Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for Southwestern Willow Flycatcher

DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R2-ES-2011-0053; 4500030114]

RIN 1018-AX43

Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for Southwestern Willow Flycatcher

AGENCY:

Fish and Wildlife Service, Interior.

ACTION:

Final rule.

SUMMARY:

We, the U.S. Fish and Wildlife Service (Service), designate revised critical habitat for the southwestern willow flycatcher (

Empidonax traillii extimus

) (flycatcher) under the Endangered Species Act. In total, approximately 1,975 stream kilometers (1,227 stream miles) are being designated as critical habitat. These areas are designated as stream segments, with the lateral extent including the riparian areas and streams that occur within the 100-year floodplain or flood-prone areas encompassing a total area of approximately 84,569 hectares (208,973 acres). The critical habitat is located on a combination of Federal, State, tribal, and private lands in Inyo, Kern, Los Angeles, Riverside, Santa Barbara, San Bernardino, San Diego, and Ventura Counties in California; Clark, Lincoln, and Nye Counties in southern Nevada; Kane, San Juan, and Washington Counties in southern Utah; Alamosa, Conejos, Costilla, and La Plata Counties in southern Colorado; Apache, Cochise, Gila, Graham, Greenlee, La Paz, Maricopa, Mohave, Pima, Pinal, Santa Cruz, and Yavapai Counties in Arizona; and Catron, Grant, Hidalgo, Mora, Rio Arriba, Socorro, Taos, and Valencia Counties in New Mexico. The effect of this regulation is to conserve the flycatcher's habitat under the Endangered Species Act.

DATES:

This rule becomes effective on February 4, 2013.

ADDRESSES:

This final rule is available on the Internet at

http://www.regulations.gov

, Docket No. FWS-R2-ES-2011-0053. Comments and materials received, as well as supporting documentation used in preparing this final rule, are available for public inspection, by appointment, during normal business hours, at the U.S. Fish and Wildlife Service, Arizona Ecological Services Office, 2321 West Royal Palm Rd., Suite 103, Phoenix, AZ 85021; telephone 602-242-0210; facsimile 602-242-2513.

The coordinates or plot points or both from which the critical habitat maps are generated are included in the administrative record for this critical habitat designation and are available at

http://www.fws.gov/southwest/es/arizona

,

www.regulations.gov

at Docket No. FWS-R2-ES-2011-0053, and at the Arizona Ecological Services Office (see

FOR FURTHER INFORMATION CONTACT

). Any additional tools or supporting information that we may develop for this critical habitat designation will also be available at the Fish and Wildlife Service Web site and Field Office set out above, and may also be included in the preamble or at

http://www.regulations.gov

.

FOR FURTHER INFORMATION CONTACT:

Steve Spangle, Field Supervisor, U.S. Fish and Wildlife Service, Arizona Ecological Services Office, 2321 West Royal Palm Rd., Suite 103, Phoenix, AZ 85021; telephone 602-242-0210; facsimile 602-242-2513. If you use a telecommunications device for the deaf (TDD), call the Federal Information Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Executive Summary

Why we need to publish a rule.

This is a final rule to revise the designation of critical habitat for the southwestern willow flycatcher (flycatcher). Under the Endangered Species Act (Act), any species that is determined to be an endangered or threatened species requires critical habitat to be designated, to the maximum extent prudent and determinable. Designations and revisions of critical habitat can only be completed by issuing a rule.

The revised critical habitat areas we are designating in this rule constitute our current best assessment of the areas that meet the definition of flycatcher critical habitat. In total, we are designating as flycatcher critical habitat approximately 1,975 stream kilometers (km) (1,227 stream miles (mi)) encompassing a total area of approximately (84,569 hectares (ha), (208,973 acres (ac)) in 24 Management Units.

We have prepared an economic analysis and environmental assessment for the designation of critical habitat.

In order to consider economic impacts, we have prepared an analysis of the economic impacts of the critical habitat designations and related factors. The purpose of the environmental assessment, prepared pursuant to the National Environmental Policy Act (NEPA), is to identify and disclose the environmental consequences resulting from the proposed action of designating revised critical habitat for the flycatcher. We announced the availability of the draft economic analysis and draft environmental assessment in the

Federal Register

on July 12, 2012 (77 FR 41147), allowing the public to provide comments on our analyses. We have considered the comments and have completed the final economic analysis and final environmental assessment concurrently with this final determination.

Peer review and public comment.

We sought comments from independent specialists to ensure that our designation is based on scientifically sound data and analyses. We obtained opinions from four knowledgeable individuals with scientific expertise to review our technical assumptions, analysis, and whether or not we had used the best available information. These peer reviewers generally concurred with our methods and conclusions and provided additional information, clarifications, and suggestions to improve this final rule. Information we received from peer review is incorporated in this final revised designation. We also considered all comments and information received from the public during the comment period.

Previous Federal Actions

The flycatcher was listed as endangered under the Act (16 U.S.C. 1531

et seq.

) on February 27, 1995 (60 FR 10694). On July 22, 1997, we published a final critical habitat designation for the flycatcher along 964 river km (599 river mi) in Arizona, California, and New Mexico (62 FR 39129). We published a correction notice on August 20, 1997, on the lateral extent of critical habitat (62 FR 44228).

As a result of a 1998 lawsuit from the New Mexico Cattle Growers' Association, on October 19, 2005 (70 FR 60886), we published a revised final flycatcher critical habitat rule for portions of Arizona, California, New Mexico, Nevada, and Utah, totaling approximately 48,896 ha (120,824 ac) or 1,186 km (737 mi). River segments were designated as critical habitat in 15 of the 32 Management Units described in the Recovery Plan (Service 2002, p. 63).

We were sued by the Center for Biological Diversity over our 2005 critical habitat rule, and on July 13, 2010, we agreed to redesignate critical habitat. The resulting settlement left the existing critical habitat designation from 2005 in effect. We proposed a flycatcher critical habitat revision on August 15, 2011 (76 FR 50542), and additional

proposal information was included in our July 12, 2012 (77 FR 41147), rule reopening the comment period. We requested and received an extension to allow a final rule to be delivered to the

Federal Register

by December 14, 2012.

Background

Additional background information on the flycatcher, beyond what is provided below, can be found in the proposed revision of flycatcher critical habitat published on August 15, 2011 (76 FR 50542), as well as the final flycatcher critical habitat rule published in the

Federal Register

on October 19, 2005 (70 FR 60886); our October 12, 2004, proposed critical habitat rule (69 FR 60706); the Southwestern Willow Flycatcher Recovery Plan (Recovery Plan) (Service 2002, entire); our first flycatcher critical habitat designation, published July 22, 1997 (62 FR 39129), and August 20, 1997 (62 FR 44228); the final flycatcher listing rule (60 FR 10694, February 27, 1995); the 10-year flycatcher study in central Arizona (Paxton

et al.

2007, entire); the 2007 rangewide status report (Durst

et al.

2008, entire); and flycatcher survey protocol and natural history summary (Sogge

et al.

2010, entire). Other reports can be retrieved from the U.S. Geological Survey's (USGS) flycatcher site at

http://sbsc.wr.usgs.gov/cprs/research/projects/swwf

.

Taxonomy

The flycatcher, from the taxonomic order Passeriformes, is one of four subspecies of the willow flycatcher currently recognized (Hubbard 1987, pp. 3-6; Unitt 1987, pp. 137-144), although Browning (1993, p. 248) suggests a possible fifth subspecies (

Empidonax traillii campestris

) in the central and midwestern United States.

Species Description

The flycatcher is a small, insect-eating generalist (Service 2002, p. 26), neotropical migrant bird. It grows to about 15 centimeters (5.8 inches) in length. It eats a wide range of invertebrate prey including flying, and ground- and vegetation-dwelling, insect species of terrestrial and aquatic origins (Drost

et al.

2003, pp. 96-102). The flycatcher spends the winter in locations such as southern Mexico, Central America, and probably South America (Ridgely and Gwynne 1989, p. 303; Stiles and Skutch 1989, pp. 321-322; Howell and Webb 1995, pp. 496-497; Unitt 1997, pp. 70-73; Koronkiewicz

et al.

1998, p. 12; Unitt 1999, p. 14).

Distribution

The known geographical area historically occupied by migrating and breeding flycatchers includes southern California, southern Nevada, southern Utah, southern Colorado, Arizona, New Mexico, western Texas, and extreme northwestern Mexico (Hubbard 1987, pp. 6-10; Unitt 1987, pp. 144-152; Browning 1993, pp. 248, 250). The flycatcher's current range is similar to the historical range, but the quantity of suitable habitat within that range is reduced from historical levels (Service 2002, pp. 7-10). Flycatchers nest within the southwestern United States from about May to September (Sogge

et al.

2010, p. 11).

At the time of listing in February 1995 (60 FR 10694), the distribution and abundance of nesting flycatchers, their natural history, and areas occupied by breeding, nonbreeding, migrating, and dispersing flycatchers were not well known. In February 1995, 359 breeding territories were known only from California, Arizona, and New Mexico. Unitt (1987, p. 156) estimated the entire population was “well under a 1000 pairs, more likely 500,” and 230 to 500 breeding territories (see definition below) were estimated to exist in the July 23, 1993, flycatcher listing proposal (58 FR 39495, p. 39498).

At the end of 2007, 1,299 flycatcher breeding territories were estimated to occur throughout southern California, southern Nevada, southern Utah, southern Colorado, Arizona, and New Mexico (Durst

et al.

2008, p. 4). Some of the flycatcher breeding sites (see definition below) having the highest number of territories are found along the middle Rio Grande and upper Gila River in New Mexico, and Roosevelt Lake and the San Pedro and Gila River confluence area in central Arizona.

A breeding site is simply an area along the river that has been described while surveying for flycatcher territories (Service 2002, p. C-4; Sogge

et al.

2010, p. 34). A breeding site can contain none, only one, or many territories. However, within this final rule, we refer to breeding sites as areas where flycatcher territories were detected. A territory is defined as a discrete area defended by a single flycatcher or pair of flycatchers within a single breeding season (Sogge

et al.

2010, p. 34). The territory is usually evidenced by the presence of a singing male, and possibly one or more mates (Sogge

et al.

2010, p. 34). When we discuss locations occupied by flycatchers, those are locations not just of those areas used as breeding territories, but also of those areas used by foraging, migrating, and dispersing flycatchers for food, cover, and shelter.

At the time of listing, breeding sites in California, Nevada, Utah, and Colorado described by Unitt (1987, pp. 149-152) were adopted as the subspecies' northern boundary. However, the collection and analysis of genetic material across this part of the flycatcher's range has since refined this boundary (Paxton 2000, pp. 3, 18-20), and reduced the extent of the northern boundary of the southwestern subspecies in Utah and Colorado (Service 2002, Figure 3). Territories once believed to be held by southwestern willow flycatchers in Utah and Colorado are now more accurately known to be occupied by a different, non-listed willow flycatcher subspecies. As a result, the southwestern subspecies' range only occurs in the southernmost portions of Utah and Colorado. This genetic work also confirmed the identity of southwestern willow flycatcher subspecies throughout the rest of its range.

The USGS has continued to collect genetic information to help refine the northern boundary of the subspecies' range in Utah, Colorado, and New Mexico (Paxton

et al.

2007a, entire). They reconfirmed the genetic markers that identify differences among flycatcher subspecies, with breeding sites clustering into two groups separated approximately along the currently recognized boundary; however, they noted a distinct genetic boundary line between the subspecies does not exist (Paxton

et al.

2007a, p. 17). Instead of a distinct boundary, they suggested that the boundary should be thought of as a “region of genetic overlap” (Paxton

et al.

2007a, p. 17). They also described that this genetic overlap region will likely widen and contract over time based upon habitat changes (Paxton

et al.

2007a, p. 17). An additional complication in refining the subspecies' northern boundary is that this region is sparsely populated with breeding flycatchers, and therefore only minimal information is available that would help narrow down the location of a boundary (Paxton

et al.

2007a, p.16). We continue to seek out territories and collect genetic samples to further our understanding of this area, but we currently recognize the northern geographic boundary of the flycatcher as described in the Recovery Plan (Service 2002, Figures 3, 4).

All willow flycatcher subspecies spend time migrating in the United States from April to June and from July through September. Willow flycatchers, like most small, migratory, insect-eating birds, require food-rich stopover areas

in order to replenish energy reserves and continue their northward or southward migration (Finch

et al.

2000, pp. 71, 78, and 79; Service 2002, pp. E-3, 42). Migration stopover areas are likely critically important for flycatcher productivity and survival (Sogge

et al.

1997, p. 13; Yong and Finch 1997, p. 253; Service 2002, pp. E-3, 19).

Habitat

The flycatcher currently breeds in areas from near sea level to over 2,600 meters (m) (8,500 feet (ft)) (Durst

et al.

2008, p. 14) in vegetation alongside rivers, streams, or other wetlands (riparian habitat). It establishes nesting territories, builds nests, and forages where mosaics of relatively dense and expansive growths of trees and shrubs are established, near or adjacent to surface water or underlain by saturated soil (Sogge

et al.

2010, p. 4). Habitat characteristics such as dominant plant species, size and shape of habitat patch, tree canopy structure, vegetation height, and vegetation density vary widely among breeding sites. Nests are typically placed in trees where the plant growth is most dense, where trees and shrubs have vegetation near ground level, and where there is a low-density canopy. Some of the more common tree and shrub species currently known to comprise nesting habitat include Gooddings willow (

Salix gooddingii

), coyote willow (

Salix exigua

), Geyer's willow (

Salix geyeriana

), arroyo willow (

Salix lasiolepis

), red willow (

Salix laevigata

), yewleaf willow (

Salix taxifolia

), boxelder (

Acer negundo

), tamarisk (also known as saltcedar,

Tamarix ramosissima

), and Russian olive (

Elaeagnus angustifolia

) (Service 2002, p. D-2). While there are exceptions, generally flycatchers are not found nesting in areas without willows, tamarisk, or both.

Use of riparian habitats along major drainages in the Southwest during migration has been documented (Sogge

et al.

1997, pp. 3-4; Yong and Finch 1997, p. 253; Johnson and O'Brien 1998, p. 2; McKernan and Braden 1999, p. 17; Koronkiewicz

et al.

2004, pp. 9-11). Many of the willow flycatchers found migrating are detected in riparian habitats or patches (small areas of riparian vegetation) that would be unsuitable for nest placement (the vegetation structure is too short or sparse, or the patch of vegetation is too small). In these drainages, migrating flycatchers may use a variety of riparian habitats, including ones dominated by native or exotic plant species, or mixtures of both (Service 2002, p. E-3).

Life History

Flycatchers are believed to exist and interact as groups of metapopulations (Service 2002, p. 72). A metapopulation is a group of geographically separate flycatcher breeding populations connected to each other by immigration and emigration (Service 2002, p. 72). Flycatcher populations are most stable where many connected sites or large populations exist (Service 2002, p. 72). Metapopulation persistence or stability is more likely to improve by adding more breeding sites rather than adding more territories to existing sites (Service 2002, p. 72). This would distribute birds across a greater geographical range, minimize risk of simultaneous catastrophic population loss, and avoid genetic isolation (Service 2002, p. 72).

Flycatchers have higher site fidelity (to a local area) than nest fidelity (to a specific nest location) and can move among sites within stream drainages and between drainages (Kenwood and Paxton 2001, pp. 29-31). Within-drainage movements are more common than between-drainage movements (Kenwood and Paxton 2001, p. 18). Juvenile flycatchers were the group of flycatchers that moved (dispersed) the farthest to new and distant breeding sites from the area where they hatched (Paxton

et al.

2007, p. 74). The USGS's 10-year flycatcher study in central Arizona (Paxton

et al.

2007, entire) is the key movement study that has generated these conclusions, augmented by other flycatcher banding and re-sighting studies (Sedgwick 2004, p. 1103; McLeod

et al.

2008, p. 110).

The difference in flycatcher dispersal distance among different study areas and regions reflects the varying spatial arrangement of breeding habitat, illustrating how dispersal tendencies are influenced by the geographic distribution of habitat at the stream segment, drainage, and landscape scales (Paxton

et al.

2007, p. 75). While USGS's study focused its effort in central Arizona at two of the largest breeding sites, it also included multiple auxiliary sites (up to 444 km (275 mi) away), along with other researchers and surveyors across the flycatcher's range paying attention to whether flycatchers were banded or not. As a result, the broad scope of the study of flycatcher movement extends broadly beyond a localized, regional area, where habitat configuration dominates the results.

Banded flycatchers from season to season (and sometimes within season) were recorded moving from 50 m (150 feet) to 444 km (275 mi) to try to nest. Some long-distance season-to-season movement records captured flycatchers moving from the Basin and Mojave Recovery Units to the Lower Colorado Recovery Unit and from the Lower Colorado Recovery Unit to the Gila Recovery Unit.

The USGS assimilated all of the flycatcher movement information and concluded that rapid colonization and increased metapopulation stability could be accomplished by establishing breeding sites within 30 to 40 km (18 to 25 mi) of each other (Paxton

et al.

2007, p. 4). Flycatchers at breeding sites configured in this way would be able to regularly disperse to new breeding sites or move between known breeding sites within the same year or from year-to-year. This proximity of sites would increase the connectivity and stability of the metapopulation and smaller, more distant breeding sites.

Recovery Planning

Because the breeding range of the flycatcher encompasses a broad geographic area with much site variation, the Recovery Plan divides the flycatcher's range into six Recovery Units, each of which are further subdivided into four to seven Management Units (for a total of 32 Management Units) (Service 2002, pp. 61-63). This provides an organizational strategy to “characterize flycatcher populations, structure recovery goals, and facilitate effective recovery actions that should closely parallel the physical, biological, and logistical realities on the ground” (Service 2002, p. 61). Recovery Units are defined based on large watershed and hydrologic units. Within each Recovery Unit, Management Units are based on watershed or major drainage boundaries at the Hydrologic Unit Code Cataloging Unit level (standard watershed boundaries which have already been defined for other purposes). The “outer” boundaries of some Recovery Units and Management Units were defined by the flycatcher's range boundaries. Recovery goals are recommended for 29 of the 32 Management Units, and this designation of critical habitat is organized geographically within these Recovery Units and Management Units (see “Methodology Overview” section below).

The Service's 2002 Recovery Plan provides reasonable actions recommended to recover the flycatcher and provides two criteria, either of which can be met, in order to consider downlisting the species to threatened (Service 2002, pp. 77-78). The first alternative for downlisting requires reaching a total population of 1,500 flycatcher territories geographically distributed among all Recovery Units

and maintained for 3 years with habitat protections (Service 2002, pp. 77-78). Habitat protections include a variety of options such as habitat conservation plans (HCPs), conservation easements, or safe harbor agreements. The second alternative approach for downlisting calls for reaching a population of 1,950 territories also strategically distributed among all Recovery and Management Units for 5 years without additional habitat protection (Service 2002, pp. 77-78).

In order to delist this flycatcher subspecies (to remove it from the List of Endangered and Threatened Wildlife), the Recovery Plan recommends that a minimum of 1,950 territories are geographically distributed among all Recovery and Management Units, and that twice the amount of habitat is provided to maintain these territories over time. Second, these habitats must be protected from threats to assure maintenance of these populations and habitat for the foreseeable future through development and implementation of conservation management agreements (Service 2002, pp. 79-80). Third, all of these delisting criteria must be accomplished and their effectiveness demonstrated for a period of 5 years (Service 2002, pp. 79-80). This critical habitat designation is structured to allow the Service to work toward achieving the numerical, geographical, and habitat-related recovery goals.

Twice the amount of suitable habitat is needed to support the numerical territory goals because the long-term persistence of flycatcher populations cannot be assured by protecting only those habitats in which flycatchers currently breed (Service 2002, p. 80). It is important to recognize that most flycatcher breeding habitats are susceptible to future changes in site hydrology (natural or human-related), human impacts such as development or fire, and natural catastrophic events such as flood or drought (Service 2002, p. 80). Furthermore, as the vegetation at sites matures, it can lose the structural characteristics that make it suitable for breeding flycatchers (Service 2002, p. 80). These and other factors can destroy or degrade breeding sites, such that one cannot expect any given breeding site to remain suitable in perpetuity (Service 2002, p. 80). Thus, it is necessary to have additional suitable habitat available to which flycatchers can readily move if displaced by such habitat loss or change (Service 2002, p. 80).

Summary of Changes From Proposed Rule

In developing the final revised flycatcher critical habitat designation, we reviewed public comments received on the proposed August 15, 2011 (76 FR 50542), revision to critical habitat and the draft economic analysis, draft environmental assessment, and proposed revisions document made available to the public published on July 12, 2012 (77 FR 41147). We also conducted further evaluation of lands proposed as critical habitat; refined our mapping methodologies; and excluded areas from the final designation pursuant to section 4(b)(2) of the Act (16 U.S.C. 1531 et seq.). We are making the following changes to the final rule from the proposed August 15, 2011, revision and subsequent July 12, 2012, document.

Proposed Areas Removed From Final Designation

(1) We excluded a number of river segments and reservoir bottoms under section 4(b)(2) of the Act that we identified as being considered for exclusion in the proposed rule (see Exclusions section below). In this final rule, we did not exclude every area that was identified in the proposed rule as being considered for exclusion. For a complete discussion and analysis of areas excluded and an explanation of the basis for exclusion see the Exclusions section. This is the primary source of reduction in the total designated critical habitat area compared to what we identified in the proposal.

(2) In California, based on information received from public comments, we reviewed maps and reports and reevaluated Little Tujunga Creek in the Santa Clara Management Unit. We discovered that the 2.2-km (1.4-mi) segment of the Little Tujunga Creek is not essential for the flycatcher because it provides minimal habitat, metapopulation stability, and prevention against catastrophic loss. As a result, we determined that it was not essential for flycatcher conservation and did not include it in this final revised critical habitat designation.

(3) In California, we reevaluated mapped information and proposed critical habitat along the Santa Ana River within the Prado Basin in the Santa Ana Management Unit (76 FR 50542, August 15, 2011, pp. 50563-50564). We detected, through additional analysis, several groundwater recharge ponds and areas at, or below, the 154-m (505-ft) elevation line that will be subject to regular inundation. These areas total approximately 900.2 ha (2,224.5 ac), and they do not represent areas that currently have or can develop flycatcher habitat. As a result, we determined that these locations were not essential for flycatcher conservation and do not include them in this final revised critical habitat designation.

(4) In Arizona, in response to comments, we reevaluated information through maps, reports, and site-specific knowledge about the proposed segments of the San Francisco River in the San Francisco Management Unit (76 FR 50542, August 15, 2011, p. 50576). This evaluation resulted in determining that a 2.7-km (1.7-mi) segment of the San Francisco River at Luna Lake, Arizona, which we proposed for designation, does not contain the essential physical or biological features of flycatcher habitat, and it does not appear to have the ability to develop into flycatcher nesting habitat. The habitat surrounding Luna Lake is comprised of cattails and meadow grasses, and a narrow section of stream downstream from the lake primarily consists of conifers. As a result, we determined that this portion of the San Francisco River was not essential for flycatcher conservation and do not include it in this final revised critical habitat designation.

(5) In Arizona, in response to comments, we reevaluated approximately 6.8 ha (16.8 ac) of land within the proposed segment along Pinal Creek, representing about 4 percent of the land outside of the Freeport McMoRan (FMC) administered Pinal Creek Management Area. These lands are located primarily at the perimeter of the floodplain and end of the proposed segment. Because of their placement, these lands provide limited value for the flycatcher outside of the conservation area. As a result, we determined that these disconnected portions of the Pinal Creek floodplain were not essential for flycatcher conservation and do not include them in this final revised critical habitat designation.

(6) In Nevada, we reevaluated the 17.3-km (10.8-mi) stream and other bodies of water in Pahranagat Valley (hereinafter referred to as the Pahranagat River in this final rule) proposed in the Pahranagat National Wildlife Refuge (NWR) in the Pahranagat Management Unit (76 FR 50542, August 15, 2011, p. 50570). Based on our reevaluation, we determined that the southern 13.7 km (8.5 mi) of this segment is not essential for flycatcher conservation. The habitat along this segment consists of open water, marsh, wet meadow, alkali flats, and upland salt desert shrub. The water along this segment is standing, is

ephemeral, or has been channelized in ditches. These areas do not currently consist of riparian tree and shrub species and are unlikely to develop the necessary vegetation for flycatcher habitat in the future. As a result, we determined that these locations were not essential for flycatcher conservation and do not include it in this final revised critical habitat designation.

(7) In Nevada, within the Pahranagat Management Unit, we inaccurately described the Key Pittman Wildlife Area as a 6.3-km (3.9-mi) single stream segment along the Pahranagat River (76 FR 50542, August 15, 2011, p. 50570) and also inaccurately described the area we were considering for exclusion, under section 4(b)(2) of the Act, as a single 4.0-km (2.5-mi) segment (76 FR 50542, p. 50583). The Key Pittman Wildlife Area is more accurately described as being comprised of two separate stream segments, one 2.5 km (1.6 mi) long and the other 1.4 km (0.9 mi) long. Between these two portions of the Key Pittman Wildlife Area is a 2.4-km (1.5-mi) segment of private land, which consists of agricultural fields, and limited water and riparian habitat. Therefore, because of the lack of both flycatcher habitat and likelihood of developing flycatcher habitat in the future, this area between the separate portions of the Key Pittman Wildlife Area should not have been identified as an essential area for flycatcher conservation, and we do not include it in our final critical habitat designation. We are excluding the two stream segments on Key Pittman Wildlife Area under section 4(b)(2) of the Act (see Exclusions section).

(8) In Colorado, we reevaluated information about the habitat on the Los Pinos River in the San Juan Management Unit (76 FR 50542, August 15, 2011, p. 50571) through maps, reports, and site visits (Ireland T. 2012, entire). We found that the northern 9.1-km (5.6-mi) portion of the Los Pinos River is at a high elevation, with a steep stream slope, and the vegetation composition is not consistent with flycatcher habitat. The plant species adjacent to this stream are mostly comprised of those not used by nesting flycatchers (such as alders and conifers). Therefore, this segment does not currently consist of the riparian tree and shrub species used by flycatchers, and it is unlikely to develop them in the future. As a result, we determined that this portion of the Los Pinos River was not essential for flycatcher conservation, and do not include it in this final revised critical habitat designation.

(9) In Colorado, there is a collection of checker-boarded parcels of private land interspersed with Southern Ute tribal land along the Los Pinos River within the San Juan Management Unit that, upon further analysis, we do not consider critical habitat because they are not essential for flycatcher conservation. At the perimeter of Southern Ute tribal lands along the Los Pinos River, but outside of tribal jurisdiction, are collectively about 2.7 intermittent river km (1.7 mi) of private lands. Additionally, at the southern end of the Southern Ute Reservation, approximately 1.2 km (0.8 mi) or less of scattered private land parcels occur. Individually, these parcels are at the perimeter of the floodplain, are small in size, and are not contiguous. Collectively, they represent a small fraction of the area we considered for critical habitat along the Los Pinos River. As result of their small size and limited extent of habitat, we do not consider these segments essential to flycatcher conservation and do not include them in this final revised critical habitat designation.

(10) In Colorado, there are five small parcels of BLM land on the Rio Grande in the San Luis Valley Management Unit that were included in the proposed critical habitat. The farthest upstream section is west of Del Norte and is 300 m (980 feet) long. The other four parcels are south of Alamosa NWR near the Conejos and Costilla County border. The boundary of the first parcel does not intersect with the river but is within the lateral extent of proposed critical habitat and constitutes 3.73 ha (9.21 ac). The second parcel is 135 m (443 feet) long. The third parcel is 0.96 km (0.59 mi) long. The boundary of the fourth parcel also does not intersect the river but is within the lateral extent of proposed critical habitat and constitutes 2.77 ha (6.85 ac). Because these five small, scattered, and limited sections of habitat are not essential to flycatcher recovery, we do not include them in this final revised critical habitat designation.

(11) In New Mexico, in response to comments, we reevaluated information about the Elephant Butte Reservoir portion of the proposed 211.8-km-km (131.6-mi) Rio Grande segment in the Middle Rio Grande Management Unit (76 FR 50542, August 15, 2011). This evaluation resulted in our determination that the downstream 31.4 km (19.5 mi) of the proposed segment within the active conservation pool of Elephant Butte Reservoir is not critical habitat. The 31.4 km (19.5 mi) downstream portion of the proposed segment that is within the active storage pool of Elephant Butte Reservoir is not necessary for the conservation of flycatcher, as the Unit without this portion meets the quantity of habitat and territories identified as essential for this Management Unit (refer to our

Criteria Used To Identify Critical Habitat

section). Therefore, we are not including this portion in the designation for this Management Unit.

More specifically, although the segment contains some elements of the physical or biological features of flycatcher habitat along the reservoir edge, the habitat features in the downstream portion are not essential to flycatcher conservation because the number of flycatcher territories and amount of habitat in the farther upstream portion of this segment have already far exceeded the recovery goals for this Management Unit. The recovery goals in this Management Unit are for 100 flycatcher territories, and the most recent survey data from 2012 found 327 territories in this management unit (USBR 2012, p. 1). Only 33 of these territories occurred in the downstream portion along Elephant Butte Reservoir. Therefore, the upstream portion of the proposed segment within Socorro County has about three times more flycatcher territories than the recovery goals for this management unit. As a result, the lower portion of this segment, where reservoir inundation is more likely, and flycatcher habitat may be less persistent over time, is not needed to reach recovery goals in this management unit. This is consistent with other areas (such as the Roosevelt Management Unit) where we used the numerical and habitat-related recovery goals from the Recovery Plan, along with the current and previous number of known flycatcher territories, to guide the endpoints of critical habitat segments along areas with large populations (see “Methodology Overview,” “Areas with Large Populations”). As a result, we have determined this downstream 31.4 km (19.5 mi) portion of the Rio Grande in Elephant Butte Reservoir does not meet our criteria for, and, therefore, the definition of, critical habitat for the flycatcher, and we have removed it from our final critical habitat designation.

Other Changes

(12) In California, after further analysis of maps and using information received during comments, we have made three revisions to the approximate stream lengths along tribal lands within the San Diego Management Unit. These lands were subsequently excluded from our final designation under section 4(b)(2) of the Act (see Exclusions section).

We incorrectly described the length of the San Diego River occurring along the

Barona Group of Capitan Grande Band of Mission Indians of the Barona Reservation, California and the Viejas (Baron Long) Group of Capitan Grande Mission Indians of the Viejas Reservation, California, as 4.7 km (2.9 mi) (76 FR 50542, August 15, 2011, p. 55082). We have corrected the distance to 0.9 km (0.6 mi) along the San Diego River, consisting of approximately 9.0 ha (22 ac) to accurately reflect tribal ownership of these lands being excluded under section 4(b)(2) of the Act (see Exclusions section).

We incorrectly described the length of the San Luis Rey River occurring along the tribal lands of the Pala Band of Luiseño Mission Indians, California, as 3.7 km (2.3 mi) (76 FR 50542, August 15, 2011, p. 55082). We have corrected the distance to 8.3 km (5.2 mi) along the San Luis Rey River, to accurately reflect tribal ownership of these lands being excluded under section 4(b)(2) of the Act (see Exclusions section).

We incorrectly described the length of the San Luis Rey River occurring along the tribal lands of the Rincon Band of Luiseño Mission Indians, California, as 2.4 km (1.5 mi) (76 FR 50542, August 15, 2011, p. 55082). We have corrected the distance to 4.3 km (2.7 mi) along the San Luis Rey River, to accurately reflect tribal ownership of these lands being excluded under section 4(b)(2) of the Act (see Exclusions section).

(13) In California, we inadvertently did not include the Pala Band of Luiseño Mission Indians' tribal fee lands, currently being brought into trust, for exclusion from the revised critical habitat designation under section (4)(b)(2) of the Act. Subsequently, we received information from them explaining where these fee lands are located, have included them in our exclusion analysis, and are excluding them under section 4(b)(2) of the Act (see Exclusions section).

(14) In California, we inaccurately described the length of a proposed segment of the Santa Ynez River within the Santa Ynez Management Unit within the unit description portion of our proposed rule (76 FR 50542, August 15, 2011, p. 50563). However, we correctly described the end points on the maps within the

Federal Register

notice and maps and electronic maps provided on the Internet and at

http://www.regulations.gov

. The lower Santa Ynez River segment above Vandenberg Air Force Base should more accurately be described as 42.3-km (26.3-mi) segment, not the 27.6-km (17.2-mi) segment described in our proposal.

(15) In California, we inaccurately described the length of a proposed segment of the Santa Ysabel River within the San Diego Management Unit (76 FR 50542, August 15, 2011, p. 50565). The upper San Ysabel River segment that is contiguous with Temescal Creek should more accurately be described as 8.7-km (5.4-mi) segment, not the 9.8-km (6.1-mi) segment described in our proposal.

(16) In California, we inaccurately described the length of a proposed segment of the Cañada Gobernadora Creek within the San Diego Management Unit (76 FR 50542, August 15, 2011, p. 50565). The mapped Cañada Gobernadora Creek segment inadvertently included a portion of San Juan Creek. As a result, the portion of San Juan Creek is not included in this designation, and our Cañada Gobernadora Creek segment is now more accurately a 4.7-km (2.9-mi) segment, not the 5.9-km (3.7-mi) segment described in our proposal.

(17) In Arizona, while we identified San Carlos Apache tribal lands as areas we were considering for exclusion under section 4(b)(2) of the Act, we received new information about parcels of San Carlos Apache tribal lands along the lower San Pedro River between the Aravaipa Creek and Gila River confluence, totaling about 1.0 km (0.6 mi) and 75 ha (185 ha). Subsequently, we have included these separate parcels in our exclusion analysis, and are excluding them under section 4(b)(2) of the Act (see Exclusions section).

(18) In New Mexico, we inaccurately identified and mapped the location of Navajo Nation (Ramah Navajo) as just south of Zuni Pueblo. The most downstream portion of the Zuni River is not on Navajo Nation (Ramah Navajo) lands, but more accurately part of Zuni Pueblo. This portion of the Zuni River on Zuni Pueblo is excluded from this final revised designation of critical habitat under section 4(b)(2) of the Act (see Exclusions section).

(19) In New Mexico, we inaccurately described the length of a proposed segment of the Gila River within the Upper Gila Management Unit (76 FR 50542, August 15, 2011, p. 50574). The Gila River segment from the downstream end of the Middle Gila Box Canyon near the Town of Red Rock downstream across the Arizona State line through the Town of Duncan, Arizona, should more accurately be described as 65.3-km (40.6-mi) segment, not the 62.2-km (38.7-mi) segment described in our proposal.

(20) In Colorado, we included an area within our electronic map of the proposed rule along the Conejos River that was an error. As a result of correcting that error, we are not including an area about 1.6 km (1 mi) in length that was represented as a lateral extent of the Conejos River in this final critical habitat designation. This area included a portion of the Rio Grande National Forest in addition to private land.

(21) While mapping the lateral extent of critical habitat, some side drainages, tributaries, or washes were included within our electronic maps that extend beyond the confluence of the streams we described in the proposal. These areas sometimes extended well beyond the reasonable confluence area, sometimes about 3 km (1.9 mi) up a tributary. For example, portions of San Juan or San Francisquito Creeks in California, or West Clear Creek and Beaver Creek in Arizona, occurred on our electronic maps. We did not describe these segments in the text of the proposed rule, because they were not intended to be part of our proposal. We have truncated these segments to the best of our ability in the final critical habitat maps, so only those habitats on the rivers described are included in the final designation. The removal of these segments resulted in an overall minor reduction in the amount of critical habitat.

(22) While mapping the lengths of stream segments electronically, the results can vary as GIS programs attempt to account for the bends and turns along a stream. Additionally, the irregular shape of properties and the exclusion or revision of segments caused challenges in trying to accurately describe a length of a stream segment. Even when the end points of a segment did not change, as we continued to reassess and recalculate stream lengths and round to the nearest tenth, a change in a few tenths of a kilometer or mile sometimes occurred. Therefore, there is expected to be some minor change in stream lengths between our proposal and this final rule.

(23) Although we attempted to remove as many developed areas as possible (areas that have no conservation value as flycatcher habitat) before publishing the proposed rule, we were not able to eliminate all developed areas. Since publication of the proposed rule and the receipt of more accurate mapping data and information, we were able to further refine the designation, which has resulted in a more precise delineation of habitat containing the physical or biological features necessary to support flycatcher life-history requirements. This resulted in a minor reduction for some segments from the amounts of critical habitat published in the proposed rule. However, it is not possible to remove each and every one of these developed areas even at the

refined mapping scale used; therefore, the maps of the designation may contain areas that do not contain the physical or biological features necessary for the flycatcher. These areas, which include locations such as roads, cement pads, utility substations, agricultural fields, housing, etc., are not critical habitat and are therefore excluded by text in this final rule.

Critical Habitat

Background

Critical habitat is defined in section 3 of the Act as:

(1) The specific areas within the geographical area occupied by the species, at the time it is listed in accordance with the Act, on which are found those physical or biological features:

(a) Essential to the conservation of the species, and

(b) Which may require special management considerations or protection; and

(2) Specific areas outside the geographical area occupied by the species at the time it is listed, upon a determination that such areas are essential for the conservation of the species.

Conservation, as defined under section 3 of the Act, means to use and the use of all methods and procedures that are necessary to bring an endangered or threatened species to the point at which the measures provided pursuant to the Act are no longer necessary. Such methods and procedures include, but are not limited to, all activities associated with scientific resources management such as research, census, law enforcement, habitat acquisition and maintenance, propagation, live trapping, and transplantation, and, in the extraordinary case where population pressures within a given ecosystem cannot be otherwise relieved, may include regulated taking.

Critical habitat receives protection under section 7 of the Act through the requirement that Federal agencies ensure, in consultation with the Service, that any action they authorize, fund, or carry out is not likely to result in the destruction or adverse modification of critical habitat. The designation of critical habitat does not affect land ownership or establish a refuge, wilderness, reserve, preserve, or other conservation area. Such designation does not allow the government or public to access private lands. Such designation does not require implementation of restoration, recovery, or enhancement measures by non-Federal landowners. Where a landowner requests Federal agency funding or authorization for an action that may affect a listed species or critical habitat, the consultation requirements of section 7(a)(2) of the Act would apply, but even in the event of a destruction or adverse modification finding, the obligation of the Federal action agency and the landowner is not to restore or recover the species, but to implement reasonable and prudent alternatives to avoid destruction or adverse modification of critical habitat.

Under the first prong of the Act's definition of critical habitat, areas within the geographical area occupied by the species at the time it was listed are included in a critical habitat designation if they contain physical or biological features (1) which are essential to the conservation of the species and (2) which may require special management considerations or protection. For these areas, critical habitat designations identify, to the extent known using the best scientific and commercial data available, those physical or biological features that are essential to the conservation of the species (such as space, food, cover, and protected habitat). In identifying those physical and biological features within an area, we focus on the principal biological or physical constituent elements (primary constituent elements such as roost sites, nesting grounds, seasonal wetlands, water quality, tide, soil type) that are essential to the conservation of the species. Primary constituent elements are those specific elements of the physical or biological features that provide for a species' life-history processes and are essential to the conservation of the species.

Under the second prong of the Act's definition of critical habitat, we can designate critical habitat in areas outside the geographical area occupied by the species at the time it is listed, upon a determination that such areas are essential for the conservation of the species. For example, an area currently occupied by the species but that was not occupied at the time of listing may be essential to the conservation of the species and may be included in the critical habitat designation. We designate critical habitat in areas outside the geographical area occupied by a species only when a designation limited to its range would be inadequate to ensure the conservation of the species.

Section 4 of the Act requires that we designate critical habitat on the basis of the best scientific and commercial data available. Further, our Policy on Information Standards Under the Act (published in the

Federal Register

on July 1, 1994 (59 FR 34271)), the Information Quality Act (section 515 of the Treasury and General Government Appropriations Act for Fiscal Year 2001 (Pub. L. 106-554; H.R. 5658)), and our associated Information Quality Guidelines, provide criteria, establish procedures, and provide guidance to ensure that our decisions are based on the best scientific data available. They require our biologists, to the extent consistent with the Act and with the use of the best scientific data available, to use primary and original sources of information as the basis for recommendations to designate critical habitat.

When we are determining which areas should be designated as critical habitat, our primary source of information is generally the information developed during the listing process for the species. Additional information sources may include the recovery plan for the species, articles in peer-reviewed journals, conservation plans developed by States and counties, scientific status surveys and studies, biological assessments, other unpublished materials, or experts' opinions or personal knowledge.

Habitat is dynamic, and species may move from one area to another over time. This is particularly true for the flycatcher because its riparian vegetation it uses is prone to alteration and regrowth from periodic disturbance, such as flooding. We recognize that critical habitat designated at a particular point in time may not include all of the habitat areas that we may later determine are necessary for the recovery of the species. For these reasons, a critical habitat designation does not signal that habitat outside the designated area is unimportant or may not be needed for recovery of the species. Areas that are important to the conservation of the species, both inside and outside the critical habitat designation, will continue to be subject to: (1) Conservation actions implemented under section 7(a)(1) of the Act; (2) regulatory protections afforded by the requirement in section 7(a)(2) of the Act for Federal agencies to insure their actions are not likely to jeopardize the continued existence of any endangered or threatened species; and (3) section 9 of the Act's prohibitions on taking any individual of the species, including taking caused by actions that affect habitat. Federally funded or permitted projects affecting listed species outside their designated critical habitat areas may still result in jeopardy findings in some cases. These protections and conservation tools will

continue to contribute to recovery of this species. Similarly, critical habitat designations made on the basis of the best available information at the time of designation will not control the direction and substance of future recovery plans, HCPs, or other species conservation planning efforts if new information available at the time of these planning efforts calls for a different outcome.

Physical or Biological Features

In accordance with section 3(5)(A)(i) and 4(b)(1)(A) of the Act and regulations at 50 CFR 424.12, in determining which areas within the geographical area occupied by the species at the time of listing to designate as critical habitat, we consider the physical or biological features essential to the conservation of the species and which may require special management considerations or protection. These include, but are not limited to:

(1) Space for individual and population growth and for normal behavior;

(2) Food, water, air, light, minerals, or other nutritional or physiological requirements;

(3) Cover or shelter;

(4) Sites for breeding, reproduction, or rearing (or development) of offspring; and

(5) Habitats that are protected from disturbance or are representative of the historical, geographical, and ecological distributions of a species.

We derive the specific physical or biological features essential for the flycatcher from studies of this species' habitat, ecology, and life history as described below. Additional information can be found in the final listing rule published in the

Federal Register

on February 27, 1995 (60 FR 10694), and the Flycatcher Recovery Plan (Service 2002, entire), Survey Protocol and Natural History Summary (Sogge

et al.

2010, entire), and the 10-year central Arizona ecology study (Paxton

et al.

2007, entire).

In general, the areas designated as critical habitat are designed to provide sufficient riparian habitat for breeding, non-breeding, territorial, dispersing, and migrating flycatchers in order to reach the geographic distribution, abundance, and habitat-related recovery goals described in the Recovery Plan (Service 2002, pp. 77-85). We are not designating any areas as critical habitat solely because they serve as a migration habitat. Instead, the areas we are designating serve a variety of functions, including habitat to be used by migrating flycatchers. The habitat components important for conservation of this subspecies were determined from studies of flycatcher behavior and habitat use throughout the bird's range (see Background section).

In general, the physical or biological features of critical habitat for nesting flycatchers are found in the riparian areas within the 100-year floodplain or flood-prone area. Flycatchers use riparian habitat for feeding, sheltering, and cover while breeding, migrating, and dispersing. It is important to recognize that flycatcher habitat is ephemeral in its presence, and its distribution is dynamic in nature because riparian vegetation is prone to periodic disturbance (such as

flooding) (Service 2002, p. 17). Even with the dynamic shifts in habitat conditions, one or more of the primary constituent elements described below are found throughout each of the units that we are designating as critical habitat.

Flycatcher habitat may become unsuitable for breeding through maturation or disturbance of the riparian vegetation, but it may remain suitable for use during migration or for foraging. This situation may be only temporary, and vegetation may cycle back into suitability as breeding habitat (Service 2002, p. 17). Therefore, it is not practical to assume that any given breeding habitat area will remain suitable over the long term or persist in the same location (Service 2002, p. 17). Over a 5-year period, flycatcher habitat can, in optimum conditions, germinate, be used for migration or foraging, continue to grow, and eventually be used for nesting. Thus, flycatcher habitat that is not currently suitable for nesting at a specific time, but is useful for foraging and migration, can still be important for flycatcher conservation. Feeding sites and migration stopover areas are important components for the flycatcher's survival, productivity, and health, and they can also be areas where new breeding habitat develops as nesting sites are lost or degraded (Service 2002, p. 42). These successional cycles of habitat change are important for long-term persistence of flycatcher habitat.

Based on our current knowledge of the life history and ecology of the flycatcher and the relationship of its life-history functions to its habitat, as summarized in the Background section above and in more detail in the Recovery Plan (Service 2002, Chapter II), it is important to recognize the interconnected nature of the physical or biological features that provide the primary constituent elements of critical habitat. Specifically, we consider the relationships between river function, hydrology, floodplains, aquifers, and plant growth, which form the environment essential to flycatcher conservation.

The hydrologic regime (stream flow pattern) and supply of (and interaction between) surface and subsurface water is a driving factor in the long-term maintenance, growth, recycling, and regeneration of flycatcher habitat (Service 2002, p. 16). As streams reach the lowlands, their gradients typically flatten and surrounding terrain opens into broader floodplains (Service 2002, p. 32). In these geographic settings, the stream-flow patterns (frequency, magnitude, duration, and timing) will provide the necessary stream-channel conditions (wide configuration, high sediment deposition, periodic inundation, recharged aquifers, lateral channel movement, and elevated groundwater tables throughout the floodplain) that result in the development of flycatcher habitat (Poff

et al.

1997, pp. 770-772; Service 2002, p. 16). Allowing the river to flow over the width of the floodplain, when overbank flooding occurs, is integral to allow deposition of fine moist soils, water, nutrients, and seeds that provide the essential material for plant germination and growth. An abundance and distribution of fine sediments extending farther laterally across the floodplain and deeper underneath the surface retains much more subsurface water, which in turn supplies water for the development of the vegetation that provides flycatcher habitat and micro-habitat conditions (Service 2002, p. 16). The interconnected interaction between groundwater and surface water contributes to the quality of riparian vegetation community (structure and plant species) and will influence the germination, density, vigor, composition, and the ability of vegetation to regenerate and maintain itself (Arizona Department of Water Resources 1994, pp. 31-32).

In many instances, flycatcher breeding sites occur along streams where human impacts are minimized enough to allow more natural processes to create, recycle, and maintain flycatcher habitat. However, there are also breeding sites that are supported by various types of supplemental water including agricultural and urban run-off, treated water outflow, irrigation or diversion ditches, reservoirs, and dam outflows (Service 2002, p. D-15). Although the waters provided to these habitats might be considered “artificial,” they are often important for maintaining the habitat in appropriate condition for breeding flycatchers within the existing environment.

In considering the specific physical or biological features essential for flycatcher conservation, it is also important to consider longer-term processes that may influence habitat changes over time, such as climate change. Climate change is a long-term shift in the statistics of the weather (including its averages). In its

Fourth Assessment Report,

the Intergovernmental Panel on Climate Change (IPCC) defines climate change as, “a change in the state of the climate that can be identified by changes in the mean and/or variability of its properties and that persists for an extended period, typically decades or longer” (Solomon

et al.

2007, p. 943). Changes in climate already are occurring. Examples of observed changes in the physical environment include an increase in global average sea level and declines in mountain glaciers and average snow cover in both the northern and southern hemispheres (IPCC 2007a, p. 30). At continental, regional, and ocean basin scales, observed changes in long-term trends of other aspects of climate include: a substantial increase in precipitation in eastern parts of North American and South America, northern Europe, and northern and central Asia; declines in precipitation in the Mediterranean, southern Africa, and parts of southern Asia; and an increase in intense tropical cyclone activity in the North Atlantic since about 1970 (IPCC 2007a, p. 30).

Projections of climate change globally and for broad regions through the 21st century are based on the results of modeling efforts using state-of-the-art Atmosphere-Ocean General Circulation Models and various greenhouse gas emissions scenarios (Meehl

et al.

2007, p. 753; Randall

et al.

2007, pp. 596-599). As is the case with all models, there is uncertainty associated with projections due to assumptions used and other features of the models. However, despite differences in assumptions and other parameters used in climate change models, the overall surface air temperature trajectory is one of increased warming in comparison to current conditions (Meehl

et al.

2007, p. 762; Prinn

et al.

2011, p. 527). Among the IPCC's projections for the 21st century are the following: (1) It is virtually certain there will be warmer and more frequent hot days and nights over most of the earth's land areas; (2) it is very likely there will be increased frequency of warm spells and heat waves over most land areas, and the frequency of heavy precipitation events will increase over most areas; and (3) it is likely that increases will occur in the incidence of extreme high sea level (excludes tsunamis), intense tropical cyclone activity, and the area affected by droughts in various regions of the world (IPCC 2007b, p. 8).

Changes in climate can have a variety of direct and indirect ecological impacts on species, and can exacerbate the effects of other threats. Climate-associated environmental changes to the landscape, such as decreased stream flows, increased water temperatures, reduced snowpack, and increased fire frequency, affect species and their habitats. The vulnerability of a species to climate change impacts is a function of the species' sensitivity to those changes, its exposure to those changes, and its capacity to adapt to those changes. The best available science is used to evaluate the species' response to these stressors. We recognize that future climate change may present a particular challenge evaluating habitat conditions for species like the flycatcher because the additional stressors may push species beyond their ability to survive in their present location.

Exactly how climate change will affect precipitation in the specific areas with flycatcher habitat is uncertain. However, consistent with recent observations of regional effects of climate change, the projections presented for the Southwest predict warmer, drier, and more drought-like conditions (Hoerling and Eischeid 2007, p. 19; Seager

et al.

2007, p. 1181). For example, climate simulations of the Palmer Drought Severity Index (a calculation of the cumulative effects of precipitation and temperature on surface moisture balance) for the Southwest for the periods of 2006 to 2030 and 2035 to 2060 show an increase in drought severity with surface warming. Additionally, drought still increases even during wetter simulations because of the effect of heat-related moisture loss through evaporation and evapotranspiration (Hoerling and Eischeid 2007, p. 19). Annual mean precipitation is likely to decrease in the Southwest, as is the length of snow season and snow depth (IPCC 2007b, p. 887). Most models project a widespread decrease in snow depth in the Rocky Mountains and earlier snowmelt (IPCC 2007b, p. 891). In summary, we expect that climate change will result in a warmer, drier climate, and reduced surface water across the flycatcher's range.

In the recent past, drought has had both negative and positive effects on breeding flycatchers and their habitat, which can provide insight into how climate change may affect flycatchers and flycatcher habitat. For example, the extreme drought of 2002 caused near complete reproductive failure of the 146 flycatcher territories at Roosevelt Lake in central Arizona (Smith

et al.

2003, pp. 8, 10), and caused a dramatic rise in the prevalence of non-breeding and unpaired flycatchers (Paxton

et al.

2007, p. 4). While extreme drought during a single year can generate impacts to breeding success, drought can also have localized short-term benefits in some regulated environments. For instance, at some reservoirs (such as Roosevelt Lake, Arizona, and Lake Isabella, California), drought led to reduced water storage, which increased the exposure of wet soils at the lake's perimeter. Continued drought in those areas allowed the exposed areas to grow vegetation and become new flycatcher nesting habitat (Ellis

et al.

2008, p. 44). These short-term and localized habitat increases are not likely sustainable with persistent drought or long-term predictions of a drier environment, because of the overall importance of the presence of surface water and elevated groundwater needed to grow dense riparian forests for flycatcher habitat. As a result, we expect long-term climate trends associated with a drier climate to have an overall negative effect on the available rangewide habitat for flycatchers.

Considering these issues and other information regarding the biology and ecology of the species, we have determined that the flycatcher requires the essential physical or biological features described below.

Space for Individual and Population Growth and for Normal Behavior

Streams of lower gradient and more open valleys with a wide and broad floodplain are the geological settings that are known to support flycatcher breeding habitat from near sea level to about 2,600 m (8,500 ft) in elevation in southern California, southern Nevada, southern Utah, southern Colorado, Arizona, and New Mexico (Service 2002, p. 7). Lands with moist conditions that support riparian plant communities are areas that provide flycatcher habitat. Conditions like these typically develop in lower elevation floodplains as well as where streams enter impoundments, either natural (such as beaver ponds) or human-made (reservoirs). Low-gradient stream conditions may also occur at high elevations, as in the marshy mountain meadows supporting flycatchers in the headwaters of the Little Colorado River near Greer, Arizona, or the flat-gradient portions of the upper Rio Grande in south-central Colorado and northern New Mexico (Service 2002, p. 32). Sometimes, the

low-gradient wider floodplain exists only at the habitat patch itself within a stream that is otherwise steeper in gradient (Service 2002, p. D-12).

Relatively steep, confined streams can also support flycatcher breeding habitat (Service 2002, p. D-13). For instance, a portion of the San Luis Rey River in California supports a substantial flycatcher population and stands out among flycatcher habitats as having a relatively high gradient and being confined in a fairly narrow, steep-sided valley (Service 2002, p. D-13). Even a steep, confined canyon or mountain stream may present local conditions where just a small area less than a hectare (acre) in size of flycatcher breeding habitat may develop (Service 2002, p. D-13). Such sites are important individually and in aggregate to contribute to metapopulation stability, site connectivity, and gene flow (Service 2002, p. D-13). Flycatchers can occupy very small, isolated habitat patches and may occur in fairly high densities within those small patches.

Many willow flycatchers are found along streams using riparian habitat during migration (Yong and Finch 1997, p. 253; Service 2002, p. E-3). Migration stopover areas can be similar to breeding habitat or riparian habitats with less vegetation density and abundance compared to areas for nest placement (the vegetation structure is too short or sparse or the patch is too small) (Service 2002, p. E-3). For example, many locations where migrant flycatchers were detected on the lower Colorado River (LCR) (Koronkiewicz

et al.

2004, pp. 9-11) and throughout Arizona in 2004 (Munzer

et al.

2005, Appendix C) were areas surveyed for territories, but none were detected. Such migration stopover areas, even though not used for breeding, are critically important resources affecting productivity and survival (Service 2002, p. E-3). The variety of riparian habitat occupied by migrant flycatchers ranges from small patches with shorter and sparser vegetation to larger more complex breeding habitats.

Therefore, based on the information above, we identify streams of lower gradient and more open valleys with a wide or broad floodplain an essential physical or biological feature of flycatcher habitat. In some instances, streams in relatively steep, confined areas can also support flycatcher breeding habitat (Service 2002, p. D-13). These areas support the abundance of riparian vegetation used for flycatcher nesting, foraging, dispersal, and migration.

Food, Water, Air, Light, Minerals, or Other Nutritional or Physiological Requirements

Food

The flycatcher is somewhat of an insect generalist (Service 2002, p. 26), taking a wide range of invertebrate prey including flying, and ground- and vegetation-dwelling species of terrestrial and aquatic origins (Drost

et al.

2003, pp. 96-102). Wasps and bees (Hymenoptera) are common food items, as are flies (Diptera), beetles (Coleoptera), butterflies, moths and caterpillars (Lepidoptera), and spittlebugs (Homoptera) (Beal 1912, pp. 60-63; McCabe 1991, pp. 119-120). Plant foods such as small fruits have also been reported (Beal 1912, pp. 60-63; Roberts 1932, p. 20; Imhof 1962, p. 268), but are not a significant food during the breeding season (McCabe 1991, pp. 119-120). Diet studies of adult flycatchers (Drost

et al.

1998, p.1; DeLay

et al.

1999, p. 216) found a wide range of prey taken. Major prey items were small (flying ants) (Hymenoptera) to large (dragonflies) (Odonata) flying insects, with Diptera and Hemiptera (true bugs) comprising half of the prey items. Willow flycatchers also took non-flying species, particularly Lepidoptera larvae. From an analysis of the flycatcher diet along the South Fork of the Kern River, California (Drost

et al.

2003, p. 98), flycatchers consumed a variety of prey from 12 different insect groups. Flycatchers have been identified targeting seasonal hatchings of aquatic insects along the Salt River arm of Roosevelt Lake, Arizona (Paxton

et al.

2007, p. 75).

Flycatcher food availability may be largely influenced by the density and species of vegetation, proximity to and presence of water, saturated soil levels, and microclimate features such as temperature and humidity (Service 2002, pp. 18, D-12). Flycatchers forage within and above the tree canopy, along the patch edge, in openings within the territory, over water, and from tall trees as well as herbaceous ground cover (Bent 1960, pp. 209-210; McCabe 1991, p. 124). Flycatchers employ a “sit and wait” foraging tactic, with foraging bouts interspersed with longer periods of perching (Prescott and Middleton 1988, p. 25).

Therefore, based on the information above, we identify the presence of a wide range of invertebrate prey, including flying and ground- and vegetation-dwelling species of terrestrial and aquatic origins to be an essential physical or biological feature of flycatcher habitat.

Water

Flycatcher nesting habitat is largely associated with perennial (persistent) stream flow that can support the expanse of vegetation characteristics needed by breeding flycatchers, but there are exceptions. Flycatcher nesting habitat can persist on intermittent (ephemeral) streams that retain local conditions favorable to riparian vegetation (Service 2002, p. D-12). The range and variety of stream flow conditions (frequency, magnitude, duration, and timing) (Poff

et al.

1997, pp. 770-772) that will establish and maintain flycatcher habitat can arise in different types of both regulated and unregulated flow regimes throughout its range (Service 2002, p. D-12). Also, flow conditions that will establish and maintain flycatcher habitat can be achieved in regulated streams, depending on scale of operation and the interaction of the primary physical characteristics of the landscape (Service 2002, p. D-12).

In the Southwest, hydrological conditions at a flycatcher breeding site can vary remarkably within a season and between years (Service 2002, p. D-12). At some locations, particularly during drier years, water or saturated soil is only present early in the breeding season (May and part of June) (Service 2002, p. D-12). At other sites, vegetation may be immersed in standing water during a wet year but be hundreds of meters from surface water in dry years (Service 2002, p. D-12). This is particularly true of reservoir sites such as the Kern River at Lake Isabella, California; Roosevelt Lake, Arizona; and Elephant Butte Reservoir, New Mexico (Service 2002, p. D-12). Similarly, where a river channel has changed naturally, there may be a total absence of water or visibly saturated soil for several years. In such cases, the riparian vegetation and any flycatchers breeding within it may persist for several years (Service 2002, p. D-12).

In some areas, natural or managed hydrologic cycles can create temporary flycatcher habitat, but may not be able to support it for an extended amount of time, or may support varying amounts of habitat at different points in the cycle. Some dam operations create varied situations that allow different plant species to thrive when water is released below a dam, held in a lake, or removed from a lakebed, and consequently, varying degrees of flycatcher habitat are available as a result of dam operations (Service 2002, p. 33). The riparian vegetation that constitutes flycatcher breeding habitat requires substantial water (Service 2002,

p. D-12). Because flycatcher breeding habitat is often where there is slow-moving or still water, these slow and still water conditions may also be important in influencing the production of insect prey base for flycatcher food (Service 2002, p. D-12). These slow-moving water situations can also be managed or mimicked through manipulated supplemental water originating from sources such as agricultural return flows or irrigation canals (Service 2002, p. D-15).

Therefore, based on the information above, we identify flowing streams with a wide range of stream flow conditions that support expansive riparian vegetation as an essential physical feature of flycatcher habitat. The most common stream flow conditions are largely perennial (persistent) stream flow with a natural hydrologic regime (frequency, magnitude, duration, and timing). However, in the Southwest, hydrological conditions can vary, causing some flows to be intermittent, but the floodplain can retain surface moisture conditions favorable to expansive and flourishing riparian vegetation. These appropriate conditions can be supported by managed water sources and hydrological cycles that mimic key components of the natural hydrologic cycle.

Sites for Germination or Seed Dispersal

Subsurface hydrologic conditions may in some places (particularly at the more arid locations of the Southwest) be equally important to surface water conditions in determining riparian vegetation patterns (Lichivar and Wakely 2004, p. 92). Where groundwater levels are elevated to the point that riparian forest plants can directly access those waters, it can be an area for breeding, non-breeding, territorial, dispersing, foraging, and migrating flycatchers. Elevated groundwater helps create moist soil conditions believed to be important for nesting conditions and prey populations (Service 2002, pp. 11, 18), as further discussed below.

Depth to groundwater plays an important part in the distribution of riparian vegetation (Arizona Department of Water Resources 1994, p. 31) and, consequently, flycatcher habitat. The greater the depth to groundwater below the land surface, the less abundant the riparian vegetation (Arizona Department of Water Resources 1994, p. 31). Localized, perched aquifers (a saturated area that sits above the main water table) can and do support some riparian habitat, but these systems are not extensive (Arizona Department of Water Resources 1994, p. 31).

The abundance and distribution of fine sediment deposited on floodplains is critical for the development, abundance, distribution, maintenance, and germination of the plants that grow into flycatcher habitat (Service 2002, p. 16). Fine sediments provide seed beds to facilitate the growth of riparian vegetation for flycatcher habitat. In almost all cases, moist or saturated soil is present at or near breeding sites during wet and non-drought years (Service 2002, p. 11). The saturated soil and adjacent surface water may be present early in the breeding season, but only damp soil is present by late June or early July (Service 2002, p. D-3). Microclimate features (temperature and humidity) facilitated by moist or saturated soil, are believed to play an important role where flycatchers are detected and nest, their breeding success, and availability and abundance of food resources (Service 2002, pp. 18, D-12).

Therefore, based on the information above, we identify elevated subsurface groundwater taZbles and appropriate floodplain fine sediments as essential physical or biological features of flycatcher habitat. These features provide water and seedbeds for the germination, growth, and maintenance of expansive growth of riparian vegetation needed by the flycatcher.

Cover or Shelter

Riparian vegetation (described more in detail within the “Sites for Breeding, Reproduction, or Rearing (or Development) of Offspring” section) also provides the flycatcher cover and shelter while migrating and nesting. Placing nests in dense vegetation provides cover and shelter from predators or nest parasites that would seek out flycatcher adults, nestlings, or eggs. Similarly, using riparian vegetation for cover and shelter during migration provides food-rich stopover areas, a place to rest, and shelter or cover along migratory flights (Service 2002, pp. D-14, F-16). Riparian vegetation used by migrating flycatchers can sometimes be less dense and abundant than areas used for nesting (Service 2002, p. D-19). However, migration stopover areas, even though not used for breeding, may be critically important resources affecting local and regional flycatcher productivity and survival (Service 2002, p. D-19).

Therefore, based on the information above, we identify riparian tree and shrub species (described in more detail below) that provide cover and shelter for nesting, breeding, foraging, dispersing, and migrating flycatchers as essential physical or biological features of flycatcher habitat.

Sites for Breeding, Reproduction, or Rearing (or Development) of Offspring

Reproduction and Rearing of Offspring

Riparian habitat characteristics such as dominant plant species, size and shape of habitat patches, tree canopy structure, vegetation height, and vegetation density are important parameters of flycatcher breeding habitat, although they may vary widely at different sites (Service 2002, p. D-1). The accumulating knowledge of flycatcher breeding sites reveals important areas of similarity, which constitute the basic concept of what is suitable breeding habitat (Service 2002, p. D-2). These habitat features are generally discussed below.

Flycatchers nest in thickets of trees and shrubs ranging in height from 2 m to 30 m (6 to 98 ft) (Service 2002, p. D-3). Lower-stature thickets (2-4 m or 6-13 ft tall) tend to be found at higher elevation sites, with tall-stature habitats at middle- and lower-elevation riparian forests (Service 2002, p. D-2). Nest sites typically have dense foliage at least from the ground level up to approximately 4 m (13 ft) above ground, although dense foliage may exist only at the shrub level, or as a low, dense tree canopy (Service 2002, p. D-3).

Regardless of the plant species' composition or height, breeding sites usually consist of dense vegetation in the patch interior, or an aggregate of dense patches interspersed with openings creating a mosaic that is not uniformly dense (Service 2002, p. 11). Common tree and shrub species currently known to comprise nesting habitat include Gooddings willow, coyote willow, Geyer's willow, arroyo willow, red willow, yewleaf willow, pacific willow (

Salix lasiandra

), boxelder, tamarisk, and Russian olive (Service 2002, pp. D-2, D-11). Other plant species used for nesting have been buttonbush (

Cephalanthus occidentalis

), cottonwood, stinging nettle (

Urtica dioica

), alder (

Alnus rhombifolia, Alnus oblongifolia, Alnus tenuifolia

), velvet ash (

Fraxinus velutina

), poison hemlock (

Conium maculatum

), blackberry (

Rubus ursinus

), seep willow (

Baccharis salicifolia, Baccharis glutinosa

), oak (

Quercus agrifolia, Quercus chrysolepis

), rose (

Rosa californica, Rosa arizonica, Rosa multiflora

), sycamore (

Platanus wrightii

), giant reed (

Arundo donax

), false indigo (

Amorpha californica

), Pacific poison ivy (

Toxicodendron diversilobum

), grape

(

Vitis arizonica

), Virginia creeper (

Parthenocissus quinquefolia

), Siberian elm (

Ulmus pumila

), and walnut (

Juglans hindsii

) (Service 2002, pp. D-3, D-5, D-9). Other species used by nesting flycatchers may become known over time as more studies and surveys occur.

Canopy density (the amount of cover provided by tree and shrub branches measured from the ground) at various nest sites ranged from 50 to 100 percent (Service 2002, p. D-3). Flycatcher breeding habitat can be generally organized into three broad habitat types—those dominated by native vegetation (typically willow), by exotic (nonnative) vegetation (typically salt cedar), and those with mixed native and those dominated by exotic plants (typically salt cedar and willow).

These broad habitat descriptors reflect the fact that flycatchers inhabit riparian habitats dominated by both native and nonnative plant species. Salt cedar and Russian olive are two exotic plant species used by flycatchers for nest placement and also foraging and shelter (Service 2002, p. D-4). The riparian patches used by breeding flycatchers vary in size and shape (Service 2002, p. D-2). They may be relatively dense, linear, contiguous stands or irregularly-shaped mosaics of dense vegetation with open areas (Service 2002, pp. D-2-D-11).

Flycatchers use tamarisk (or salt cedar) and Russian olive for nest placement, foraging, roosting, cover, migration, and dispersal. Fewer than half (44 percent) of the known flycatcher territories occur in habitat patches that are greater than 90 percent native vegetation in composition (Durst

et al.

2008, p.15). About 50 percent of all known flycatcher territories are located at breeding sites that include mixtures of native and exotic plant species (mostly tamarisk) (Durst

et al.

2008, p.15). In many of these areas, exotic plant species are significant contributors to the habitat structure by providing the dense lower strata vegetation that flycatchers prefer (Durst

et al.

2008, p.15). A USGS comparative study (Sogge

et al.

2005, p. 1) found no difference in flycatcher physiology, immunology, site fidelity, productivity, or survivorship between flycatchers nesting in tamarisk-dominated habitat versus native-dominated habitats. Tamarisk habitats vary with respect to suitability for breeding flycatchers across their range, just as do native habitats (Sogge

et al.

2005, p.1). While the literature refutes or questions the negative environmental impacts of tamarisk (Glenn and Nagler 2005, pp. 1-2; USGS 2010, pp. vi-xviii), many riparian vegetation improvement projects focus on the eradication or control of tamarisk. The implementation of these projects requires careful evaluation (see Special Management Considerations or Protections below) and success can rely on the improvement of the physical or biological features included in this determination associated with river flow and groundwater (Service 2002, Appendices H and K).

Flycatchers have been recorded nesting in patches as small as 0.1 ha (0.25 ac) along the Rio Grande, and as large as 70 ha (175 ac) in the upper Gila River, New Mexico (Service 2002, p. 17). The mean reported size of flycatcher breeding patches was 8.6 ha (21.2 ac), with the majority of sites toward the smaller end, as evidenced by a median patch size of 1.8 ha (4.4 ac) (Service 2002, p. 17). Mean patch size of breeding sites supporting 10 or more flycatcher territories was 24.9 ha (62.2 ac). Aggregations of occupied breeding patches within a breeding site may create a riparian mosaic as large as 200 ha (494 ac), such as areas like the Kern River (Whitfield 2002, p. 2), Alamo Lake, Roosevelt Lake (Paradzick

et al.

1999, pp. 6-7), and Lake Mead (McKernan 1997, p. 13).

Flycatchers can cluster their territories into small portions of riparian sites (Whitfield and Enos 1996, p. 2; Sogge

et al.

1997, p. 24), and major portions of the site may only be used briefly or not at all in any given year. Habitat modeling based on remote sensing and electronic Geographic Information System (GIS) data has found that breeding site occupancy at reservoir sites in Arizona is influenced by vegetation characteristics of habitat adjacent to the actual nesting areas (Hatten and Paradzick 2003, pp. 774, 782); therefore, areas adjacent to nest sites can be an important component of a breeding site. How size and shape of riparian patches relate to factors such as flycatcher nest-site selection and fidelity, reproductive success, predation, and brood parasitism is unknown (Service 2002, p. D-11).

With only some exceptions, flycatchers are generally not found nesting in confined floodplains (typically those bound within a narrow canyon) (Hatten and Paradzick 2003, p. 780) or where only a single narrow strip of riparian vegetation less than approximately 10 m (33 ft) wide develops (Service 2002, p. D-11). While riparian vegetation too mature, too immature, or of lesser quality in abundance and breadth may not be used for nesting, it can be used by breeding flycatchers for foraging (especially if it extends out from larger patches) or during migration for foraging, cover, and shelter (Sogge and Tibbitts 1994, p. 16; Sogge and Marshall 2000, p. 53).

Therefore, based on the information above, we identify a variety of riparian tree and shrub species as essential physical or biological features of flycatcher habitat. Typically, dense expansive riparian forests provide habitat to place nests. Riparian vegetation of broader quality, with a mosaic of open spaces, typically surround locations to place nests or along river segments and provide vegetation for foraging, perching, dispersal, and migration, and habitat that can develop into nesting areas through time.

Primary Constituent Elements for Flycatcher

Under the Act and its implementing regulations, we are required to identify the physical or biological features essential to flycatcher conservation in areas occupied at the time of listing, focusing on the features' primary constituent elements. Primary constituent elements are those specific elements of the physical or biological features that provide for a species' life-history processes and are essential to the conservation of the species.

Based on our current knowledge of the physical or biological features and habitat characteristics required to sustain the species' life-history processes, we determine that the primary constituent elements specific to the flycatcher are:

(1) Primary Constituent Element 1—

Riparian vegetation.

Riparian habitat along a dynamic river or lakeside, in a natural or manmade successional environment (for nesting, foraging, migration, dispersal, and shelter) that is comprised of trees and shrubs (that can include Gooddings willow, coyote willow, Geyer's willow, arroyo willow, red willow, yewleaf willow, pacific willow, boxelder, tamarisk, Russian olive, buttonbush, cottonwood, stinging nettle, alder, velvet ash, poison hemlock, blackberry, seep willow, oak, rose, sycamore, false indigo, Pacific poison ivy, grape, Virginia creeper, Siberian elm, and walnut) and some combination of:

(a) Dense riparian vegetation with thickets of trees and shrubs that can range in height from about 2 to 30 m (about 6 to 98 ft). Lower-stature thickets (2 to 4 m or 6 to 13 ft tall) are found at higher elevation riparian forests and tall-stature thickets are found at middle- and lower-elevation riparian forests;

(b) Areas of dense riparian foliage at least from the ground level up to

approximately 4 m (13 ft) above ground or dense foliage only at the shrub or tree level as a low, dense canopy;

(c) Sites for nesting that contain a dense (about 50 percent to 100 percent) tree or shrub (or both) canopy (the amount of cover provided by tree and shrub branches measured from the ground);

(d) Dense patches of riparian forests that are interspersed with small openings of open water or marsh or areas with shorter and sparser vegetation that creates a variety of habitat that is not uniformly dense. Patch size may be as small as 0.1 ha (0.25 ac) or as large as 70 ha (175 ac).

(2) Primary Constituent Element 2—

Insect prey populations.

A variety of insect prey populations found within or adjacent to riparian floodplains or moist environments, which can include: flying ants, wasps, and bees (Hymenoptera); dragonflies (Odonata); flies (Diptera); true bugs (Hemiptera); beetles (Coleoptera); butterflies, moths, and caterpillars (Lepidoptera); and spittlebugs (Homoptera).

With this critical habitat designation, we intend to identify the physical or biological features essential to the conservation of the species, through the identification of the features' primary constituent elements sufficient to support the life-history processes of the species.

Physical or Biological Features and Primary Constituent Elements Summary

The discussion above outlines those physical or biological features essential to flycatcher conservation and presents our rationale as to why those features were selected. The primary constituent elements described above are results of the dynamic river or lakeside environment that germinates, develops, maintains, and regenerates the riparian forest and provides food for breeding, non-breeding, dispersing, territorial, and migrating flycatchers.

Anthropogenic factors such as dams, irrigation ditches, or agricultural field return flow can assist in providing or mimicking the conditions that support flycatcher habitat. In regulated environments, riparian vegetation improvement projects associated with planting, irrigation, and cultivation may also require manual manipulation to maintain suitability over the long term.

Because the flycatcher exists in disjunct breeding populations across a wide geographic and elevation range and its habitat is subject to dynamic events (such as flooding and drying), the quantity and spatial arrangement of critical habitat river segments described below are essential for the flycatcher to maintain metapopulation stability, connectivity, and gene flow, and to protect against catastrophic loss. All river segments designated as flycatcher critical habitat are either: (1) Within the known range of the subspecies, representing areas known to be occupied at the time of listing; or (2) essential areas for the conservation of the species not known to be occupied by the flycatcher at the time of listing, but now may or may not be known to have flycatchers present. These areas contain at least one the primary constituent elements of the physical or biological features essential for the conservation of the subspecies. It is important to recognize that the primary constituent elements such as riparian vegetation with trees and shrubs of a certain type and insect prey populations are present throughout the river segments selected, but the specific quality of riparian habitat for nesting (which involve elements such as specific configuration of riparian foliage, sites for nesting, and interspersion of small openings), migration, foraging, and shelter will not remain constant in condition or location over time due to succession (plant germination and growth) and the dynamic environment in which they exist.

In order to reach the goal of conserving the subspecies by recovering an adequate geographical distribution that represents ecological diversity of the flycatcher populations, the distribution and abundance of flycatcher habitat and breeding populations must improve across the 29 Management Units (see Background section). The recovery goal is 1,950 flycatcher territories geographically and numerically distributed in the appropriate Management Units along with twice the habitat needed to maintain these territories (see Background section). Also, these areas must hold these populations for a number of years and be protected through conservation agreements or other means. The most recent rangewide flycatcher assessment estimated that there were about 1,300 flycatcher territories (Durst

et al.

2008, p. 13). The Lower Colorado, Upper Colorado, and Basin and Range Recovery Units need the most growth in known territories and habitat to reach recovery goals. While there is still great variance in the known number of territories within the Coastal California, Gila, and Rio Grande Recovery Units, these areas are closer in number of territories and amount of habitat to the established recovery goals. The numeric territory goals established per Management Unit are in denominations of 25. The goal for some Management Units may be as few as 25 territories or as many as 325.

With this designation of critical habitat, we intend to identify the physical or biological features essential to the conservation of the species, through the identification of the features' primary constituent elements sufficient to support the life-history processes of the species.

Special Management Considerations or Protections

When designating critical habitat, we assess whether the specific areas within the geographical area occupied by the species at the time of listing contain features that are essential to the conservation of the species and which may require special management considerations or protection.

As mentioned briefly or referenced in this rule, the flycatcher and its habitat are threatened by a multitude of factors occurring at once. Threats to those features that define critical habitat (elements of physical or biological features) are caused by various factors. We believe the essential features within the critical habitat areas will require some level of management or protection (or both) to address the current and future threats and maintain the quality, quantity, and arrangement of the elements of physical or biological features essential to flycatcher conservation.

Essential features in need of special management occur not only at the immediate locations where the flycatcher may be present, but at additional areas needed to reach recovery goals and areas that can provide for normal population fluctuations and habitat succession that may occur in response to natural and unpredictable events. The flycatcher may be dependent upon habitat components beyond the immediate areas where individuals of the species occur if they are important in maintaining ecological processes such as hydrologic regimes; plant germination, growth, maintenance, and regeneration (succession); sedimentation; groundwater elevations; plant health and vigor; or maintenance of prey populations.

The designation of critical habitat does not imply that lands outside of critical habitat do not play an important role in flycatcher conservation. Federal activities outside of critical habitat are still subject to review under section 7 of the Act if they may affect the flycatcher or its critical habitat (such as groundwater pumping, developments, watershed condition). Prohibitions of

section 9 of the Act also continue to apply both inside and outside of designated critical habitat.

A detailed discussion of threats to the flycatcher and its habitat can be found in the final listing rule (60 FR 10694, February 27, 1995), the previous critical habitat designations (62 FR 39129, July 22, 1997; 70 FR 60886, October 19, 2005), and the final Recovery Plan (Service 2002, pp. 33-42, Appendix F). Some of the special management actions that may be needed for essential features of flycatcher habitat are briefly summarized below.

(1) Restore adequate water-related elements to improve and expand the quality, quantity, and distribution of riparian habitat. Special management may: increase efficiency of groundwater management; use urban water outfall and irrigation delivery and tail waters for vegetation improvement; maintain, improve, provide, or reestablish instream flows to expand the quality, distribution, and abundance of riparian vegetation; increase the width between levees to expand the active channel during overbank flooding; and manage regulated river flows to more closely resemble the natural hydrologic regime.

(2) Retain riparian vegetation in the floodplain. Special management may include the following actions: avoid clearing channels for flood flow conveyance or plowing of flood plains; and implement projects to minimize clearing of vegetation (including exotic vegetation) to help ensure that desired native species and exotic vegetation persist until an effective riparian vegetation improvement plan can be implemented.

(3) Manage biotic elements and processes. Special management may include the following actions: manage livestock grazing to increase flycatcher habitat quality and quantity by determining appropriate areas, seasons, and use consistent within the natural historical norm and tolerances; reconfigure grazing units, improve fencing, and improve monitoring and documentation of grazing practices; manage wild and feral hoofed-mammals (ungulates) (e.g., elk, horses, burros) to increase flycatcher habitat quality and quantity; and manage keystone species such as beaver to restore desired processes to increase habitat quality and quantity.

(4) Protect riparian areas from recreational impacts. Special management may include actions such as managing trails, campsites, off-road vehicles, and fires to prevent habitat development and degradation in flycatcher habitat.

(5) Manage exotic plant species, such as tamarisk or Russian olive, by reducing conditions that allow exotics to be successful, and restoring or reestablishing conditions that allow native plants to thrive. Throughout the range of the flycatcher, the success of exotic plants within river floodplains is largely a symptom of land and water management (for example, groundwater withdrawal, surface water diversion, dam operation, and unmanaged grazing) that has created conditions favorable to exotic plants over native plants. Special management may include the following actions: eliminate or reduce dewatering stressors such as surface water diversion and groundwater pumping to increase stream flow and groundwater elevations; reduce salinity levels by modifying agricultural practices and restoring natural hydrologic regimes and flushing flood flows; in regulated streams, restore more natural hydrologic regimes that favor germination and growth of native plant species. Improve timing of water draw down in lake bottoms to coincide with the seed dispersal and germination of native species; and restore ungulate herbivory to intensities and levels under which native riparian species are more competitive.

(6) Manage fire to maintain and enhance habitat quality and quantity. Special management may include the following actions: suppress fires that occur; and reduce risk of fire by restoring elevated groundwater levels, base flows, flooding, and natural hydrologic regimes in order to prevent drying of riparian areas and more flammable exotic plant species from developing; and reduce risk of recreational fires.

(7) Evaluate and conduct exotic plant species removal and native plant species management on a site-by-site basis. If habitat assessments reveal a sustained increase in exotic plant abundance, conduct an evaluation of the underlying causes and conduct vegetation improvement under measures described in the Recovery Plan (Service 2002, Appendices H and K). Remove exotics only if: underlying causes for dominance have been addressed; there is evidence that exotic species will be replaced by vegetation of higher functional value; and the action is part of an overall vegetation improvement plan. Native riparian vegetation improvement plans should include: a staggered approach to create mosaics of different aged successional tree and shrub stands; consideration of whether the sites are presently occupied by nesting flycatchers; and management of stressors that can improve the germination, growth, and maintenance of preferred vegetation.

(8) Manage or reduce the occurrence, spread, and effects of biocontrol agents on flycatcher habitat. Exotic biocontrol tamarisk leaf beetle insects (leaf beetles) were brought into and released in many locations throughout the western United States. This specific U.S. Department of Agriculture program was terminated in 2010, largely because these insects are moving farther and thriving in the southwestern United States (within the flycatcher's breeding range) where it was initially believed they would not persist (APHIS 2010, p. 2). However, leaf beetles still exist within the United States, and specifically within the northern range of the flycatcher in Nevada, Arizona, and New Mexico. It is unknown to what extent these leaf beetles will continue to move throughout the Southwest. Their overall impact or benefit to the flycatcher, flycatcher habitat, and other wildlife species is also unknown, but there are predictions that the beetles could occur throughout the western United States and into northern Mexico (Tracy

et al.

2008, pp. 1-3). There is concern about effects to the flycatcher in places throughout much of its range where the landscape does not support healthy native riparian vegetation (even in the absence of tamarisk). Along the Virgin River in southwestern Utah, flycatcher breeding attempts have failed concurrent with leaf beetle impacts to the vegetation (Paxton

et al.

2010, p.1). Rangewide, tamarisk is a habitat component of over half of all known flycatcher territories (Durst

et al.

2007, p. 15). Therefore, it would be beneficial to prevent purposeful or accidental intra- or interstate transport of leaf beetles to locations that would increase the likelihood of beetles dispersing to flycatcher habitat. Similarly, because insects can travel or be moved large distances, prevent the additional release of leaf beetles (in all their varieties) into the environment where they can eventually occur within flycatcher habitat. Where leaf beetle-related impacts may occur or are happening, consider the previous items in this list and the Recovery Plan for strategies to help improve the germination and growth of native plants (Service 2002, p. Appendix K).

Criteria Used To Identify Critical Habitat

As required by section 4(b)(1)(A) of the Act, we use the best scientific and commercial data available to designate critical habitat. We review available information pertaining to the habitat requirements of the species (or in this

instance, a willow flycatcher subspecies). In accordance with the Act and its implementing regulation at 50 CFR 424.12(e), we consider whether designating additional areas—outside those currently occupied as well as those occupied at the time of listing—are necessary to ensure the conservation of this flycatcher subspecies.

As defined under section 3(5)(A)(i) of the Act, we are designating critical habitat in areas within the geographical area known to be occupied by nesting flycatchers at the time of listing in 1995 that contain the essential physical or biological features and require special management or protections. As defined under section 3(5)(A)(ii) of the Act, we also are designating specific areas outside the geographical area occupied by nesting flycatchers at the time of listing (but that are within its known historical breeding distribution), because such areas are essential for the conservation of the species as supported by the geographical and numerical flycatcher territory and habitat-related recovery goals established in the Recovery Plan (Service 2002, pp. 84-85).

Stream Segments as Critical Habitat

We are designating “stream segments” as the descriptor for the designated area of flycatcher critical habitat (which in some areas also includes exposed reservoir bottoms). Stream segments are appropriate for delineating critical habitat because in addition to providing stream-side vegetation for flycatchers to place nests, stream segments satisfy other various flycatcher life needs adjacent to or between nesting sites (foraging habitat, streams, elevated groundwater tables, moist soils, flying insects, and other alluvial floodplain habitats) (see

Physical or Biological Features

section). Also, the dynamic processes of riparian vegetation succession (loss and regrowth) and river hydrology allow for stream segments to provide both current and future areas for flycatcher habitat to grow. Riparian vegetation in these segments is expected to naturally expand and contract from flooding, inundation, drought, and the resulting changes in the extent and location of floodplains and river channels (Service 2002, pp. 18, D-13-D-15). Therefore, while one or more of the physical or biological features are currently present, over time these habitat features will fluctuate in quality or location throughout these stream segments. Management of stream flows and other anthropogenic (manmade) factors, such as agricultural practices or dam operations, can also influence the location and quality of the riparian vegetation in many of these stream segments. The lateral extent of each river segment occurs within the 100-year floodplain (see

Physical or Biological Features

section) and is further described below (see Lateral Extent section). Therefore, designating stream segments as critical habitat will provide for the variety of flycatcher uses and allow for ever-changing streamside vegetation habitat quality (in location and abundance).

Occupancy at the Time of Listing

We identified areas occupied at the time of listing in 1995 as those streams where flycatcher territories were detected in any one season from surveys conducted from 1991 to 1994 (Sogge and Durst 2008). The flycatcher rangewide database (Sogge and Durst 2008) is the authoritative source for determining territories because our 1995 flycatcher listing rule did not list all known data regarding flycatcher distribution and abundance. We considered a broader area to be occupied than just the specific site where a territory was located because flycatchers are a neotropical migrant traveling between Central America (and possibly northern South America) and the United States using migration stopover areas for food, cover, and shelter, and they are known to move to different nest areas from year to year.

Because flycatchers are neotropical migrants that occupy riparian areas along rivers while traveling between wintering and breeding grounds, we expect that abundant small areas along long stretches of stream can be irregularly occupied by migrant flycatchers from year-to-year. North- and south-bound migrating flycatchers are frequently found occupying stopover areas along streams upstream of, downstream of, and between known breeding sites (Yong and Finch 1997, pp. 265-266; Service 2002, pp. E2-E3; Koronkiewicz

et al.

2004, pp. 9-11). In Arizona, migrant flycatchers were detected at 204 sites statewide along 15 of 19 river drainages surveyed for nesting flycatchers over a 10-year period (Ellis

et al.

2008, p. 26). Over 600 migrant willow flycatchers (subspecies not known) were detected along the length of the LCR in 2004 (Ellis

et al.

2008, p. 26), where only a relatively few known breeding sites and territories exist.

Similarly, flycatchers are known to have fidelity to a larger area along stream drainages (rather than specific nest site fidelity), and can move their territory locations about 30 to 40 km (18 to 25 mi) from year to year (Paxton

et al.

2007, p. 4). Locations with breeding habitat that are within 30 to 40 km (18 to 25 mi) of each other will have higher metapopulation connectivity, and there is a higher probability of colonization of new habitats that are within this distance (Paxton

et al.

2007, p. 76). Sometimes, flycatchers can even move to a very distant location, dispersing as far as 444 km (275 mi) from a previous year's nesting area (Paxton

et al.

2007, p. 2). These year-to-year movements are facilitated by the dynamic nature of flycatcher habitat, changing in quality and location over time. More dramatic changes in habitat quality caused by events such as flooding or inundation can force flycatchers to move their breeding location, thus causing them to use broader locations and habitat quality.

Therefore, for this wide-ranging bird, it is difficult to precisely determine known occupied areas due to the following considerations: (1) The flycatcher's neotropical migratory habits of occupying stopover areas along streams upstream of, downstream of, and between breeding sites; and (2) the season-to-season variation in habitat quality and subsequent lack of specific nest-site fidelity. As a result, for the purpose of this critical habitat designation, we believe it is most conservative and reasonable to conclude that any stream segment along a stream where flycatcher territories were detected from 1991 to 1994 also be considered occupied at the time of listing. Those stream segments considered occupied at the time of listing and those considered not occupied at the time of listing that we are designating as revised critical habitat are organized by Recovery and Management Units (see below) and described briefly in the unit descriptions below. All of the stream segments occupied at the time of listing contain one or more of the primary constituent elements supported by the physical or biological features, which may require special management considerations, or protection as described above. We also include whether flycatcher territories were detected on stream segments not known to be occupied at the time of listing (but are essential for flycatcher conservation).

Recovery Plan Guidance

We relied heavily on the Recovery Plan (Service 2002) to help identify the areas that we are designating as revised critical habitat because the Recovery Plan represents a compilation of the best scientific data available to us. We particularly used the information from the Recovery Plan, such as distribution and abundance of flycatchers, flycatcher

natural history and habitat needs, and stream segments with substantial recovery value, to help identify stream segments with features essential to flycatcher conservation.

The Recovery Plan's strategy, rationale, and science for conservation of the flycatcher guided our efforts to identify essential features (elements in sufficient quantity and spatial arrangement) and areas of critical habitat (Service 2002, pp. 61-95). Because of the wide distribution of this bird and the dynamic nature of its habitat, it was important to designate critical habitat in areas throughout all of the breeding range of the flycatcher that have stated recovery goals. This widespread distribution of habitat is intended to allow flycatchers to function as a group of metapopulations, realize gene flow throughout its range, provide ecological connectivity among disjunct populations, allow for breeding site colonization potential, and prevent catastrophic population losses.

The Recovery Plan (Service 2002, pp. 74-76) identifies important factors to consider in minimizing the likelihood of extinction. These factors were also considered in our approach to designating areas for critical habitat: (1) The territory is the appropriate unit of measure for numerical flycatcher recovery goals; (2) populations should be distributed throughout the bird's range; (3) populations should be distributed close enough to each other to allow for movement among them; (4) large populations contribute most to metapopulation stability, while smaller populations can contribute to metapopulation stability when arrayed in a matrix with high connectivity; (5) as the population of a site increases, the potential to disperse and colonize increases; (6) increase and decrease in one population affects other populations; (7) some Recovery and Management Units have stable metapopulations, but others do not; (8) maintaining or augmenting (or both) existing populations is a greater priority than establishing new populations; and (9) establishing habitat close to existing breeding sites increases the chance of colonization.

Methodology Overview

Our goal was to propose stream segments as critical habitat within 29 of the 32 Management Units (which are geographic areas clustered within 6 Recovery Units) in order to meet the specific numerical flycatcher territory and habitat-related recovery goals (Service 2002, pp. 84-85), which are the same criteria that we are using to identify physical or biological features and designate areas that are essential to flycatcher conservation. Three of the 32 Management Units (Lower Gila, Pecos, and Texas) do not have any goals identified in the Recovery Plan because of either the lack of habitat, the inability for habitat to recover, or the determination that meaningful populations could not be established and persist. Therefore, no critical habitat was proposed or designated within these three Management Units. Numerical flycatcher territory recovery goals for each of the 29 Management Unit vary throughout the flycatcher's range from as few as 25 territories to as many as 325 (Service 2002, pp. 84-85).

In relying on these recovery goals and strategies, we used a methodology with two basic strategies to identify areas and, subsequently, river segments within those areas to propose and consider as critical habitat. First, we identified areas based upon the presence of large breeding populations and areas with multiple small breeding populations that when found in proximity, form a large population. Once these areas were established, we identified the specific end points of the stream segments of flycatcher habitat. Second, for those Management Units with a specific number of territories required to meet recovery goals, but no, or very few, known flycatcher territories, we used information from the Recovery Plan (Service 2002, pp. 86-92) and other relevant sources to identify river segments with flycatcher habitat. The results of this strategy were the identification of streams that: (1) Were within the geographical area known to be occupied by flycatchers at the time of listing with elements of the physical or biological features; (2) the identification of essential areas that were not known to be occupied by flycatchers at the time of listing but that also include elements of the physical or biological features of critical habitat; and (3) the identification of areas for critical habitat that have never been known to be occupied by flycatchers but are essential for the conservation of the flycatcher in order to meet recovery goals.

Areas With Large Populations

To identify the areas with flycatcher habitat in each Management Unit, we first considered specific areas that are known since 1991 to have had large populations of nesting flycatchers. Since the time of listing in 1995, the known distribution and abundance of flycatcher territories has increased primarily due to increased survey effort (Durst

et al.

2008, p. 4). Population increases have also been detected at specific areas where habitat quality and quantity improved. As a result of more extensive surveys and research, and in particular re-establishing known occupancy of breeding sites in Nevada, Utah, and Colorado, the extent of streams known to be used by migrating, non-breeding, and dispersing flycatchers has also expanded. Following the most recent rangewide estimate in 2007, 1,299 territories were described occurring in California, Nevada, Utah, Colorado, Arizona, and New Mexico (Durst

et al.

2008, p. 4). Additional sites have been detected in the following years, but an updated rangewide estimate has not yet been compiled.

The locations of breeding sites were generated from standardized flycatcher surveys conducted from 1991 to 2010. There has been a standardized survey protocol since the 1995 listing of the flycatcher that biologists have used to confirm the presence of flycatcher territories that has produced reliable and accurate information (Tibbitts

et al.

1994, p. 1; Sogge

et al.

1997, p. 1; Sogge

et al.

2010, p. 1). To help ensure the protocol is being used properly, the Service and our partners provide annual training on protocol implementation and flycatcher status, identification, and natural history.

A variety of sources were used to determine breeding site location and information from 1991 to 2010. The Recovery Plan (Service 2002), the USGS flycatcher rangewide database (Sogge and Durst 2008), the 2007 flycatcher rangewide report (Durst

et al.

2008), and recent survey information for the 2008, 2009, and 2010 breeding seasons were all used as authoritative sources of information on breeding flycatcher distribution and abundance. The flycatcher rangewide database developed and maintained by USGS (Sogge and Durst 2008) compiles the results of surveys conducted throughout the bird's range since 1991. The most recent rangewide assessment of flycatcher distribution and abundance analyzed by USGS (Durst

et al.

2008) estimates the number of territories that occur following the 2007 breeding season, taking into account that the entire range of the flycatcher is not surveyed completely in any single year. A summary of known historical breeding records can be found in the Recovery Plan (Service 2002, pp. 8-10). We also evaluated data in reports submitted during section 7 consultations and by biologists holding section 10(a)(1)(A) recovery permits; research published in peer-reviewed articles, agency reports, and databases;

and regional GIS coverages and habitat models.

We also examined 2008 to 2010 data that the Service in Arizona, Nevada, Utah, and Colorado compiled and entered into separate databases and spreadsheets and data from the USGS and U.S. Bureau of Reclamation (USBR) for California and New Mexico, respectively. These data were compatible and therefore able to be added to results of the 2007 USGS rangewide database (Sogge and Durst 2008) and report (Durst

et al.

2008, entire) to identify breeding site locations, territory abundance and distribution, and large populations. However, these additional 3 years of raw data have not been synthesized by USGS into their overall USGS rangewide database (Sogge and Durst 2008) and analyzed (consistent with Durst

et al.

2008, entire) to estimate the overall existing number of territories across the flycatcher's range in a single year. Since this newer information has not be analyzed along with the remainder of the data, the data up to 2007 were the best available information for us to identify the overall number of estimated territories known to occur across a geographic area, such as a Management Unit or Recovery Unit. Therefore, the best available information for estimating the number of territories rangewide is the compiled information up through the 2007 breeding season (Durst

et al.

2008, entire; Sogge and Durst 2008).

In order to identify areas with large flycatcher populations, we first considered and defined a “large” population. We defined a large population as a single breeding site or collection of smaller connected breeding sites that support 10 or more territories in a single year. We selected 10 or more territories to identify a large population because the flycatcher population viability analysis indicates a breeding site exhibits greatest long-term stability with at least 10 territories (Service 2002, p. 72). Large populations persist longer than small ones, and produce more dispersers capable of emigrating to other populations or colonizing new areas (Service 2002, p. 74). In addition, smaller populations with high connectivity to other small populations can provide as much or more stability than a single isolated larger population with the same number of territories because of the potential to disperse colonizers throughout the network of breeding sites (Service 2002, p. 75).

Once the distribution and abundance of flycatcher breeding sites were identified and mapped, we considered the degree of connectivity to assign smaller separate flycatcher breeding sites and the distance from large populations to evaluate these areas as critical habitat. In other words, how much area around breeding sites should be considered as critical habitat? To determine these distances, we examined the known between-year movements of banded adult and juvenile flycatchers. The USGS's 10-year flycatcher study in central Arizona is the key movement study that has generated these conclusions (Paxton

et al.

2007, pp. 59-80), augmented by other flycatcher banding and re-sighting studies (Sedgwick 2004, p. 1103; McLeod

et al.

2008, pp. 93-112). These studies found that flycatchers have higher site fidelity than nest fidelity and can move among breeding sites within drainages and between drainages (Kenwood and Paxton 2001, pp. 30-31). Within-drainage movements are more common than between-drainage movements (Paxton

et al.

2007, p. 77). Juveniles disperse the farthest and were the only group of flycatchers to connect very distant populations (Paxton

et al.

2007, p. 74). Banded flycatchers from season-to-season were recorded moving across a wide area from 50 m (150 feet) to 444 km (275 mi) (Paxton

et al.

2007, p. 2).

Because of the broad range of flycatcher movements, it is a challenge to apply a single distance to characterize the degree of connectivity of separated flycatcher breeding sites. However, USGS (Paxton

et al.

2007, pp. 4, 76, 84, 139, 140) assimilated all of the movement information and concluded that rapid colonization of flycatcher breeding sites and increased metapopulation stability could be accomplished by establishing breeding sites within 30 to 40 km (18 to 25 mi) of each other. Flycatchers at these breeding sites can disperse or move between sites within the same year or from year-to-year. This proximity of these sites would increase the connectivity and stability of the metapopulation and smaller, more distant breeding sites.

As a result of USGS's conclusion, we decided to use 35 km (22 mi), the average of the reported range, as a radius to identify an area surrounding known large flycatcher breeding sites and the distance to connect smaller populations to identify a large population. Because there was no distinction by USGS of a distance within this 30 to 40 km (18 to 25 mi) range that was more valuable to flycatchers, we believe the average is the best representation. After a large population area was established, we determined whether other breeding sites in proximity occurred. If so, this would add to our large population area, generate an additional 35-km (22-mi) radius and extend our area, and so on. We also used this 35-km (22-mi) radius to identify those highly connected breeding sites with a small number of territories that together equaled a large flycatcher population.

Following the identification of these areas that surround large flycatcher populations, we determined where flycatcher habitat occurred on streams and where to establish end points for critical habitat. We used the Recovery Plan and other literature sources and local knowledge to identify stream segments. In combination with these areas of flycatcher habitat, we then considered the numerical and habitat-related recovery goals, and current and previous number of known territories. We also considered site-specific knowledge of these streams, aerial photography, agency reports, and input from other resource managers. The proximity and connectivity of segments to known populations and metapopulation stability were also key aspects of the flycatcher's natural history we considered in delineating river segment end points.

In both the Roosevelt and Middle Rio Grande Management Units, our methods identified a large population area where the current number of flycatcher territories needed to reach management unit recovery goals has been surpassed by two and three times, respectively. In order to identify stream segments and end points for critical habitat that supports our recovery goals in this unique situation, we considered additional factors such as the known fluctuation and persistence of territories over time (such as those associated with reservoir inundation), territory proximity, and metapopulation stability. Both Management Units have large flycatcher populations located within the conservation space of reservoirs, which can produce a large amount of habitat and number of territories. But the persistence of these reservoir habitats and territories can also be lessened as a result of precipitation, river inflow, and dam operations that affect habitat availability over time. Therefore, because of the dynamic fluctuation of habitat and territories within these reservoirs, we selected areas of habitat that overall can contain a greater number of territories than are identified in the Recovery Plan in order to meet the goals for habitat and territory persistence over time. These habitats included portions of reservoirs and streamside habitat outside of these reservoirs, which together, can support the goals of territory and habitat

persistence through time when lake elevations remain high. With the number of current territories far exceeding recovery goals in these Management Units, we found that some occupied habitats at the perimeter of our large population areas became less important to reach recovery goals. Because of the unique situation where the number of territories exceeds the numerical goals established in the Recovery Plan, we did not identify some portions of stream segments with territories along the Rio Grande and Salt River as critical habitat. Although these areas were occupied at the time of listing and had some of the elements of physical and biological features, they were determined not to be essential for flycatcher conservation and were not included as critical habitat.

Nearly the entire areas of the San Diego and Santa Ana Management Units in the Coastal California Recovery Unit were identified as a large population area because of the wide distribution and proximity of occupied streams segments within them. In contrast to other Management Units, our methods were unable to distinguish more specific areas to designate within these Management Units.

Also, our methodology discussed above was unable to distinguish areas within some Management Units where neither large populations nor small populations with high connectivity were known to occur. For example, in the Amargosa, Santa Cruz, San Francisco, Hassayampa and Agua Fria, San Juan, Powell, and Lower Rio Grande Management Units, there are no known breeding sites with 10 or more flycatcher territories, nor are any known territories in high connectivity that create a large population. Similarly, in some Management Units a large population and surrounding area was identified, but that area was found not to be of adequate size to include enough river segments needed to support the number of territories called for in the recovery goals. This situation occurred in the Little Colorado, Santa Ynez, and Santa Clara Management Units. In all of these cases, we used the guidance from the Recovery Plan, local knowledge about habitat, and other information available to identify additional stream segments as important to meet recovery goals, and therefore, essential for the conservation of flycatcher.

When generating the river segments in the situations where there were few territories to help guide us, we relied heavily upon recommendations and strategies provided in the Recovery Plan and local knowledge of habitat conditions, maps, and flycatcher natural history. We also sought information from other sources through this critical habitat designation process. The Recovery Plan identified portions of streams for each Management Unit that would contribute significantly toward recovery (Service 2002, pp. 86-92). These streams were not listed for the purpose of designating critical habitat nor were they intended to be the only streams that were important for recovery, but they did identify streams of substantial recovery value. Also, we have generated additional information since the Recovery Plan was completed about river segments and whether they have or do not have substantial recovery value. Still, the list of stream segments described in the Recovery Plan (Service 2002, pp. 86-92) provides important guidance, especially for Management Units where there are few known flycatcher sites, to guide our critical habitat designation. Site-specific knowledge of these streams, aerial photography, agency reports, and input from other resource managers were also considered. The proximity and connectivity of segments to known populations and metapopulation stability were also key aspects of the flycatcher's natural history we considered in delineating these areas.

The streams designated as revised flycatcher critical habitat are described below. Those streams not within the geographical area known to be occupied at the time of listing were determined to be essential for flycatcher conservation.

Migratory Habitat

Habitat for migrating flycatchers is captured in this revised designation by our approach to identify critical habitat as “river segments” and distributing segments across the flycatcher's breeding range within the southwestern United States. We are currently unable to distinguish the value of specific locations along particular streams for flycatcher migration, because stopover areas contain broad habitat quality in wide-ranging locations, are only for short-term use, and have uncertain occurrence from year-to-year (Finch

et al.

2000, pp. 73, 76-77). Additionally, flycatchers are difficult to distinguish from other flycatcher species and subspecies during migration (Finch

et al.

2000, pp. 71-72). Migrant flycatchers can sometimes be found in unusual locations away from riparian areas (Finch

et al.

2000, p. 76), but many, if not most, are detected while searching for nesting flycatchers (McLeod

et al.

2005, pp. 9-11; Ellis

et al.

2008, pp. 26-27). An extensive study of flycatcher habitat use along the LCR (from Lake Mead to Mexico) and some of its major tributaries in Arizona and southern Nevada and Utah found migrating flycatchers in consecutive years occurring in nearly all study areas and over half of the survey sites (McLeod

et al.

2005, pp. 9-11; Koronkiewicz

et al.

2006, pp. 11-13). Similarly, migratory flycatcher movement was regularly detected along the Middle Rio Grande (Yong and Finch 1997, p. 255). As a result of these factors, we expect similar flycatcher migration behavior for the other major drainages where flycatchers breed throughout its range and where these locations are included within this designation. Therefore, flycatcher migration habitat is captured within our methods for identifying critical habitat to reach recovery goals, because: (1) We are designating areas as broader river segments; (2) our areas will be geographically located across a broad area of the Southwest encompassing most of the range of the flycatcher; and (3) we are identifying areas surrounding territory and breeding sites where migrant flycatchers are most often detected.

Lateral Extent

For the lateral extent or width of flycatcher critical habitat, we considered the variety of purposes riparian habitat serves the flycatcher; the dynamic nature of rivers and riparian habitat; the relationship between the location of rivers, flooding, and riparian habitat; and the expected boundaries, over time, of these habitats. The condition or quality of riparian habitat that flycatchers use adjacent to streams for breeding, feeding, sheltering, cover, dispersal, and migration stopover areas varies. Riparian habitat is dependent on the location of river channels, floodplain soils, subsurface water, and floodplain shape, and is driven by the wide variety of high, medium, and low flow events. In addition, manmade factors such as diversion ditches or agricultural return flows can also influence riparian vegetation distribution. Over time, river channels can braid or move from one side of the floodplain to the other. Flooding occurs at periodic frequencies that recharge aquifers and that deposit and moisten fine floodplain soils which create seedbeds for riparian vegetation germination and growth within these boundaries.

In this designation, we consider the riparian zone where flycatcher habitat occurs to be the area surrounding the select river segment that is directly influenced by river functions. The present boundaries, for mapping purposes, of the lateral extent or riparian zone (in other words, the

surrogate for the delineation of the lateral boundaries of critical habitat within stream segments) were derived by one of two methods. The area was either captured from existing digital data sources (listed below) or created through expert visual interpretation of remotely sensed data (aerial photographs and satellite imagery—also listed below). GIS technology was utilized throughout the lateral extent determination. ESRI, Inc. ArcInfo 8.3 was used to perform all mapping functions and image interpretation. Pre-existing data sources used to assist in the process of delineating the lateral extent of the riparian zones for this designation included: (1) National Wetlands Inventory digital data from the mid-1980s, 2001, and 2002; (2) Federal Emergency Management Agency 1995, Q3 100 year flood data; (3) U.S. Census Bureau Topologically Integrated Geographic Encoding and Referencing (TIGER); and (4) 2000 digital data. The riparian zone is anticipated to occur within the 100-year floodplain.

Where pre-existing data may not have been available to readily define riparian zones, visual interpretation of remotely sensed data was used to define the lateral extent. Data sources used in this included: (1) Terraserver online Digital Orthophoto Quarter Quads, black and white, 1990s era and 2001; (2) USGS Digital Orthophoto Quarter Quads 1997; (3) USGS aerial photographs, 1 meter, color-balanced, and true color, 2002; (4) Landsat 5 and Landsat 7 Thematic Mapper, bands 4, 2, 3, 1990-2000; (5) Emerge Corp, 1 meter, true color imagery, 2001; (6) Local Agency Partnership, 2 foot, true color, 2000; and (7) NWI aerial photographs, 2001-2002.

We refined all lateral extents for this designation by creating electronic maps of the lateral extent and attributing them according to the following riparian sub-classifications. Riparian developed areas, as defined below, are not included in our critical habitat designation since these areas do not contain the primary constituent elements (see

Primary Constituent Elements for the Flycatcher

section above), are not considered essential to flycatcher conservation and, therefore, do not meet the definition of critical habitat. We separated riparian areas into the following two categories: (1) Riparian Vegetated: This class is used to describe areas still in natural unvegetated wetlands, water bodies, and any undeveloped or unmanaged lands within the approximate riparian zone. (2) Riparian Developed: This class is used to describe all developed areas, such as urban and suburban development, agriculture, utility structures and stations, mining, and extraction.

Mapping

When determining critical habitat boundaries within this final rule, we made every effort to avoid including developed areas such as lands covered by buildings, pavement, and other structures because such lands lack physical or biological features for the flycatcher. These types of developments are not often found adjacent to rivers within floodplains, and may not be found on recent maps. The scale of the maps we prepared under the parameters for publication within the Code of Federal Regulations may not reflect the removal of such developed lands. Any such developed lands inadvertently left inside critical habitat boundaries shown on the maps of this final rule have been excluded by text in the rule and are not designated as critical habitat. Therefore, a Federal action involving these developed lands will not trigger section 7 consultation with respect to critical habitat and the requirement of no adverse modification unless the specific action would affect the physical or biological features in the adjacent critical habitat.

The critical habitat designation is defined by the map or maps, as modified by any accompanying regulatory text, presented at the end of this document in the rule portion. We include more detailed information on the boundaries of the critical habitat designation in the preamble of this document. We will make the coordinates or plot points or both on which each map is based available to the public on

http://www.regulations.gov

at Docket No. FWS-R2-ES-2011-0053 on our Internet site at

http://www.fws.gov/southwest/es/arizona/

, and at the field office responsible for the designation (see

FOR FURTHER INFORMATION CONTACT

above).

Summary of Criteria Used To Identify Critical Habitat

Our initial steps and approach in generating areas for flycatcher critical habitat were to identify areas: (1) Known to be within the specific geographic area occupied by the flycatcher at the time of listing (from surveys occurring from 1991 to 1994) that contain the physical or biological features which may require special management or protections; and (2) that are essential to flycatcher conservation based on the Recovery Plan goals.

Following the evaluation of the two factors above, our goal was to incorporate the conservation strategies described in the Recovery Plan. These strategies describe the importance of flycatcher habitat to support stable and growing breeding populations, to provide migration stopover areas, to protect against simultaneous catastrophic loss, to maintain gene flow, to prevent isolation and extirpation, and to provide colonizers to use new areas. Also, the Recovery Plan describes the importance of habitat that supports large breeding populations of flycatchers and small populations that, when in proximity, equal a large population. To achieve these goals, the Recovery Plan describes a recovery strategy of distributing flycatcher habitat that could hold a specific minimum number of breeding territories across 29 different Management Units in portions of California, Nevada, Utah, Colorado, Arizona, and New Mexico.

We therefore created criteria and methodology to identify areas surrounding large populations and small populations, in proximity, that equaled a large population. We used a 35-km (22-mi) distance as a radius to identify areas around large flycatcher populations (those with at least 10 territories) and small populations in high connectivity that together equal a large population.

We chose to generate critical habitat in “river segments” to account for the dynamic aspects of flycatcher riparian habitat, the changing locations of flycatcher habitat due to these dynamic conditions, population growth, and the variety of other life-history needs such as nest placement, foraging, dispersing, cover, shelter, and migration habitat. Once these broad areas were established, we identified stream segments with flycatcher habitat that we believe will support the numerical territory and habitat-related recovery goals for the 29 Management Units described in the Recovery Plan.

Some Management Units with recovery goals do not have known large populations or small populations that equal a large population in high connectivity. Also, in some Management Units, an area may not contain enough habitat to reach the number of territories stated in the Recovery Plan. In these instances, we relied upon the Recovery Plan guidance (recovery strategy, stream identification, and habitat descriptions), flycatcher detections, and local expertise in habitat quality to identify river segments considered essential for the conservation of the species.

The lateral extent of river segments designated as critical habitat represent the riparian zone, which is an area that is most directly influenced by river functions and is anticipated to occur

within the 100-year floodplain. We created these boundaries from existing digital sources and visual interpretation.

Overall, these designated stream segments represent flycatcher habitat known to be occupied at the time of listing and essential areas that have high recovery value. The designated areas support stable and growing breeding populations, provide migration stopover areas, protect against simultaneous catastrophic loss, maintain gene flow, prevent isolation and extirpation, and encourage colonizers to use new areas. All stream segments provide habitat for a wide distribution of flycatcher territories, including areas for population growth to meet numerical and habitat-related recovery goals. The designated areas also support other important flycatcher needs such as migration, dispersal, foraging, and shelter to reach the geographic distribution and habitat-related recovery goals.

We are designating as critical habitat lands that we have determined were occupied at the time of listing and contain sufficient elements of physical or biological features to support life-history processes essential for the conservation of the species (as defined under section 3(5)(A)(i) of the Act), and lands outside of the geographical area occupied at the time of listing that we have determined are essential for flycatcher conservation (as defined under section 3(5)(A)(ii) of the Act). The occupied stream segments are designated based on sufficient elements of physical or biological features being present to support flycatcher life processes. Some segments contain all of the identified elements of physical or biological features and support multiple life processes. Some segments contain only some elements of the physical or biological features necessary to support the flycatcher's particular use of that habitat.

Final Critical Habitat Designation

We are designating stream segments in 24 Management Units found in six Recovery Units as flycatcher critical habitat. Following our evaluation and analysis under section 4(b)(2) of the Act, stream segments in five Management Units (Owens, Middle Colorado, Hoover to Parker Dam, Parker Dam to Southerly International Border, and Lower Rio Grande Management Units) where recovery goals occur and critical habitat was proposed were excluded in their entirety (see Exclusions section). The designated stream segments occur in California, Nevada, Utah, Colorado, Arizona and New Mexico and include a total of approximately 1,975 km (1,227 mi) of streams. The following list represents the names of the portions of streams that are being designated as flycatcher critical habitat organized by Recovery and Management Unit. In order to help further understand the location of these designated stream segments, please see the associated maps found within the Regulation Promulgation section of this final rule.

Coastal California Recovery Unit in California

(1) Santa Ynez Management Unit—Santa Ynez River and Mono Creek.

(2) Santa Clara Management Unit—Santa Clara River, Ventura River, Piru Creek, Castaic Creek, Big Tujunga Canyon, and San Gabriel River.

(3) Santa Ana Management Unit—Bear Creek, Mill Creek, Oak Glen Creek, San Timoteo Creek, Santa Ana River (including portions of Prado Basin), Waterman Creek, and Bautista Creek.

(4) San Diego Management Unit—Santa Margarita River, DeLuz Creek, San Luis Rey River, Pilgrim Creek, Agua Hedionda Creek, Santa Ysabel Creek, Temescal Creek, Temecula Creek, Sweetwater River, and San Diego River.

Basin and Mojave Recovery Unit in California and Nevada

(5) Kern Management Unit—South Fork Kern River (including upper Lake Isabella) and Canebrake Creek, California.

(6) Mojave Management Unit—Deep Creek, Holcomb Creek, Mojave River, and West Fork Mojave River, California.

(7) Salton Management Unit—San Felipe Creek and Mill Creek, California.

(8) Amargosa Management Unit—Willow Creek, California; Amargosa River, California and Nevada; and five separate riparian areas within Ash Meadows National Wildlife Refuge, Nevada.

Lower Colorado Recovery Unit in Nevada, California and Arizona Border, Arizona, Utah, and New Mexico

(9) Little Colorado Management Unit—Little Colorado River and West Fork Little Colorado River, Arizona.

(10) Virgin Management Unit—Virgin River, Nevada, Arizona, and Utah.

(11) Pahranagat Management Unit—Pahranagat River, Nevada.

(12) Bill Williams Management Unit— Big Sandy River, Bill Williams River, and Santa Maria Rivers (including upper Alamo Lake), Arizona.

Upper Colorado Recovery Unit in Arizona, Utah, Colorado, and New Mexico

(13) San Juan Management Unit—Los Pinos River, Colorado; San Juan River (north bank), Utah.

(14) Powell Management Unit—Paria River, Utah.

Gila Recovery Unit in Arizona and New Mexico

(15) Verde Management Unit—Verde River, Arizona.

(16) Roosevelt Management Unit—Salt River and Tonto Creek, Arizona.

(17) Middle Gila and San Pedro Management Unit—Gila River and San Pedro River, Arizona.

(18) Upper Gila Management Unit—Gila River in Arizona and New Mexico.

(19) Santa Cruz Management Unit—Santa Cruz River, Empire Gulch, and Cienega Creek, Arizona.

(20) San Francisco Management Unit—San Francisco River, Arizona and New Mexico.

(21) Hassayampa and Agua Fria Management Unit—Hassayampa River, Arizona.

Rio Grande Recovery Unit in New Mexico and Colorado

(22) San Luis Valley Management Unit—Conejos River and Rio Grande, Colorado.

(23) Upper Rio Grande Management Unit—Coyote Creek, Rio Grande, Rio Grande del Rancho, and Rio Fernando, New Mexico.

(24) Middle Rio Grande Management Unit—Rio Grande, New Mexico.

Table 1 below lists all the streams included in this revised designation and whether they are considered occupied at the time of listing and whether they are currently considered occupied.

We note which streams were within the geographical area known to be occupied at time of listing, based upon our criteria (1991-1994), and are therefore being designated under section 3(5)(A)(i) of the act because they contain essential physical or biological features that require special management or protections. Streams not known to be occupied at the time of listing are being designated as critical habitat under section 3(5)(A)(ii) of the act because they are essential for the conservation of the species. We also note which streams have had flycatcher territories detected between 1991 and 2010.

TABLE 1—Portion of Streams Designated for Flycatcher Critical Habitat

Recovery unit

Management unit

Portion of streams

Known to be occupied at time of listing (1991-1994)

Territories detected (1991-2010)

Coastal California

Santa Ynez

Mono Creek

No

No.

Santa Ynez River

Yes

Yes.

Santa Clara

Big Tujunga Canyon

No

No.

Castaic Creek

No

No.

Piru Creek

No

Yes.

San Gabriel River

No

Yes.

Santa Clara River

Yes

Yes.

Ventura River

No

No.

Santa Ana

Bautista Creek

No

Yes.

Bear Creek

No

Yes.

Mill Creek

No

Yes.

Oak Glen Creek

No

Yes.

San Timoteo Creek

No

Yes.

Santa Ana River

No

Yes.

Waterman Creek

No

Yes.

San Diego

Agua Hedionda Creek

No

Yes.

DeLuz Creek

No

Yes.

Pilgrim Creek

Yes

Yes

San Diego River

No

Yes.

San Luis Rey River

Yes

Yes.

Santa Margarita River

No

Yes.

Santa Ysabel Creek

No

Yes.

Sweetwater River

No

Yes.

Temecula Creek

No

Yes.

Temescal Creek

No

No.

Basin and Mojave

Kern

Canebrake Creek

No

Yes.

South Fork Kern River

Yes

Yes.

Mohave

Deep Creek

No

No.

West Fork Mojave River

No

No.

Holcomb Creek

No

Yes.

Mojave River

No

Yes.

Salton

Mill Creek

No

Yes.

San Felipe Creek

No

Yes.

Amargosa

Amargosa River

No

Yes.

Willow Creek

No

No.

Ash Meadows Riparian Areas

No

Yes.

Lower Colorado

Little Colorado

Little Colorado River

Yes

Yes.

West Fork Little Colorado River

No

No.

Virgin

Virgin River

No

Yes.

Pahranagat

Pahranagat River

No

Yes.

Bill Williams

Big Sandy River

Yes

Yes.

Bill Williams River

Yes

Yes.

Santa Maria River

Yes

Yes.

Upper Colorado

San Juan

San Juan River

No

Yes.

Los Pinos River

No

Yes.

Powell

Paria River

No

No.

Gila

Verde

Verde River

Yes

Yes.

Roosevelt

Tonto Creek

Yes

Yes.

Salt River

Yes

Yes.

Middle Gila and San Pedro

San Pedro River

Yes

Yes.

Gila River

Yes

Yes.

Upper Gila

Gila River

Yes

Yes.

Santa Cruz

Santa Cruz River

No

No.

Cienega Creek

No

Yes.

Empire Gulch

No

Yes.

San Francisco

San Francisco River

Yes

Yes.

Hassayampa and Agua Fria

Hassayampa River

No

Yes.

Rio Grande

San Luis Valley

Rio Grande

Yes

Yes.

Conejos River

No

Yes.

Upper Rio Grande

Coyote Creek

Yes

Yes.

Rio Fernando

No

Yes.

Rio Grande

Yes

Yes.

Rio Grande Del Rancho

Yes

Yes.

Middle Rio Grande

Rio Grande

Yes

Yes.

Approximate land ownership in each State where the designated critical habitat occurs is provided below in Table 2.

TABLE 2—Land Ownership, by State, of Revised Designated Critical Habitat Areas for Southwestern Willow Flycatcher, Listed as Approximate Stream Lengths in km (mi); and Approximate Area in ha (ac)

State

Federal

State

Private

Other/Unclassified

Total

AZ

365 (227); 9,869 (24,387)

50 (31); 3,012 (7,443)

369 (229); 19,436 (48,026)

0 (0); 0 (0)

784 (487); 32,317 (79,856).

CA

188 (117); 2,688 (6,642)

26 (16); 619 (1,529)

78 (48); 1,089 (2,692)

316 (196); 11,470 (28,342)

609 (378); 15,866 (39,205).

CO

43 (27); 4,063 (10,040)

0 (0); 0 (0)

7 (5); 221 (547)

0 (0); 0 (0)

51 (31); 4,284 (10,586).

NV

29 (18); 1,451 (3,584)

7 (4); 649 (1,603)

19 (12); 1,383 (3,416)

0 (0); 0 (0)

54 (34); 3,482 (8,603).

NM

125 (78); 6,318 (15,613)

29 (18); 4,780 (11,812)

248 (154); 14,817 (36,613)

0 (0); 0 (0)

402 (250); 25,916 (64,039).

UT

41 (25); 1,544 (3,816)

0 (0); 15 (38)

35 (22); 1,146 (2,831)

0 (0); 0 (0)

76 (47); 2,705 (6,685).

Total

791 (492); 25,933 (64,082)

112 (69); 9,075 (22,424)

756 (470); 38,091 (94,125)

316 (196); 11,470 (28,342)

1,975 (1,227); 84,569 (208,973).

Notes:

No tribal lands were included in the final revised designation. Totals do not sum because some stream segments have different ownership on each side of the bank resulting in those segments being counted twice. Other/Unclassified includes some local government ownership and unclassified segments (where land ownership was not available).

Critical Habitat Unit Descriptions

We present brief descriptions below of all critical habitat units and reasons why they meet the definition of critical habitat for the flycatcher. The units are organized by Recovery Unit and then Management Unit. For each Recovery Unit we provide a broad overview of the recent distribution and abundance of flycatcher territories. Based upon our criteria, we also specifically list those streams designated as critical habitat within that Recovery Unit that were known to be occupied by flycatchers at the time of listing, and possess the physical or biological features that may require special management considerations or protection. Detailed site and territory summary information used for Recovery and Management Units are primarily generated from the USGS Rangewide Database (Sogge and Durst 2008, entire) and Flycatcher Rangewide Report (Durst

et al.

2008, entire).

Because of the abundance of information presented in each Management Unit description, this paragraph is a brief overview of the order of information presented in each unit description. For each Management Unit, we begin by stating the numerical territory goal described in the Recovery Plan and, in many instances, a brief note about flycatcher territory distribution. We next explain whether the Management Unit supported a large flycatcher nesting population (as defined in the

Criteria Used To Identify Critical Habitat,

“Areas with Large Populations” section) in order to establish the areas where we initially focused our selection of stream segments to propose as critical habitat. For Management Units where there was a large population, we provide more specific information about the occurrence of flycatcher territories within that large population area. If there was no known large flycatcher nesting population, we provide information about known flycatcher distribution and abundance with that Management Unit. We next present those stream segments we are designating as critical habitat and appropriate location and length descriptions. Any stream segments we designate that were not known to be occupied at the time of listing, we described as an “essential” segment for flycatcher conservation in order to reach the stated recovery goals for this Management Unit. We reiterate the description of those designated segments that were known to be occupied by flycatchers at the time of listing. Finally, we explain how the critical habitat designation of stream segments supports the science and conservation goals established in the Recovery Plan, and for those streams not occupied at the time of listing, we offer information supporting why they are considered essential for flycatcher conservation.

For each stream segment being designated as critical habitat, we identify the State and County where it occurs and list the stream length being designated rounded up to the nearest tenth of a kilometer and mile. The specific beginning and ending points of each designated stream segment can be found below in the combination of textual descriptions and associated maps for each critical habitat unit in the Regulation Promulgation section of this document. In addition, GIS data for all designated stream segments, which include more specific lateral extent critical habitat information, may be downloaded online at

http://www.fws.gov/southwest/es/arizona/southwes.htm

. We also note in our descriptions which stream segments which were proposed for critical habitat were exempted under section 4(a)(3) under the Act or were excluded from critical habitat under section 4(b)(2) of the Act. For more explanation of why any stream is being exempted or excluded, see the discussions under the Exemptions and Exclusions sections below.

All of the designated stream segments provide flycatcher habitat for breeding, feeding, sheltering, and migration, and subsequently provide metapopulation stability, gene flow of the subspecies, protection against catastrophic population losses, and connectivity between neighboring Management Units and Recovery Units (Service 2002, pp. 74-75, 86-92). They also provide habitat to help meet the numerical and habitat-related goals identified in the Recovery Plan (Service 2002, pp. 77-92). Most of the segments are a subset of those identified in the Recovery Plan as areas that provide substantial recovery value (Service 2002, pp. D-12-D-15). Since completion of the Recovery Plan, additional segments of substantial recovery value have been identified through continued survey, analysis, and habitat evaluation, and have been included in this designation when needed to reach recovery goals. The distribution and abundance of territories and habitat within each designated segment are expected to shift over time as a result of natural disturbance events such as flooding that reshape floodplains, river channels, and riparian habitat (Service 2002, pp. 18, D-11-D-13, D-15).

Coastal California Recovery Unit

This Recovery Unit stretches along the coast of southern California from just north of Point Conception south to

the Mexico border. In 2002, 167 flycatcher territories were estimated to occur in this Recovery Unit (14 percent of the rangewide total) (Sogge

et al.

2003); however the most recent 2007 rangewide assessment estimated that the number of territories has declined to 120 (9 percent of rangewide total) (Durst

et al.

2008, p. 12). Since the completion of the Recovery Plan, territories have been distributed along 15 relatively small watersheds, mostly in the southern third of the Recovery Unit (Service 2002, p. 64; Sogge and Durst 2008). Unlike most other Recovery Units, the Coastal California Unit possesses many streams in proximity to one another. However, most breeding sites are small (fewer than five territories); the largest populations occur along the San Luis Rey, Santa Margarita, and Santa Ynez Rivers (Service 2002, p. 64). In 2001, all territories occurred in habitats dominated by native plants, and over 60 percent were on government-managed lands (Federal, State, and local) (Service 2002, p. 64). This Recovery Unit contains the Santa Ynez, Santa Clara, Santa Ana, and San Diego Management Units. The stream segments designated as critical habitat are described below under their appropriate Management Units.

Based upon our occupancy criteria (see above) within the Coastal California Recovery Unit, the Santa Ynez (1991), Santa Clara (1994), and San Luis Rey (1993) Rivers, and Pilgrim Creek (1994) ar

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