation community change. The majority of the current range of the pygmy-owl occurs in tropical or subtropical vegetation communities, which may be reduced in coverage if climate change results in hotter, more arid conditions. Extended drought has and continues to affect vegetation communities used by the pygmy-owl in the United States (NDMC 2022, unpaginated). Additionally, models predict that the distribution of suitable habitat for saguaros, the primary pygmy-owl nesting substrate within the Sonoran Desert ecoregion, will substantially decrease over the next 50 years under a moderate climate change scenario (Weiss and Overpeck 2005, p. 2074; Thomas et al. 2012, p. 43).

Climate change scenarios project that drought will occur more frequently and increase in severity, with a decrease in the frequency and increase in severity of precipitation events (Seager et al. 2007, p. 9; Cook et al. 2015, p. 6; Pascale et al. 2017, p. 806; Williams et al. 2020, p. 317; BOR 2021, p. 23). Drought and changes to the timing and intensity of precipitation events may reduce available cover and prey for pygmy-owls adjacent to riparian areas through scouring flood events and reduced moisture retention. The extent to which changing climatic patterns will affect the pygmy-owl is better understood following the past decade of observations in the field. For example, in northern Sonora, the summer monsoon's precipitation (or lack thereof) has a significant effect on whether or not juvenile pygmy-owls reach adulthood, as the lizards preferred by these owls are more abundant when summer precipitation does not fall below normal levels. Climate change has made the amount of summer precipitation more variable than it used to be. Average summer monsoons in the Sonoran Desert produce 2.43 inches of rain. In years like 2019 and 2020, however, when summer rainfall was significantly below average (0.66 inches and 1.0 inches respectively), there was less prey for juveniles to eat as they entered adulthood, and thus fewer owls survived. In years like 2015-2016, when the amount of precipitation from the summer monsoon was above average, more juveniles survived to adulthood and owl population levels in those years did not decline (Flesch 2021, entire).

Synergistic interactions are likely to occur between the effects of climate change and habitat fragmentation and loss. Climate change projections indicate that conditions will likely favor increased occurrence and distribution of nonnative, invasive species and alteration of historical fire regimes. Climate change may also affect the viability of the pygmy-owl through precipitation-driven changes in plant and insect biomass, which in turn influence abundance of lizards, small mammals, and birds (Jones 1981, p. 111; Flesch 2008, p. 5; Flesch et al. 2015, p. 26). Decreased precipitation generally reduces plant cover and insect productivity, which in turn reduces the abundance and availability of pygmy-owl prey species. Similarly, increased temperatures reduce pygmy-owl prey activity due to increased energetic demands of thermoregulation and a decreased availability of prey and cover (Flesch 2014, p. 116; Flesch et al. 2015, p. 26). These indirect effects on prey availability and direct effects on prey activity affect nestling growth, development, and survival. When decreased precipitation affects food supply and increased temperature affects prey activity, reduced pygmy-owl productivity is likely to result in reduced pygmy-owl resiliency (Flesch et al. 2015, p. 26).

A recent downscaled hydroclimate study reported predicted climate impacts within the range of the pygmy-owl in Arizona (BOR 2021, entire). In general, the scenarios for the greenhouse gas emissions model that approximates our current trajectory predicts that monsoonal rain will be reduced, as well as more highly variable. Temperatures will also increase significantly during both winter (between 1.88 °Fahrenheit (F) and 3.20 °F) and summer (between 2.59 °F and 3.34 °F). As a result, streamflow throughout the area covered by this effort, including the Avra and Altar valleys, which are occupied by pygmy-owls, is likely to be reduced, which would negatively impact infiltration into the aquifer. These changes are likely to impact pygmy-owls and their prey species in a variety of ways, many of them negative. For example, increased evapotranspiration and reduced soil moisture could negatively impact prey species that pygmy-owls depend on, reduce the amount and/or quality of vegetation necessary for roosting, thermoregulation, and predator avoidance, amplify fire risk and concomitant compromise of necessary woodland vegetation and availability of mature saguaro cacti, as well as lead to reduced nestling fitness if nest cavity temperatures rise too high (Flesch et al. 2015, p. 26; Service 2022a, chapter 6; Flesch 2021, entire). Climate change can also influence natural events, such as hurricanes and tropical storms, which can modify and fragment pygmy-owl habitats, primarily through loss of woody cover, as evidenced in Texas and northeastern Mexico (Hurricane Harvey in 2017, Hurricane Hanna in 2020, and Hurricane Ida in 2021). Historical and ongoing threats to the pygmy-owl from habitat loss and fragmentation as well as from climate change and climate conditions, have shaped the current habitat and population conditions of the subspecies throughout its range.

In summary, climate change and its associated change in conditions on the landscape will impact both the eastern and western pygmy-owl populations through habitat loss and fragmentation, reduced nest cavity availability, reduced prey populations, lower productivity, and reduced survivability.

Current Condition

To assess resiliency, we evaluated six components that broadly related to the subspecies' population demography or physical environment and for which we had data sufficient to conduct the analysis. We assessed each analysis unit's physical environment by examining three components determined to have the most influence on the subspecies: habitat intactness, prey availability, and vegetation health and cover (Flesch 2017, entire). We also assessed each analysis unit's demography through abundance, occupancy, and evidence of reproduction. We established

parameters for each component by evaluating the range of existing data and separating those data into categories based on our understanding of the subspecies' demographics and habitat. Using the demographic and habitat parameters, we then categorized the overall condition of each analysis unit. We provide a summary of each of the six factors below and describe them in detail in the SSA report (Service 2022a, entire).

Demographic Factors

Abundance:

Larger populations have a lower risk of extinction than smaller populations (Pimm et al. 1988, pp. 773-775; Trombulak et al. 2004, p. 1183). Small populations are less resilient and more vulnerable to the effects of demographic, environmental, and genetic stochasticity, and have a higher risk of extinction than larger populations (Trombulak et al. 2004, p. 1183). Small populations may experience increased inbreeding, loss of genetic variation, and ultimately a decreased potential to adapt to environmental change (Trombulak et al. 2004, p. 1183; Harmon and Braude 2010, p. 125; Benson et al. 2016, pp. 1-2). The abundance of pygmy-owls within each analysis unit must be high enough to support persistence of pygmy-owl population groups (multiple breeding pairs of pygmy-owls within relatively discrete geographic areas) within the analysis unit. This persistence of population groups is accomplished by having adequate patches of habitat to support multiple nesting pairs of pygmy-owls and their offspring, having adequate habitat connectivity to support establishment of additional territories by dispersing young, and having a supply of floaters (unpaired individuals of breeding age) within each pygmy-owl population group to offset loss of breeding adults and to provide potential mates for dispersing juveniles. In order to compare the resiliency of the individual analysis units, we estimated the general magnitude of the abundance of pygmy-owls within each analysis unit (Service 2022a, chapter 6 and table 4.2). However, these estimates of the magnitude of abundance should not be construed as actual population estimates (see

Summary of Current Condition of the Subspecies

below).

Occupancy:

Sufficiently resilient pygmy-owl populations must occupy large enough areas such that stochastic events and environmental fluctuations that affect individual pygmy-owls, or population groups of pygmy-owls, do not eliminate the entire population. Pygmy-owls are patchily distributed across the landscape in population groups of nesting owls. Each of these population groups must contain a high enough abundance of pygmy-owls to enable the population group to persist on the landscape over time. Enough occupied population groups of pygmy-owls must also exist on the landscape, with interconnected habitat supporting movement among population groups, so that each population group can receive or exchange individuals with any given adjacent population group.

Pygmy-owl occupancy is an indicator of habitat conditions as well as demographic factors, such as reproduction and survival. Habitats that support a high abundance of pygmy-owls are better able to provide floaters and available mates to dispersing pygmy-owls from adjacent populations. These floaters are able to serve as replacement breeders if either or both members of an existing breeding pair are lost. Observations indicate that if a site is occupied by a breeding pair, they will breed. Survival of adults also affects occupancy, as some occupied sites will be abandoned if one of the adult breeders perishes. These sites can be reoccupied in the future when floaters or dispersing birds move into the area.

Evidence of reproduction:

Adequately resilient pygmy-owl populations must also reproduce and produce a sufficient number of young such that recruitment equals or exceeds mortality. Current population size and abundance reflects previous influences on the population and habitat, while reproduction and recruitment reflect population trends that may be stable, increasing, or decreasing in the future. Adequately resilient populations of the pygmy-owl must have sufficient abundance to replace members of breeding pairs that have been lost and to support persistent population groups of nesting pygmy-owls through dispersal. However, the necessary reproductive rate needed for a self-sustaining population is unknown. Additionally, key demographic parameters of pygmy-owl populations (

e.g.,

survival, life expectancy, lifespan, productivity, etc.) are unknown throughout most of the geographic range. Due to the lack of information on demographic parameters of reproduction, recruitment, and survival, we broadly considered evidence of reproduction to include any evidence of reproduction (

e.g.,

active nests, presence of eggs or nestlings, fledglings, etc.), as well as persistence of occupied territories and population groups in an area over a sufficient amount of time to indicate evidence of reproduction. Thus, evidence of reproduction on a consistent basis over time likely indicates a sufficiently resilient population.

Habitat intactness:

Adequately resilient pygmy-owl populations need intact habitat that is large enough to support year-round occupancy, as well as connectivity between habitat patches to enable dispersal. As the baseline for our analysis of habitat intactness, we modeled suitable vegetation types across the range of the pygmy-owl that provide habitat for the pygmy-owl (Service 2022a, chapter 6 and appendix 1). We know that the modeled suitable vegetation does not equal pygmy-owl habitat and that the acres of suitable vegetation are greater than the actual acres of pygmy-owl habitat. However, modeled suitable vegetation does provide a surrogate for acres of pygmy-owl habitat. Pygmy-owls are patchily distributed across much of their geographic range. These pygmy-owl population groups are dependent on interchange of individuals in order to maintain adequate abundance and genetic diversity on the landscape. Habitat connectivity is crucial to maintaining pathways for the interchange of individuals among pygmy-owl population groups (Flesch 2017, entire).

Prey availability:

Adequate prey availability is a key component for maintaining resiliency in pygmy-owl populations. Year-round prey availability is essential throughout the range of the pygmy-owl, with portions of the geographic range characterized by seasonal variability in available prey resources. The abundance of many of these prey species is influenced by annual and seasonal precipitation through increases and decreases in vegetation cover and diversity, which also influences insect abundance and availability. Sufficiently resilient pygmy-owl populations require adequate precipitation to support year-round prey availability. This includes appropriately timed precipitation to support seasonally available prey such as lizards, insects, and small mammals.

Vegetation cover:

Sufficiently resilient pygmy-owl populations require adequate vegetation to provide cover for predator avoidance, thermoregulation, hunting, and nest cavities. Of primary importance for cover is the presence of woody vegetation canopy. Maintenance of the health and vigor of this woody cover is a key component to maintaining resiliency of pygmy-owl populations.

Summary of Current Condition of the Subspecies

Currently, the cactus ferruginous pygmy-owl occurs from southern Arizona, south to Michoacán in the

western portion of its range, and from southern Texas to Tamaulipas and Nuevo Leon in the eastern portion of its range. For our analysis, we divided the pygmy-owl's overall range into five analysis units: Arizona, northern Sonora, western Mexico, Texas, and northeastern Mexico (see Figure 1). In order to compare the resiliency of the individual analysis units, we estimated the general magnitude of the abundance of pygmy-owls within each analysis unit (Service 2022a, chapter 6 and table 4.2). This estimated magnitude of abundance is one of the demographic factors used to evaluate the resiliency of each analysis unit. These estimates of the magnitude of abundance should not be construed as actual population estimates. We lack sufficient data to make any statistically meaningful population estimates for any of the analysis units. Rather, these estimates of the magnitude of pygmy-owl abundance are used as a tool to compare the general abundance of pygmy-owls in each analysis unit.

The primary factors currently affecting the condition of cactus ferruginous pygmy-owl populations include changing climate conditions, and habitat fragmentation and loss. The threats contributing to or resulting from these two primary factors do not occur consistently across all analysis units, but all analysis units are being impacted by one or more of the threats discussed in this final rule and the SSA report (see Service 2022a, appendix 5 for a more detailed discussion of the particular threats impacting each analysis unit). Information from the northern Sonora analysis unit provides evidence of what factors contribute to the viability of pygmy-owl populations. Flesch (2014, pp. 114-117) showed that, at least in the northern portion of the western pygmy-owl population, pygmy-owl abundance was consistently higher and varied less in areas with more nest cavities, more riparian vegetation, and lower land-use intensity, suggesting these factors are important drivers of pygmy-owl habitat quality. We have also identified which of the five listing factors identified in the Act are influencing the current condition of the pygmy-owl.

Resiliency

The Arizona analysis unit currently has the lowest pygmy-owl abundance of all analysis units, which is estimated to be in the low hundreds. Habitat fragmentation and loss from urbanization and increases in invasive species such as buffelgrass, have reduced the availability and connectivity of habitat in this analysis unit (Factor A). Additionally, climate conditions have reduced prey availability and vegetative cover through increased temperatures and drought (Factor E). These factors result in a reduced capacity for this analysis unit to withstand stochastic events and result in a low resiliency currently.

The northern Sonora analysis unit has an estimated pygmy-owl abundance in the high hundreds. However, this analysis unit is affected by habitat fragmentation from urbanization, agricultural development, and associated infrastructure (Flesch 2021, pp. 12-14) (Factor A). These stressors increase water use and, in conjunction with climate conditions, result in a reduction in the quality and availability of pygmy-owl habitat (Factor A). Abundance of pygmy-owls in the Sonoran Desert in northwest Mexico, for example, declined about 19-27 percent over a 12-year period, and change in owl abundance was highly associated with variation in precipitation and temperature (Factor E). In addition, hot, dry conditions influence the behavior and health of prey species the owl relies upon for food. For example, lizards are both less abundant and move less frequently as temperatures rise, making it more difficult for owls to spot and capture them (Flesch 2021, entire).

Based on moderate owl abundance and some decrease in habitat availability and connectivity, the northern Sonora analysis unit has a moderate level of population resiliency. Information from surveys and monitoring in 2021 in the northern Sonora analysis unit indicated a decline in pygmy-owl occupancy and an increase in habitat loss and fragmentation (Flesch 2021, pp. 12-14) and is evidence of decreasing resiliency in this analysis unit.

The western Mexico analysis unit is estimated to have tens of thousands of pygmy-owls. This analysis unit has some habitat fragmentation from urbanization, agricultural development, and deforestation of the tropical dry forests (Factor A). Overall, the western Mexico analysis unit has high population resiliency due to high abundance of pygmy-owls and generally healthy vegetation cover, likely as a result of higher levels of precipitation in the region than in other parts of the pygmy-owl's range.

The Texas analysis unit has an estimated pygmy-owl abundance in the high hundreds. Land ownership within this analysis unit has resulted in habitat fragmentation (Factor A) and, due to agricultural development and wood harvesting within the Rio Grande Valley, this analysis unit is somewhat genetically isolated from the rest of the geographic range of the subspecies (Factor E). Due to moderate pygmy-owl abundance, fragmentation of habitat, and some genetic isolation, the Texas analysis unit has a moderate level of population resiliency.

The northeast Mexico analysis unit is estimated to have tens of thousands of pygmy-owls. However, this unit has high levels of habitat fragmentation due to urbanization and agricultural development (Factor A). Overall, the northeast Mexico analysis unit has a moderate level of population resiliency with some capacity to withstand stochastic events. Rangewide, current condition of the pygmy-owl populations indicate that three analysis units are maintaining a moderate level of population resiliency, one analysis has low resiliency, and one analysis unit has high resiliency.

Representation

Resiliency, and the factors that drive resiliency, also contribute to the pygmy-owl's representation on the landscape. Pygmy-owls occupy a diversity of habitat types throughout the geographic range of the subspecies and maintain substantial genetic diversity. The subspecies' adaptive potential (representation) is currently high due to genetic and ecological variability across the range. There is substantial genetic diversity across the range (Proudfoot et al. 2006a, entire; 2006b, entire; Cobbold et al. 2022b, entire) due to isolation-by-distance and geographic barriers. Additionally, across the range, the pygmy-owl occupies a diverse range of ecological settings as a result of geographic gradients of vegetation, climate, elevation, topography, and other landscape elements. Such ecological diversity could help the pygmy-owl adapt to and survive future environmental changes, such as warming temperatures or decreased precipitation from climate change.

Redundancy

We assessed the number and distribution of population groups across the pygmy-owl's geographic range as a measure of its redundancy. While the abundance and densities of pygmy-owls are lower in some analysis units, these portions of the range still contribute in a meaningful way to the overall pygmy-owl population. Each analysis unit within the geographic range of the subspecies maintains a network of population groups that are connected both within and between analysis units. These population groups have the potential to recolonize areas where other population groups are lost to catastrophic events. All analysis units

contribute to the total rangewide population, and population groups within each analysis unit provide population support for that analysis unit and adjacent portions of the range. If an analysis unit is self-sustaining, it provides redundancy across the range, and may provide emigrants to support adjacent analysis units.

Exchange of individual cactus ferruginous pygmy-owls occurs among population groups within the Arizona, northern Sonora, and Texas analysis units, and between the Arizona and northern Sonora analysis units (Abbate et al. 2000, p. 30; Flesch and Steidl 2007, p. 37; Proudfoot et al. 2020, unpaginated; AGFD 2022, unpublished data). Habitat fragmentation and reduced vegetation health, as a result of ongoing drought and various land uses, have resulted in the extirpation of population groups in Arizona and Texas (Factor A), but redundancy was exhibited in the northern Sonora analysis unit when drought conditions eased and historically occupied areas were reoccupied (Flesch et al. 2017, p. 12). However, abundance has once again declined in northern Sonora and increased habitat loss and fragmentation likely are decreasing pygmy-owl habitat connectivity within this analysis unit and likely between the northern Sonora and Arizona analysis units (Factor A) because both analysis units are experiencing similar conditions (Flesch et al. 2017, entire; Flesch 2021, p. 9).

Despite existing habitat fragmentation, exchange of individual pygmy-owls occurs between population groups and between some analysis units is still occurring (Abbate et al. 2000, p. 30; Flesch and Steidl 2007, p. 37; Proudfoot et al. 2020, unpaginated; AGFD 2022, unpublished data). Habitat types used by pygmy-owls vary across the range, with some vegetation types being restricted to certain portions of the geographic range. It is important to maintain pygmy-owl populations throughout the range to provide redundancy to adjacent populations in similar habitat conditions. Due to the broad geographic distribution and network of population groups that are connected within and between some analysis units throughout most of its range, the pygmy-owl has some ability to recolonize following catastrophic events (Flesch et al. 2017, p. 12) and is considered to have adequate redundancy.

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Figure 1. Cactus ferruginous pygmy-owl's range in the United States and Mexico, including the five analysis units used in the species status assessment.

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Future Scenarios

In our SSA report, we defined viability as the ability of a species to sustain populations in the wild over time. To help address uncertainty associated with the degree and extent of potential future stressors and their impacts on species' needs, we assessed the principles of resiliency, redundancy, and representation using three plausible future scenarios that represent a reasonable range of outcomes that we expect could occur. We developed these scenarios by identifying information on the following primary factors anticipated to affect the cactus ferruginous pygmy-owl in the future: climate change, habitat loss and fragmentation, and ongoing conservation efforts (Flesch 2017, entire). The three scenarios capture the range of uncertainty in the changing landscape and how the pygmy-owl would likely respond to changing conditions.

We used the best available data and models to project out 30 years into the future (

i.e.,

2050). This is appropriate because, as we discuss later in the document, we define 30 years as the foreseeable future for our analysis of pygmy-owl viability and whether the species is a threatened species. We chose this timeframe based on the subspecies' lifespan and observed cycles in population abundance, as well as the time period where we could reasonably project certain land use changes and urbanization patterns relevant to the pygmy-owl and its habitat. The majority of existing projections of urbanization and population growth within the geographic range of the pygmy-owl extend to 2050. Because urbanization and development are some of the primary drivers of habitat loss and fragmentation, we extended our analysis as far as we could reasonably project these changes and the subspecies' response to those changes. Additionally, the average lifespan of a pygmy-owl is 3 to 5 years. Thus, over a 30-year timeframe, we would expect 8 to 10 generations of pygmy-owls to be produced, which should be an adequate amount to assess the long-term effects of both threats and conservation actions. Because the primary avenue through which pygmy-owls move across the landscape is through the dispersal of juveniles, it can take multiple generations to provide adequate exchange of individuals to elicit detectable changes at the population group and analysis unit scales. Including multiple generations of pygmy-owls also allows adequate time to account for lags in demographic factors resulting from changes in environmental conditions. Therefore, we conclude that this number of generations is sufficient to assess the effective levels of resiliency, redundancy, and representation.

Monitoring of pygmy-owl occupancy and productivity also indicates that, at least in Arizona and northern Sonora, 30 years is an adequate time period to document abundance cycles driven by climate conditions. Monitoring in both Arizona and northern Sonora from the mid-1990s to the present time showed a period of decline in occupancy and productivity, primarily due to drought, followed by an increase in productivity and occupancy during years of better precipitation such that abundance and occupancy recovered to nearly the original levels (Flesch et al. 2017, p. 12; Ingraldi 2020, pers. comm.; Service 2022a, entire). For more information on the models and their projections, please see the SSA report (Service 2022a, entire). Below, we also identify which of the five listing factors identified in the Act are influencing the pygmy-owl under each future scenario.

Under Scenario 1 (continuation of current trends), we projected no significant changes to the rate of habitat loss and fragmentation within the subspecies' range (Factor A). For this scenario, we considered that climate change would track Representative Concentration Pathway (RCP) 4.5, which is one of four alternative trajectories for carbon dioxide emissions set forth by the International Panel on Climate Change (IPCC 2014a, pp. 8-9). Specifically, RCP 4.5 is an intermediate scenario where carbon dioxide emissions continue to increase through 2040, but then stabilize and begin to decline. This scenario would result in atmospheric carbon dioxide levels between 580 and 720 parts per million (ppm) between 2050 and 2100, well above current rates of approximately 415 ppm, and would represent an approximately 2.5 °Celsius (C) increase in global mean temperature relative to the period 1861—1880 (IPCC 2014a, p. 9) (Factor E). We also considered that current conservation efforts, such as captive rearing, would continue to be limited in their efficacy, due to limited resources for agencies and other conservation partners to expand implementation. However, we would expect conservation efforts to improve modestly with continued efforts to identify appropriate and effective methodologies and protocols that mitigate the primary limitations to the success of releasing captive-reared pygmy-owls. Additionally, climate change will continue to affect the suitability of conditions at release sites (poor habitat conditions, reduced prey availability, etc.) for captive-reared pygmy-owls, likely limiting the effectiveness of pygmy-owl releases unless those effects can be mitigated through project protocols (Factor E).

Under these conditions, we do not anticipate that any of the factors used to evaluate resiliency would improve and, in fact, vegetation intactness would be reduced due to continued development (Factor A). Northeastern Mexico is projected to maintain its current level of pygmy-owl abundance because, relative to the current condition, substantial changes to habitat conditions are not expected, primarily because our analysis indicates reduced impacts from climate change on remaining habitat relative to other analysis units. Because of this, the northeastern Mexico analysis unit is expected to maintain a moderate level of population resiliency under this scenario. Conditions in the Arizona analysis unit would continue to decline due to continued habitat fragmentation and climate change (Factor A), and resiliency would remain low. Resiliency in the remaining three analysis units, northern Sonora, western Mexico, and Texas, would decline due to continued loss of pygmy-owl habitat, reduced habitat intactness, and a reduction in cover and prey availability for cactus ferruginous pygmy-owls (Factor A). Overall, current levels of population redundancy and representation would be maintained rangewide, but at a reduced rate. All analysis units would remain occupied; however, representation within each analysis unit would likely decline at the population-group scale.

Under Scenario 2 (worsening or increased effects scenario), we projected increased rates of habitat loss and fragmentation when compared to the current condition and over and above that projected under Scenario 1, leading to a decline in pygmy-owl habitat conditions (Factor A). For this scenario, we considered that climate change would track RCP 8.5, which is the highest greenhouse gas emission scenario. Under this scenario, atmospheric carbon dioxide concentrations are projected to exceed 1,000 ppm between 2050 and 2100 and would represent a 4.5 °C increase in global mean temperature (IPCC 2014a, p. 9) (Factor E). We also assumed that conservation efforts that are currently underway would not be effective or would not be implemented.

Increased habitat loss and fragmentation would result in the greatest effect on overall resiliency through a reduction in abundance and occupancy of pygmy-owls. Increased development and urbanization would result in increased permanent losses of habitat (Factor A). Indirect effects to vegetation and prey availability as a result of climate change would also occur (Factor E). Due to increased habitat fragmentation, such as agricultural development, as well as a reduction in vegetation health from drought (Factor A), resiliency in the western Mexico analysis unit is projected to decline. Under this scenario, climate change and increased habitat fragmentation from urbanization and agricultural development lead to the loss of some population groups within the Texas, Arizona, and northern Sonora analysis units (Factor A, Factor E). The resultant decline would decrease representation and redundancy within these analysis units. In particular, the Texas and Arizona analysis units would become more vulnerable to extirpation because of low

pygmy-owl abundance and occupancy driven by reduced habitat quality as a result of drought and high levels of habitat fragmentation from ongoing urbanization and agricultural development (Factor E, Factor A). Genetic representation would be reduced through the loss of population groups or analysis units and the subsequent reduction of gene flow (Factor E). Overall, there would be a reduction in resiliency, representation, and redundancy within most analysis units, and the likelihood of maintaining long-term viability would be considerably reduced.

Under Scenario 3 (improving or reduced effects scenario), we project that habitat loss and fragmentation would continue, but at a reduced rate (Factor A). For this scenario, we considered that climate change would track RCP 4.5 (Factor E), and conservation efforts that are currently underway would be effective. We did not include other planned conservation efforts in this scenario because we are not aware of any that would significantly influence the viability of the subspecies.

Despite effective conservation actions in portions of the range, the viability of pygmy-owl populations would continue to decline within all five analysis units due to the ongoing effects of habitat loss, fragmentation, and climate change (Factor A, Factor E). The positive effects of conservation actions would remain localized, and the negative effects of the ongoing threats would outweigh these local benefits to individual population groups at the scale of the entire analysis unit. Resiliency would remain low in the Arizona analysis unit and would decline in both the northern Sonora and western Mexico analysis units due to a reduction in habitat quality as a result of climate change (Factor E). We would expect pygmy-owl habitat fragmentation from urbanization, deforestation, and agricultural development (Factor A) to continue under this scenario, though at a slower rate because of increased efforts to address the impacts from climate change and to improve land use decisions, as well as implementing habitat-related conservation actions. Resiliency would remain in moderate condition for the Texas and northeastern Mexico analysis units. Although habitat conditions are expected to continue to decline due to drought and climate change (Factor E), we do not expect a large decline in pygmy-owl occupancy and abundance in Texas and northeastern Mexico. Under this scenario, each analysis unit remains occupied and contributes to the representation and redundancy across the range of the pygmy-owl. However, within each analysis unit, threats continue, albeit at a reduced rate, and the resiliency of population groups would decline in three of the five analysis units. Thus, within analysis units, representation and redundancy is likely to decrease at the population-group scale.

Cumulative Effects

We note that, by using the SSA framework to guide our analysis of the scientific information documented in the SSA report, we have analyzed not only individual effects on the subspecies but also their potential cumulative effects. We incorporate the cumulative effects into our SSA analysis when we characterize the current and future condition of the subspecies. To assess the current and future condition of the subspecies, we undertake an iterative analysis that encompasses and incorporates the threats individually and then accumulates and evaluates the effects of all the factors that may be influencing the subspecies, including threats and conservation efforts. Because the SSA framework considers not just the presence of the factors, but to what degree they collectively influence risk to the entire subspecies, our assessment integrates the cumulative effects of the factors and replaces a standalone cumulative effects analysis.

Conservation Efforts and Regulatory Mechanisms

In this section, we discuss regulatory mechanisms and conservation actions that potentially have influenced or will likely influence the current and future viability of the cactus ferruginous pygmy-owl.

Federal Protections

The pygmy-owl is protected under the Migratory Bird Treaty Act (MBTA) (16 U.S.C. 703-712). The MBTA prohibits “take” of any migratory bird. However, unlike the Act, there are no provisions in the MBTA preventing habitat destruction unless direct mortality or destruction of an active nest also occurs. Approximately 31 percent of the pygmy-owl's historical geographic range in the United States is federally owned, with federally-owned lands making up approximately 40 percent of pygmy-owl habitat in Arizona. However, a substantial extent of the known currently occupied habitat occurs on State Trust lands in Arizona and on private lands in Texas. Other Federal regulations and policies such as the Clean Water Act (33 U.S.C. 1251

et seq.

), the military's integrated natural resources management plans (INRMPs, such as the one for the Barry M. Goldwater Range) (Uken 2008, pers. comm.), and National Park Service policy provide varying levels of protection, but they have not, to this date, been effective in protecting the pygmy-owl from further decline as National Park Service owned lands comprise only a small portion of the range of the pygmy-owl.

Regulations under and implementation of the Clean Water Act help provide protections for a range of riparian habitat that is important to the pygmy-owl. Court actions and changes in regulations have decreased the potential scope of protections for riparian habitats within the range of the pygmy-owl. The 2006

Rapanos

Supreme Court decision restricts the linear extent of jurisdiction to watercourses having a “significant nexus” with a Traditionally Navigable Water. This means that after the Court's decision was implemented starting in 2008, fewer watercourses were deemed jurisdictional. This ruling has had the effect of further reducing past protections of riparian habitats. This limitation in the extent of federal jurisdiction particularly affected ephemeral streams in the pygmy-owl's Arizona habitat. Based on the individual approved jurisdictional determinations in Pima County by the U.S. Army Corps of Engineers, it is likely that most of the Avra-Altar system, which supports pygmy-owl occupancy, will be found to lack significant nexus to the Colorado River system, which means that these habitats will not receive the same analysis and protection that they received in the past under the Clean Water Act (Meltz and Copeland 2007, entire; Keith 2007, entire).

As a result of the implementation of the 2005 Real ID Act (Division B of Pub. L. 109-13), the U.S. Department of Homeland Security (DHS) has waived application of the Act and other environmental laws in the construction of border infrastructure, including areas occupied by the pygmy-owl (73 FR 5272, January 29, 2008). As recently as 2020, DHS waived environmental compliance for the construction of border walls along the U.S.-Mexico border in Arizona and Texas (Fischer 2019, unpaginated; USCBP 2020, unpaginated). Consequently, pygmy-owl habitat has been lost and fragmented along most of the border area in Arizona, as well as in Texas. Of particular concern is the potential for border infrastructure to reduce habitat connectivity into occupied pygmy-owl habitat in Mexico (Flesch et al. 2010, pp. 177-179).

State Protections

The pygmy-owl is included on the State of Arizona's list of species of concern (AGFD 2021a, p. 16). Arizona statutes (ARS Title 17) only protect individual pygmy-owls and their nests or eggs and do not address destruction or alteration of pygmy-owl habitat. The State of Texas lists the pygmy-owl as threatened (Texas Administrative Code, title 31, part 2, chapter 65, subchapter G, rule 65.175; TPWD 2009, unpaginated; TPWD 2022, unpaginated). This designation allows permits to be issued for the taking, possession, propagation, transportation, sale, importation, or exportation of pygmy-owls if necessary to properly manage that species but, similar to Arizona, does not provide any habitat protections (Texas Park and Wildlife Code, chapter 67, section 67.0041).

Texas and Arizona state law prohibit any take (incidental or otherwise) of state-listed or protected species. In both states, species may only be handled by persons possessing a scientific activity permit, scientific permit for research, or other form of authorization from the State. While state laws in both Texas and Arizona prohibit the capture, trap, take, or kill, or attempt to capture, trap, take, or kill of protected wildlife, like the pygmy-owl, they provide no protection to their habitats.

Protections in Mexico

Within Mexico, the distribution of owls is large and includes multiple States. The administration of land use in Mexico depends on the national government, which implements Natural Protected Areas and other Federal programs, and also the policies of each State and even municipal governments (Enríquez 2021, pers. comm.). This system represents a wide range of management, conservation, and natural resource use approaches that affect pygmy-owl conservation, resulting in inconsistent policies and inconsistent implementation of conservation activities. No laws or regulations in Mexico specifically protect pygmy-owls and pygmy-owl habitat. Further complicating the conservation of the pygmy-owl in Mexico is the sheer diversity of entities involved in managing land use in Mexico, each with its own mission, goals, and objectives, many of which are not related to natural resource conservation. Thus, development and application of regulations and land-management activities that promote the conservation of pygmy-owls in Mexico is difficult and exceedingly complicated (Enríquez 2021, pers. comm.).

Conservation Efforts

Cactus ferruginous pygmy-owl conservation activities have occurred sporadically over the past three decades in both the United States and in northern Sonora in Mexico. Initial conservation efforts developed effective and safe protocols for studying the cactus ferruginous pygmy-owl and on gathering basic life-history information. Efforts expanded in the late 1990s and early 2000s to include important pygmy-owl work in Arizona, Texas, and northern Sonora. For the past two decades, studies have been irregular and focused primarily on monitoring known territories, although work continues on the pygmy-owl captive-breeding pilot project, as described below.

Surveying and Monitoring

AGFD initiated surveys to determine the extent of cactus ferruginous pygmy-owl occurrences in Arizona in 1992, when the cactus ferruginous pygmy-owl was first petitioned to be listed under the Act. Survey and monitoring work by a variety of entities continued through 2006, when the subspecies was delisted. Prior to delisting, survey and monitoring efforts were focused within Pima and Pinal Counties to document the occupancy pattern of cactus ferruginous pygmy-owls in areas of land use changes, primarily urban development. After the pygmy-owl was delisted in 2006, Service and AGFD biologists continued to conduct a small number of monitoring surveys. In 2020, AGFD coordinated a comprehensive survey effort within the recently occupied areas of Arizona, with the help of numerous partners, to gather data on the current abundance and distribution of the cactus ferruginous pygmy-owl in Arizona to inform this listing decision. Specifically, this effort included surveys to document distribution, territory occupancy monitoring, and some nest searches to document reproduction. This latest effort provided data on current distribution of the pygmy-owl in Arizona and the number of occupied territories, as well as some information on the number of active nesting territories (Ingraldi 2020, pers. comm.; AGFD 2021b, pers. comm.). These data are incorporated into the SSA report. However, these efforts did not provide any information on productivity or survival at these sites. Despite the changing regulatory environment and inconsistent availability of resources, survey and monitoring activities provide important information on the abundance and distribution of pygmy-owl across its range and, with that information, managers can more effectively and efficiently work to conserve the pygmy-owl.

Nest Box Trials

Because cactus ferruginous pygmy-owls are secondary cavity nesters (birds that nest in cavities excavated by other bird species), the number of available cavities may influence the viability of cactus ferruginous pygmy-owls on the landscape (Proudfoot 1996, p. 68). Using nest boxes as a management tool may enhance the viability of cactus ferruginous pygmy-owls by increasing cavity availability and reducing predation. Nest boxes also enhance access to the owls during nesting, which facilitates research. Research in Texas demonstrated successful use of artificial nest structures by cactus ferruginous pygmy-owls (Proudfoot et al. 1999, pp. 5-6). In response to concerns about cavity availability, two nest box trials were conducted in Arizona in 1998 and 2006. No cactus ferruginous pygmy-owls used the nest boxes in these studies, but low cavity availability was confirmed based on high use of the nest boxes by other species, including screech owls. No additional nest box studies have been undertaken in Arizona, and the nest box study in Texas is no longer active. The information on nest box use in Texas has contributed to the conservation of the pygmy-owl in Texas. Additional research is needed in other parts of the pygmy-owl's range to understand the effectiveness, or lack thereof, of using nest boxes as a conservation tool for pygmy-owls.

Captive-Breeding and Population Augmentation

The AGFD initiated a pygmy-owl captive-breeding feasibility study in partnership with the Wild at Heart raptor care facility in Cave Creek, Arizona, in 2006. Since then, Wild at Heart has researched and tested protocols for a managed breeding program for cactus ferruginous pygmy-owls. In 2017, the Phoenix Zoo became the second captive-breeding site for pygmy-owls in Arizona and part of the managed breeding program when it entered into partnership with the Service and the AGFD. Both the AGFD and the Service oversee this program.

The goal of the managed breeding program for the cactus ferruginous pygmy-owl is to develop appropriate protocols for the husbandry and breeding of captive pygmy-owls to provide individuals to augment existing population groups or establish new population groups in areas where suitable habitat exists in Arizona (AGFD 2015, entire). To date, these efforts have

demonstrated: (a) Successful capture and transport of wild cactus ferruginous pygmy-owls; (b) safe, healthy, and stress-free captive facilities; (c) the development of appropriate care, feeding, and maintenance protocols; (d) successful breeding; and (e) appropriate care and development of young-of-the-year birds. Three pilot releases of captive-bred pygmy-owls have been implemented since the inception of this program. This effort establishes the first formal captive-breeding for the subspecies and provides the groundwork for evaluation of this strategy in wild cactus ferruginous pygmy-owl population augmentation. These pilot releases have not resulted in the establishment of new pygmy-owl territories or population groups, but they have contributed valuable information to developing appropriate release strategies and protocols to improve the potential for conservation benefits to the pygmy-owl in the future. For example, high mortality rates of released captive-bred pygmy owls as a result of weather, prey availability, predation, habitat conditions, and lack of pre-release conditioning all likely contributed to past failures. However, an adaptive management approach is being used to address such mortality factors and improve methodology. The partners involved in this project are committed to the continuation of this effort into the future.

Conservation Planning

When the pygmy-owl was listed previously, several municipalities located within current or historical pygmy-owl activity areas explored or implemented habitat conservation plans (HCPs) under the Act to address potential conflicts between development projects and requirements of the Act. These HCP plans included the Sonoran Desert Conservation Plan (Multi-Species Conservation Plan) developed by Pima County (Pima County 2016, entire), the Town of Marana HCP (Town of Marana 2009, entire), and the City of Tucson's Avra Valley (City of Tucson 2019, entire) and Southlands HCPs (City of Tucson 2013, entire). Each of these four HCP efforts identified the cactus ferruginous pygmy-owl as one of the covered species within their plans. However, most of these plans have yet to be completed: to date, only the Pima County HCP has been completed and implemented. Pima County is currently conducting ongoing surveys and monitoring of pygmy-owl territories on county-managed lands and has set aside pygmy-owl habitat as part of their conservation-lands system in compliance with their HCP. The establishment of these conservation lands is an important contribution to pygmy-owl conservation in Pima County, but continuing efforts are needed to address other threats such as habitat impacts from climate change. Pima County's efforts are expected to continue for the 30-year life of their permit (through 2046) and longer if the County renews the permit.

Another ongoing conservation planning effort that has the potential to support pygmy-owl conservation in the Altar Valley of southern Arizona is the Altar Valley Watershed Management Plan. This plan (being developed by the Altar Valley Conservation Alliance with numerous partners and participants) builds upon existing efforts within the Altar Valley to restore and enhance the watershed. The plan will describe stewardship practices and identify a series of high-priority projects that maximize positive impacts on the land. Projects related to watershed restoration have already been implemented at three ranches in the Altar Valley. These projects have included one-rock dams and other structures to stabilize waterways, road grading to promote water harvesting, and enhancement of grasslands through invasive species control to promote infiltration and reduce runoff and sedimentation. These actions improve vegetation health through increased water infiltration and reduced loss of soil and vegetation due to erosion. These benefits improve riparian vegetation along drainages enhancing pygmy-owl habitat conditions and connectivity. Ranches within the Altar Valley of southern Arizona have maintained open space and contributed to the conservation of pygmy-owls for over 20 years. Overall, the conservation planning efforts implemented to date have contributed to the conservation of the pygmy-owl through protecting or enhancing important pygmy-owl habitat in Arizona and providing a path towards long-term habitat viability and maintenance.

In Mexico, Federal, State, and municipal protected areas comprise approximately 11 percent of the historical pygmy-owl range in Mexico. These areas can work well as conservation strategies for the cactus ferruginous pygmy-owl. There is now a new option for protected areas called Voluntary Conservation Areas (Áreas Destinadas Voluntariamente a la Conservación; ADVA), which are areas identified for conservation. These ADVA could be a potential conservation strategy for the pygmy-owl in the future with improved design, management, and enforcement (Burquez and Martinez-Yrizar 1997, p. 378; Valdez et al. 2006, p. 272; Burquez and Martinez-Yrizar 2007, p. 546; Enríquez 2021, pers. comm.).

Summary of Comments and Recommendations

In the proposed rule published on December 22, 2021 (86 FR 72547), we requested that all interested parties submit written comments on the proposal by February 22, 2022. We also contacted appropriate Federal and State agencies, scientific experts and organizations, and other interested parties and invited them to comment on the proposal. Newspaper notices inviting general public comment were published in the Arizona Daily Star and Corpus Christi Caller-Times. We held a public hearing on January 25, 2022. All substantive information received during comment periods has either been incorporated directly into this final determination or is addressed below.

Peer Reviewer Comments

As discussed in Peer Review above, we received comments from three peer reviewers. We reviewed all comments we received from the peer reviewers, including comments on substantive issues and new information contained in the SSA report. The peer reviewers generally concurred with our methods and conclusions, and provided additional information, clarifications, and suggestions to improve the final SSA report. Peer reviewer comments are addressed in the following summary and were incorporated into the final SSA report as appropriate.

(1) Comment:

One peer reviewer commented that the construction of the border wall will cause substantive ecological damage and function as a barrier to many terrestrial animals. However, the peer reviewer finds the idea that the border wall would be an impediment or barrier to pygmy-owls to be unfounded.

Our response:

No studies have specifically looked at how border walls and associated infrastructure may affect pygmy-owl movements. We do not currently know if these structures will be a barrier or an impediment on pygmy-owls. However, observations in the field indicate that barriers similar to the border wall may affect pygmy-owl movement patterns. Pygmy-owl flight patterns are generally less than 30 m (100 ft) and typically only 1.5 to 3.0 m (5 to 11 ft) above the ground (Flesch and Steidl 2007, p. 35; AGFD 2008, pers. comm.). Flesch et al. (2010, pp. 7-9) show that the vegetation gaps, in association with the tall fences, may limit transboundary movements by pygmy-owls. The fences and vehicle

barriers along the border, when considered in conjunction with patrol roads, drag roads, and vegetation removal, result in a combination of unvegetated area with a raised structure in the middle causing an impediment to pygmy-owl movement. Observations reported in the literature show that pygmy-owls avoid crossing open areas associated with roadways (Abbate et al. 1999, p. 54; Flesch and Steidl 2007, pp. 6-7; Flesch 2017, p. 5; Flesch et al. 2017, entire; Flesch 2021, pp. 12-14). Given other known impediments to pygmy-owl movements, it is likely border infrastructure could affect cross-border movements by pygmy-owls, at least at some border locations. The SSA report discusses factors that logically could result in some impact to pygmy-owl cross-border movements. However, pygmy-owls are capable flyers and easily navigate small openings in their normal day-to-day behaviors. Pygmy-owls are sometimes observed very high in trees, at or above the height of border infrastructure. Therefore, the border wall itself may not affect all cross-border movements, depending on the crossing site characteristics. However, the border wall in conjunction with lighting, patrol and interdiction activities, and vegetation clearing present more factors potentially deterring pygmy-owl movements. This issue needs more research and monitoring to determine whether and how such border infrastructure affects pygmy-owl movements.

(2) Comment:

A peer reviewer expressed concern in considering the eastern and western populations to be the same subspecies. The peer reviewer expressed concerns about considering each of these to be redundant populations because, with no evidence of interchange between the two populations, each population would be unable to provide rescue to the other population.

Our response:

This issue was investigated by Proudfoot et al. (2006a, entire; 2006b, entire) and König et al. (1999, entire), who concluded the eastern and western populations may comprise two separate subspecies. This information, in combination with the historical descriptions of distributions for the subspecies

cactorum,

as discussed in the SSA report, provided some general evidence that reclassification of this subspecies could have merit. However, after reviewing the best available information, we find that the evidence of delineating the range of these subspecies is uncertain and inconsistent. Peer reviewers of our 2011 12-month finding pointed out that a combination of factors, including morphological, vocal, and genetic, need to be considered in greater depth, with additional sampling and analysis of existing samples, to determine if the petitioned taxonomic classification should be accepted, and we are in agreement with these comments.

Given the uncertainty and lack of clarification found in the best available scientific and commercial information, we rely on the “biological expertise of the Department and the scientific community concerning the relevant taxonomic group” (50 CFR 424.11(a)) and the “standard taxonomic distinctions (50 CFR 424.11(a)). Additional genetic sampling and analysis in 2021 through AGFD, while providing additional samples and an updated analysis of Proudfoot et al.'s (2006a, entire, and 2006b, entire) work, did not provide compelling evidence to change our conclusions regarding the taxonomic classification of the cactus ferruginous pygmy-owl (Cobbold et al. 2022b, entire) (see also Background above). We do not yet have enough information to say whether pygmy-owls at the far ends of their distribution (Texas and Arizona) represent different subspecies, but the work by Cobbold et al. (2022b, entire) suggests there is likely some degree of redundancy between the eastern and western populations of the pygmy-owl at the southern end of the range. In other words, cactus ferruginous pygmy-owls in the southern portion of the range are more similar to each other than to pygmy-owls in the northern extremes of the range in Arizona and Texas. See also our response to comment 8 below.

(3) Comment:

One peer reviewer pointed out that the influence diagram in the SSA report (figure 4.1) was missing some linkages and suggested careful consideration of additional linkages that may need to be added.

Our response:

We acknowledge that there are numerous other connections not shown in the influence diagram in the SSA report. However, we have simplified the graphic to illustrate the most important influences on the subspecies. We have added the two additional connections suggested by the reviewer and added clarification in the SSA report acknowledging the complicated and interconnected nature of stressors, habitat, individuals, and population resiliency.

Federal Agency Comments

(4) Comment:

The Forest Service stated that a critical habitat designation would help to define areas in which to restrict wood harvesting within the Coronado National Forest.

Our response:

We will be publishing a proposed rule to designate critical habitat as a separate action and will solicit public comments on the critical habitat designation at that time. Our intent is to publish a proposed critical habitat rule within 1 year of this final listing rule.

Comments From States

(5) Comment:

The Arizona Department of Forestry and Fire Management and the Arizona Department of Transportation expressed concerns about prohibitions on prescribed fire in the Sonoran Desert and thinning of woody plants, specifically as it relates to fire management, invasive species management, and for public safety along roadways. The Arizona Department of Transportation requested that vegetation management and brush removal within the recovery zone of roads and other strategic locations be included as an exception in the 4(d) rule.

Our response:

We acknowledge and understands the importance of managing vegetation strategically along roadways and for fire and invasive species management that can promote the conservation of native species and their habitats. However, a broad exception under a 4(d) rule for such activities would prevent us from working with partners to conduct these activities in a way that minimizes effects to the pygmy-owl and its habitat. The design of projects such as these are dependent upon a number of site-specific factors requiring unique recommendations and approaches so that pygmy-owl-specific measures can be incorporated. We have a number of tools in place to reduce consultation workloads for action agencies, including programmatic consultations, which would allow for strategic planning of vegetation projects while allowing adequate planning and review. We look forward to the opportunity to work collaboratively with partners in Arizona and Texas to help conduct necessary vegetation management projects while also ensuring that effects to listed species are considered and minimized.

(6) Comment:

The Texas Parks and Wildlife Department (TPWD) and Arizona Department of Transportation requested increased clarification for which habitat restoration projects would be excepted under the 4(d) rule.

Our response:

We have provided additional clarity for which habitat projects are excepted under the 4(d) rule and which would require a section 7 consultation. This additional clarification can be found under Provisions of the 4(d) Rule below.

(7) Comment:

The TPWD requested additional information regarding the potential to use the State permitting process for surveying and monitoring activities.

Our response:

Discussion of this issue with TPWD has revealed they are only authorized to permit activities that involve direct handling of protected species, and, therefore, they do not permit the types of activities excepted under the 4(d) rule for pygmy-owls, according to Texas State Parks and Wildlife Code (Sec. 43.021). For this reason, we will still require a Federal section 10 permit for pygmy-owl activities in Texas.

(8) Comment:

The Texas Comptroller of Public Accounts and the AGFD questioned the validity of the subspecies' taxonomy and stated that the Service should first address the taxonomic uncertainty prior to making a listing decision.

Our response:

As discussed in Background and

Peer Reviewer Comments,

above, and extensively in the SSA report (Service 2022a, Section 2.1-2.2), we rely on the currently accepted taxonomy when making listing decisions. Although there have been proposed revisions to the pygmy-owl taxonomy, these revisions have not been accepted by the American Ornithological Society, the recognized authority for avian taxonomic classification. Therefore, we have analyzed the cactus ferruginous pygmy-owl as currently described (

Glaucidium brasilianum cactorum

).

(9) Comment:

The Texas Comptroller of Public Accounts stated that pygmy-owl habitat in Texas makes up only five percent of the range of the subspecies and that the population there is most likely secure. They also state that the population in Texas is greater than that of Arizona.

Our response:

When analyzing the status of a species throughout its range, we do not focus only on the portions of the species' range within one State. Therefore, the percentage of the range within each State in a species' range is not directly relevant to its status throughout its range. We agree that the population in Texas is likely greater than that in Arizona and have acknowledged that fact in this rule. Although populations in one State may be higher than another, we analyze the status of the species throughout all or a significant portion of its range when making listing decisions. We rely on the current and future conditions, and the threats and stressors acting on the species and its habitat, to determine whether or a not a species is in danger now or likely to become endangered in the foreseeable future throughout all, or a significant portion of its range, not within each State in which it occurs. Although pygmy-owls in Texas still occur within rural private lands, much of the range of the pygmy-owl in Texas has been developed and connectivity to Mexico has been significantly reduced. The pygmy-owl has been listed as a Species of Greatest Conservation Need by TPWD since 2005, and in 2020, TPWD downgraded the ranking of the subspecies from vulnerable to imperiled. TPWD, the State authority for managing the wildlife in Texas, was closely involved in the development of the SSA for the pygmy-owl and provided data for this species in Texas. For these reasons, we do not conclude that the species is secure in Texas for the foreseeable future.

(10) Comment:

The Texas Comptroller of Public Accounts stated that the information used in the SSA report may have been best available but was incomplete and outdated. They stated that the Service should not make a listing decision without robust population and habitat data.

Our response:

When making listing decisions, we are required to rely on the best available information. The Act does not require that we conduct our own research and monitoring before making a listing determination. Often, we are required to make listing decisions based on incomplete or outdated information, as many of the species we analyze are rare and it is difficult to get adequate sample sizes for study or analysis. For these reasons, many of these species are not thoroughly studied. We do not delay providing protections to species while awaiting additional data and, while we would welcome new information not included in our SSA report, to date our analysis includes the best available information for the pygmy-owl.

(11) Comment:

The AGFD and other commenters stated that the Service did not provide adequate support linking projected future human population growth to direct effects to the status of the pygmy-owl. The commenters stated that the Service needed direct information related to the subspecies' status before, during, and after this human population growth to demonstrate an effect to the subspecies.

Our response:

We acknowledge that we do not have an extensive set of quantified empirical data for a detailed analysis of the effects of urbanization and development on pygmy-owls and pygmy-owl habitat. There have been no specific studies quantifying the effects to pygmy-owls and their habitat from urban development. However, as presented in Appendix 6 of the SSA Report (Service 2022a, Appendix 6), the data we have indicate that substantial areas of habitat within the range of the pygmy-owl have been lost due to urban growth and development (approximately 100,000 acres cumulatively in the Arizona and Texas analysis units over the past 10 years), and it is reasonable to predict that such loss will continue as population growth and development patterns trend upward into the future and more suitable habitat is converted for urban development. We used the best available information on population growth and development projects to project potential losses of pygmy-owl habitat into the future.

Additionally, in response to a comment we received during the public comment period, we completed additional analysis on land cover changes within pygmy-owl habitat in Texas and Arizona over the past decade (2010-2020). The commenter provided an analysis on changes in land cover within the pygmy-owl analysis areas during the time period of 2010-2015 and suggested that the impacts to pygmy-owl habitat were not as great as we presented in the proposed rule and SSA report. The commenter's data sources were different than what we used in the SSA, but the commenter presented a reasonable issue with regard to the data presented. Because it is important to consider the scope, scale, and the factors included in different sources of data, we conducted additional analysis using data sources that provided the same type of data that the commenter used in their analysis. This allowed us to compare the results of additional sources of data with the results presented by the commenter. This additional analysis provides different results than presented by the commenter, but this outcome is expected because of differing time periods, categories of land cover and land use, and the scope and scale of the data.

Both analyses provide useful information to consider as we evaluate the status of the pygmy-owl. Neither analysis changed the outcome of our listing decision or our assessment of the effects of human population growth on the pygmy-owl. Our analysis showed greater impacts to pygmy-owl habitat than the data provided by the commenter and supported our finding that some areas of pygmy-owl habitat have been lost or modified and habitat fragmentation has continued, at least in Texas and Arizona, during this time period. Our further analysis related to the impacts of various land uses on pygmy-owl habitat over the past decade

can be found in appendix 6 of the SSA report (Service 2022a, appendix 6).

(12) Comment:

The AGFD claimed that agricultural development should not be considered a current threat to the pygmy-owl in Arizona as the effects of agricultural development occurred primarily historically.

Our response:

Agricultural development was primarily a historical threat to the distribution of pygmy-owls in Arizona (Stromberg 1993, pp. 117-119; Jackson and Comus 1999, pp. 215-255). However, agricultural development is still a local impact to pygmy-owls in Arizona and is impacting habitat connectivity and pygmy-owl movements in some parts of Arizona, primarily in Pima and Pinal Counties (Service 2022a, Appendix 6). Additionally, agricultural development is currently resulting in ongoing pygmy-owl habitat loss and fragmentation in Texas and in all the analysis units in Mexico. The best available information indicates it is a current and projected threat to pygmy-owl habitat.

Public Comments

(13) Comment:

One commenter stated that the Service did not explain why the proposed 4(d) rule was not analyzed under the National Environmental Policy Act.

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