10694 Federal Register / Vol. 60, No. 38 / Monday, February 27, 1995 / Rules and Regulations

DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

RIN 1018 AB97

Endangered and Threatened Wildlife

and Plants; Final Rule Determining

Endangered Status for the

Southwestern Willow Flycatcher

AGENCY: Fish and Wildlife Service,

Interior.

ACTION: Final rule.

SUMMARY: The Fish and Wildlife Service

(Service) determines the southwestern

willow flycatcher (Empidonax traillii

extimus) to be an endangered species

under the authority of the Endangered

Species Act of 1973, as amended (Act).

The breeding range of this bird includes

southern California, southern Nevada,

southern Utah, Arizona, New Mexico,

western Texas, southwestern Colorado,

and extreme northwestern Mexico.

Within this region, the species is

restricted to dense riparian associations

of willow, cottonwood, buttonbush, and

other deciduous shrubs and trees. This

habitat was historically rare and

sparsely distributed and is currently

more rare owing to extensive

destruction and modification. The

southwestern willow flycatcher is

endangered by extensive loss of habitat,

brood parasitism, and lack of adequate

protective regulations. This rule

implements Federal protection provided

by the Act for the southwestern willow

flycatcher. Designation of critical habitat

for the southwestern willow flycatcher

is deferred while the Service gathers

further comments and reconsiders the

prudence of designation and the

appropriate boundaries of any area to be

designated.

DATES: The listing of the southwestern

willow flycatcher is effective March 29,

1995. Comments on the designation of

critical habitat may be submitted until

April 28, 1995.

ADDRESSES: The complete file for this

rule is available for inspection, by

appointment, during normal business

hours at Ecological Services State

Office, U.S. Fish and Wildlife Service,

2321 West Royal Palm Road, Suite 103,

Phoenix, Arizona 85021.

FOR FURTHER INFORMATION CONTACT: Sam

F. Spiller or Robert M. Marshall at the

above address (Telephone 602/640–

2720).

SUPPLEMENTARY INFORMATION:

Background

The southwestern willow flycatcher is

a small bird, approximately 15

centimeters (cm) (5.75 inches) long. It

has a grayish-green back and wings,

whitish throat, light grey-olive breast,

and pale yellowish belly. Two wingbars

are visible; the eye ring is faint or

absent. The upper mandible is dark, the

lower is light. The song is a sneezy ‘‘fitzbew’’ or ‘‘fit-za-bew,’’ the call a repeated

‘‘whitt.’’

The southwestern willow flycatcher

occurs in riparian habitats along rivers,

streams, or other wetlands, where dense

growths of willows (Salix sp.),

Baccharis, arrowweed (Pluchea sp.),

buttonbush (Cephalanthus sp.),

tamarisk (Tamarix sp.), Russian olive

(Eleagnus sp.) or other plants are

present, often with a scattered overstory

of cottonwood (Populus sp.) (Grinnell

and Miller 1944, Phillips 1948, Phillips

et al. 1964, Whitmore 1977, Hubbard

1987, Unitt 1987, Whitfield 1990,

Brown and Trosset 1989, Brown 1991,

Sogge et al. 1993, Muiznieks et al.

1994). Throughout the range of E. t.

extimus, these riparian habitats tend to

be rare, widely separated, small and/or

linear locales, separated by vast

expanses of arid lands. The

southwestern willow flycatcher has

experienced extensive loss and

modification of this habitat and is also

endangered by other factors, including

brood parasitism by the brown-headed

cowbird (Molothrus ater) (Unitt 1987,

Ehrlich et al. 1992, Sogge et al. 1993,

Muiznieks et al. 1994).

The southwestern willow flycatcher

(Order Passeriformes; Family

Tyrannidae) is a subspecies of one of the

ten North American flycatchers in the

genus Empidonax. The willow

flycatcher and alder flycatcher (E.

alnorum) were once considered a single

species, the Traill’s flycatcher (E.

traillii). Some sources [American

Ornithologists’ Union (AOU) 1983,

McCabe 1991] treat E. traillii and E.

alnorum, and all their subspecies as a

superspecies, the ‘‘traillii complex’’.

However, the two species are

distinguishable by morphology (Aldrich

1951), song type, habitat use, structure

and placement of nests (Aldrich 1953),

eggs (Walkinshaw 1966), ecological

separation (Barlow and McGillivray

1983), and genetic distinctness (Seutin

and Simon 1988). The breeding range of

the alder flycatcher generally occurs

north of the willow flycatcher’s range.

The southwestern willow flycatcher is

one of five subspecies of the willow

flycatcher currently recognized

(Hubbard 1987, Unitt 1987, Browning

1993) (Figure 1.). The breeding ranges of

the widely distributed E. t. traillii and

E. t. campestris extend across the

northern United States and southern

Canada, from New England and Nova

Scotia west, through northern Wyoming

and Montana, and into British

Columbia. Hubbard (1987) and Unitt

(1987) treated E. t. campestris as

synonymous with E. t. traillii, but

Browning (1993) considered them

separate subspecies (Figure 1.). The

subspecies E. t. adastus breeds from

Colorado west of the plains, west

through the Great Basin States and into

the eastern portions of California,

Oregon and Washington. The breeding

range of E. t. brewsteri extends from the

central California coast north, through

western Oregon and Washington to

Vancouver Island. The breeding range of

the southwestern willow flycatcher (E. t.

extimus) includes southern California,

southern Nevada, southern Utah,

Arizona, New Mexico, and western

Texas (Hubbard 1987, Unitt 1987,

Browning 1993). It may also breed in

southwestern Colorado, but nesting

records are lacking. Records of probable

breeding E. t. extimus in Mexico are few

and are restricted to extreme northern

Baja California del Norte and Sonora

(Unitt 1987, Wilbur 1987).

BILLING CODE 4310–55–M
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BILLING CODE 4310–55–C
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The willow flycatcher subspecies are

distinguished primarily by subtle

differences in color and morphology.

Unitt (1987) noted that these differences

‘‘* * * are minor, but differ little in

magnitude from those distinguishing the

species E. traillii from E. alnorum. In

Empidonax, small differences in

morphology may mask large differences

in biology.’’

The subspecies E. t. extimus was

described by A.R. Phillips (1948) from

a collection by G. Monson from the

lower San Pedro River in southeastern

Arizona. The taxonomy of E. t. extimus

was critically reviewed by Hubbard

(1987), Unitt (1987), and Browning

(1993). Hubbard (1987) gave a qualified

endorsement of the validity of E. t.

extimus, recommending continued

examination of the taxonomy. Unitt

(1987) found that E. t. extimus was

distinguishable from other willow

flycatchers by color, being paler, and

morphology (primarily wing formula)

but not overall size. Browning (1993)

also found that E. t. extimus was

distinguishable as a more pale-colored

subspecies. The song dialect of E. t.

extimus may also be distinguishable

from other willow flycatchers. Rather

than the crisp, sneezy ‘‘fitz-bew’’ of the

northerly subspecies, E. t. extimus sings

a more protracted, slurred ‘‘fit-za-bew,’’

with a burry ‘‘bew’’ syllable (recordings

by M. Sogge and J. Travis). The

subspecies E. t. extimus is accepted by

most authors (e.g., Aldrich 1951, Behle

and Higgins 1959, Phillips et al. 1964,

Bailey and Niedrach 1965, Oberholser

1974, Monson and Phillips 1981, Harris

et al. 1987, Schlorff 1990, Harris 1991).

Section 3(15) of the Act and regulations

at 50 CFR 424.02(k) defines the term

‘‘species’’ as any subspecies of fish or

wildlife or plants, and any distinct

population segment of any vertebrate

species which interbreeds when mature.

Based on the above information, the

Service has determined that E. t.

extimus is eligible for protection under

the Act.

The southwestern willow flycatcher

nests in thickets of trees and shrubs

approximately 4–7 meters (m) (13–23

feet) or more in height, with dense

foliage from approximately 0–4 m (13

feet) above ground, and often a high

canopy cover percentage. The diversity

of nest site plant species may be low

(e.g., willows) or comparatively high

(e.g., mixtures of willow, buttonbush,

cottonwood, boxelder, Russian olive,

Baccharis, and tamarisk). Nest site

vegetation may be even- or uneven-aged,

but is usually dense and structurally

homogeneous (Brown 1988, Whitfield

1990, Sogge et al. 1993, Muiznieks et al.

1994). Historically, E. t. extimus nested

primarily in willows, buttonbush, and

Baccharis, with a scattered overstory of

cottonwood (Grinnell and Miller 1944,

Phillips 1948, Whitmore 1977, Unitt

1987). Following modern changes in

riparian plant communities, E. t.

extimus still nests in native vegetation

where available, but has been known to

nest in thickets dominated by tamarisk

and Russian olive (Hubbard 1987,

Brown 1988, Sogge et al. 1993,

Muiznieks et al. 1994). Sedgwick and

Knopf (1992) found that sites selected as

song perches by male willow flycatchers

(E. t. traillii/campestris) exhibited

higher variability in shrub size than did

nest sites and often included large

central shrubs. Habitats not selected for

either nesting or singing were narrower

riparian zones, with greater distances

between willow patches and individual

willow plants. Nesting willow

flycatchers of all subspecies generally

prefer areas with surface water nearby

(Bent 1960, Stafford and Valentine 1985,

Harris et al. 1987), but E. t. extimus

virtually always nests near surface water

or saturated soil (Phillips et al. 1964,

Muiznieks et al. 1994). At some nest

sites surface water may be present early

in the breeding season but only damp

soil is present by late June or early July

(Muiznieks et al. 1994, M. Whitfield,

Kern River Research Center, in litt.-

1993, J. and J. Griffith, Griffith Wildlife

Biology, in litt.-1993). Ultimately, a

water table close enough to the surface

to support riparian vegetation is

necessary.

Defining a minimum habitat patch

size required to support a nesting pair

of E. t. extimus is difficult. Throughout

its range, determining the capability of

habitat patches to support southwestern

willow flycatchers is confused by the

species’ rarity, unstable populations,

variations in habitat types, and other

factors. However, the available

information indicates that habitat

patches as small as 0.5 hectare (ha) (1.23

acres) can support one or two nesting

pairs. Sogge et al. (1993) found

territorial flycatchers in habitat patches

ranging from 0.5 to 1.2 ha (1.23 to 2.96

acres). Two habitat patches of 0.5 and

0.9 ha (1.23 and 2.2 acres) each

supported two territories. Muiznieks et

al. (1994) also reported groups of

territorial E. t. extimus in habitat

patches of approximately one to several

hectares.

The nest is a compact cup of fiber,

bark, and grass, typically with feathers

on the rim, lined with a layer of grass

or other fine, silky plant material, and

often has plant material dangling from

the bottom (Harrison 1979). It is

constructed in a fork or on a horizontal

branch, approximately 1–4.5 m (3.2–15

feet) above ground in a medium-sized

bush or small tree, with dense

vegetation above and around the nest

(Brown 1988, Whitfield 1990,

Muiznieks et al. 1994).

The southwestern willow flycatcher is

present and singing on breeding

territories by mid-May, although its

presence and status is often confused by

the migrating individuals of northern

subspecies passing through E. t. extimus

breeding habitat [D. Kreuper, Bureau of

Land Management (BLM), unpubl. data].

The southwestern willow flycatcher

builds nests and lays eggs in late May

and early June and fledges young in

early to mid-July (Willard 1912, Ligon

1961, Brown 1988, Whitfield 1990,

Sogge and Tibbitts 1992, Sogge et al.

1993, Muiznieks et al. 1994). Some

variation in these dates has been

observed (Carothers and Johnson 1975,

Brown 1988, Muiznieks et al. 1994) and

may be related to altitude, latitude, and

renesting.

The southwestern willow flycatcher is

an insectivore. It forages within and

above dense riparian vegetation, taking

insects on the wing or gleaning them

from foliage (Wheelock 1912, Bent

1960). It also forages in areas adjacent to

nest sites, which may be more open (M.

Sogge, National Biological Survey, pers.

comm. 1993). No information is

available on specific prey species.

The migration routes and wintering

grounds of E. t. extimus are not well

known. Empidonax flycatchers rarely

sing during fall migration, so that a

means of distinguishing subspecies is

not available (Blake 1953, Peterson and

Chalif 1973). However, willow

flycatchers have been reported to sing

and defend winter territories in Mexico

and Central America (Gorski 1969,

McCabe 1991). The southwestern

willow flycatcher most likely winters in

Mexico, Central America, and perhaps

northern South America (Phillips 1948,

Peterson 1990). However, the habitats it

uses on wintering grounds are

unknown. Tropical deforestation may

restrict wintering habitat for this and

other neotropical migratory birds (Finch

1991, Sherry and Holmes 1993).

Breeding bird survey data for 1965

through 1979 combined the willow and

alder flycatchers into a ‘‘Traill’s

flycatcher superspecies’’, because of

taxonomic uncertainty during the 15-

year reporting period. These data

showed fairly stable numbers in central

and eastern North America but strong

declines in the West, the region

including the range of the southwestern

willow flycatcher, and where the alder

flycatcher is absent (Robbins et al.

1986).
Federal Register / Vol. 60, No. 38 / Monday, February 27, 1995 / Rules and Regulations 10697

Unitt (1987) reviewed historical and

contemporary records of E. t. extimus

throughout its range, determining that it

had ‘‘declined precipitously,’’ and that

‘‘although the data reveal no trend in

the past few years, the population is

clearly much smaller now than 50 years

ago, and no change in the factors

responsible for the decline seem likely.’’

Data are now available that indicate

continued declines, poor reproductive

performance, and/or continued threats

for most remaining populations (Brown

1991, Whitfield and Laymon, Kern River

Research Center, in litt. 1993, Sogge and

Tibbitts 1992, Sogge et al. 1993,

Muiznieks et al. 1994).

Previous Federal Actions

The Service included the

southwestern willow flycatcher on its

Animal Notice of Review as a category

2 candidate species on January 6, 1989

(54 FR 554). A category 2 species is one

for which listing may be appropriate but

for which additional biological

information is needed. After soliciting

and reviewing additional information,

the Service elevated E. t. extimus to

category 1 candidate status on

November 21, 1991 (56 FR 58804). A

category 1 species is one for which the

Service has on file substantial

information to support listing, but for

which a proposal to list has not been

issued because it is precluded at present

by other listing activity.

On January 25, 1992, a coalition of

conservation organizations (Suckling et

al. 1992) petitioned the Service,

requesting listing of E. t. extimus as an

endangered species under the Act. The

petitioners also requested emergency

listing and designation of critical

habitat. On September 1, 1992, the

Service published a finding (57 FR

39664) that the petition presented

substantial information indicating that

listing may be warranted and requested

public comments and biological data on

the species. On July 23, 1993, the

Service published a proposal (58 FR

39495) to list E. t. extimus as

endangered with critical habitat, and

again requested public comments and

biological data on the southwestern

willow flycatcher.

Summary of Comments and

Recommendations

In the July 23, 1993, proposed rule (58

FR 39495) and associated notifications,

all interested parties were requested to

submit comments or information that

might bear on whether to list the

southwestern willow flycatcher. The

comment period was originally

scheduled to close October 21, 1993,

then was extended to November 30,

1993. Appropriate State agencies,

county governments, Federal agencies,

scientific organizations, and other

interested parties were contacted and

requested to comment. Newspaper

notices inviting public comment were

published in the following newspapers;

In California, Los Angeles Times, L.A.

Watts Times, Kern Valley Sun, and San

Diego Union-Tribune; in Arizona,

Arizona Daily Sun, Arizona Republic,

Tucson Daily Citizen, White Mountain

Independent, and Arizona Daily Star; in

New Mexico, Albuquerque Journal,

Albuquerque Tribune, Santa Fe New

Mexican, Carlsbad Current-Argus, Silver

City Daily Press; in Nevada, Las Vegas

Sun; in Colorado, Durango Herald; in

Utah, Daily Spectrum; and in Texas, El

Paso Times. The inclusive dates of

publications were August 31 through

September 13, 1993, for the initial

comment period and October 28

through November 5, 1993, for the

public hearings and extension of public

comment period.

The Service held six public hearings.

Because of anticipated interest in the

proposed rule, the Service announced

its intention to hold at least three public

hearings. In response to requests from

the public, three additional hearings

were scheduled. A notice of the hearing

dates and locations was published in

the Federal Register on October 18,

1993 (58 FR 53702). Approximately 424

people attended the hearings. About 17

people attended the hearing in Tucson,

Arizona; 27 in Flagstaff, Arizona; 10 in

Las Cruces, New Mexico; 12 in

Albuquerque, New Mexico; 350 in Lake

Isabella, California; and 8 in San Diego,

California. Transcripts of these hearings

are available for inspection (see

ADDRESSES).

A total of 3,102 written comment

letters were received at the Service’s

Ecological Services State Office in

Arizona: 264 supported the proposed

listing; 2,650 opposed the proposed

listing; and 188 expressed neither

support nor opposition, but either

commented on information in the

proposed rule, provided additional

information, or were non-substantive or

irrelevant to the proposed listing.

Oral or written comments were

received from 62 parties at the hearings:

8 supported the proposed listing; 40

opposed the proposed listing; and 14

expressed neither support nor

opposition but provided additional

information, or were non-substantive or

irrelevant to the proposed listing.

In total, oral or written comments

were received from 31 Federal and State

agencies and officials, 17 local officials,

and 3,116 private organizations,

companies, and individuals. All

comments received during the comment

period are addressed in the following

summary. Comments of a similar nature

are grouped into a number of general

issues.

Issue 1: The American Ornithologists’

Union (AOU) did not list E. t. extimus

in its latest Checklist of North American

Birds; Unitt (1987) could not distinguish

E. t. extimus by color or morphology;

genetic analysis is necessary to

distinguish subspecies; significant

disagreement exists among scientists

regarding taxonomy, for example,

McCabe (1991) did not recognize E. t.

extimus; the willow flycatcher

subspecies, in fact the North American

Empidonax flycatcher species are too

difficult to distinguish to make it

reasonable to list subspecies of those

species; hybridization of the willow

flycatcher subspecies occurs; subspecies

are not worth listing; E. t. extimus is a

subspecies of a very common species; E.

t. extimus is not worth listing because

it is one of nine common species in the

genus Empidonax; this subspecies and

subspecies in general are of minor

ecological value; their loss would be

unimportant; there is little value in

preserving rare species/subspecies; and

historical taxonomic questions may

confuse population trend information.

Service Response: The Service has

determined that E. t. extimus is a valid

taxon. The Service relies on the most

current and authoritative data available

in making decisions regarding the

validity of species, subspecies, or

distinct vertebrate population segments.

These data include articles published in

professional journals, agency reports,

and other unpublished data provided by

researchers. For the southwestern

willow flycatcher, the Service reviewed

this information and found a majority

opinion that E. t. extimus is a valid

subspecies. Authorities who critically

examined the taxonomy of E. traillii and

recognized E. t. extimus include Phillips

(1948), Aldrich (1951), Hubbard (1987),

Unitt (1987), and Browning (1993).

Other authorities accepting the

subspecies include Behle and Higgins

(1959), Phillips et al. (1964), Bailey and

Niedrach (1965), Oberholser (1974),

Monson and Phillips (1981), Harris et al.

(1987), Schlorff (1990), Whitfield (1990),

Brown (1991), Harris (1991), Western

Foundation for Vertebrate Zoology in

litt. 1993, University of California in litt.

1993. The AOU (1983) did not list

subspecies of any bird, including the

willow flycatcher, in its 1983 Checklist

of North America Birds. However, this

does not indicate a lack of recognition

of E. t. extimus, or for the concept of

subspecies. The preface to the 1983

Checklist states ‘‘The Committee
10698 Federal Register / Vol. 60, No. 38 / Monday, February 27, 1995 / Rules and Regulations

strongly endorses the concept of the

subspecies * * * and we wish to make

it clear that the omission of separate

listings of subspecies in this edition is

not a rejection of the validity or utility

of this systematic category * * *.’’

The Service noted McCabe’s (1991)

consideration of the willow and alder

(E. alnorum) flycatchers as a single

species, and his reluctance to recognize

willow flycatcher subspecies. McCabe

(1991) provides a thorough review of the

history of E. alnorum and E. traillii

taxonomy, and the questions of

ecological, morphological, and songtype distinction on which this

taxonomic evaluation has been based.

However, the Service agrees with

Sedgwick’s (1993) comments and

McCabe’s own observation that McCabe

(1991) contrasts with the majority

opinion regarding taxonomy of the

willow and alder flycatchers.

After examining 305 study skins,

Unitt (1987) found that while four

subspecies (E. t. traillii, E. t. adastus, E.

t. brewsteri, and E. t. extimus) could be

tentatively separated by the ‘‘75 percent

rule’’ using overall size (wing and tail

lengths and their ratios to one another),

these criteria were not satisfactorily

conclusive. However, he found that the

subspecies could be satisfactorily

distinguished, under the ‘‘75 percent

rule,’’ using color, wing formula

(relative lengths of primary wing

feathers), or both. Browning (1993)

examined 270 specimens and found that

all four subspecies, and a fifth (E. t.

campestris) were distinguishable by

color.

The Service acknowledges that

taxonomy of E. traillii races continues to

pose questions and may be revised in

the future. The Service has determined

that E. t. extimus is a sufficiently

distinct entity to be listed under the Act

at the very least as a distinct vertebrate

population [50 CFR § 424.02(k)].

However, the Service accepts the

majority opinion that E. t. extimus is a

valid subspecies and lists it as such.

The Service considers taxonomic

distinctness in assigning priorities for

species listings, but not in determining

whether or not to list species. The Act

authorizes listing of species, subspecies,

or distinct population segments, all of

which have ecological significance.

Issue 2: The southwestern willow

flycatcher is not a riparian obligate

species. It also occurs in open prairie

woodlots, dry and brushy pastures, and

brushy fields or slopes. No surveys of

dry habitats have been done to prove

riparian obligacy. The southwestern

willow flycatcher does not ‘‘invariably’’

nest near surface water.

Service Response: The Service is

unaware of any study, report, or species

account that describes E. t. extimus as

anything but a riparian obligate. No

commenter provided data, studies, or

reports indicating that E. t. extimus

nests outside riparian habitats. Several

commenters cited field guides which

describe the willow flycatcher (all

subspecies) as occurring ‘‘* * * in

drier situations (than the alder

flycatcher) * * *’’ (Peterson 1990),

‘‘* * * on brushy slopes * * *’’

(Robbins et al. 1983), and ‘‘* * * dry,

brushy upland pastures * * *’’

(National Geographic Society 1990). The

Service believes that field guide species

accounts do not constitute the best

available scientific information on

biology, ecology or habitat

requirements. Field guide accounts tend

to be brief and generalized, and in this

case represent habitat use of other

willow flycatcher subspecies, which

occur in more mesic regions. Similarly,

Barlow and McGillivray’s (1983)

description of willow flycatchers (E. t.

campestris/traillii) selecting ‘‘* * * a

more xeric upland habitat * * *’’ in

Ontario, Canada, is not considered

relevant to habitat selection of E. t.

extimus in the desert Southwest. In the

wetter climates of the north, upper

midwest, and northeast, habitat

conditions of moist soil or surface

water, supporting thickets of deciduous

shrubs and trees, are not restricted to

riparian areas. However, in the arid

Southwest where E. t. extimus occurs,

these conditions are limited to riparian

areas, usually in profound contrast to

the adjacent and prevailing desert

conditions. Various authors (e.g., King

1955) have noted that while willow

flycatchers may nest away from riparian

areas in the north and east, in arid

regions (the ranges of E. t. brewsteri and

E. t. extimus particularly) the species is

restricted to riparian habitats. Regarding

the presence of surface water during the

breeding season, new information was

provided indicating that some nest sites

have surface water in close proximity

early in the breeding season, which

recedes underground by the end of the

breeding season. At these sites, the

water table remains at least high enough

to sustain riparian vegetation. The

Service is unaware of any surveys

performed in non-riparian habitats

specifically to verify the absence of

nesting E. t. extimus. However, the

Service relied on local, State, and

regional species accounts of distribution

and habitat use, none of which describe

occurrence outside of riparian habitats.

Issue 3: The loss and modification of

southwestern riparian habitat is

overstated, poorly documented, and

does not constitute a threat to the

flycatcher; the statement that 90 percent

loss of riparian habitat has occurred is

inaccurate and an exaggeration; riparian

habitat has not decreased, but increased

as a result of diversions, irrigation, etc;

habitat has increased, not decreased, in

local area(s) over the past 20 years;

riparian regeneration is approaching

1,000 percent in southeastern Arizona;

Hastings and Turner (1965) show that

cottonwood riparian habitat has

increased in southeastern Arizona; the

upper San Pedro River is recovered, not

‘‘unsuitable and unoccupied’’ as the

Service claimed; because tamarisk has

increased, and E. t. extimus uses

tamarisk, tamarisk invasion does not

constitute modification of habitat, but

expansion of habitat; population

declines in the past 20 years are

concurrent with improved riparian

habitats, so no correlation exists

between trends in habitat and

populations; the proposal fails to

support claims that urban development,

agriculture, and livestock grazing are

harmful to the flycatcher.

Service Response: The Service has

determined that the documentation of

loss and modification of southwestern

riparian habitats, cited in this final rule,

is adequate. Regarding the ‘‘90 percent

loss and modification’’ statement, the

proposed rule stated that ‘‘* * * as

much as 90 percent * * *’’ (emphasis

added) has been lost or modified. The

actual percentage lost or modified is not

expected to be consistent across the

region, but should vary with elevation,

rainfall, geographic area, relative size of

drainage system, and severity of

impacts. Loss and modification may be

lesser at higher elevations, where

precipitation is greater and evaporation

less. In most major lower elevation

desert riparian systems, loss or

modification may in fact be near 100

percent, e.g., the lower Colorado, lower

Gila, lower Rio Grande, and lower Salt

Rivers. Because ‘‘modification’’ includes

alterations in flow regimes, channel

confinement, changes in water quality,

and floristic makeup of riparian

systems, the Service believes it is not a

misrepresentation to state that up to 90

percent of southwestern riparian

ecosystems have been lost or modified.

Commenters stating that riparian

habitat has not decreased, but increased

as a result of diversions and irrigation,

presented no supporting information.

The Service recognizes that some

diversions, particularly unmaintained

irrigation ditches, sometimes support

riparian vegetation. However, the

Service believes diversion and irrigation

result in a net loss of riparian habitat.
Federal Register / Vol. 60, No. 38 / Monday, February 27, 1995 / Rules and Regulations 10699

Where riparian vegetation becomes

established along irrigation systems, it is

often cleared away at regular intervals.

Where it is not, it is sometimes because

an artificially created riparian/wetland

habitat is being maintained as

mitigation or compensation for loss of

natural riparian habitat elsewhere.

The Service recognizes that in some

local areas in recent decades, riparian

habitat has been rehabilitated or

increased, not decreased. However, the

Service accepts the consensus of

literature cited in this rule that the

overall trend continues to be one of

habitat loss.

Hastings and Turner (1965) and Bahre

(1991) noted that riparian habitats were

already significantly altered by the turn

of the last century. Hastings and Turner

(1965) also noted that all major

watercourses in southern Arizona

suffered entrenchment and became

more ephemeral in flow in

approximately 1890. Land use practices

that had already affected riparian

habitats in this Arizona-Mexico border

region included livestock grazing,

woodcutting, and water diversion;

climatic changes may also have

contributed. The differences between

the historic and more recent

photographs show some riparian

recovery, concurrent with reductions in

livestock stocking levels from their

highs in the late 1800’s. No data, or

elaboration, were presented to support

statements that riparian regeneration is

approaching 1000 percent in

southeastern Arizona.

As this final rules discusses, E. t.

extimus sometimes nests in tamarisk,

but does so at lower densities, and

apparently at lower success rates than in

native vegetation (Hunter et al. 1988,

Sogge et al. 1993, Muiznieks et al.

1994). Therefore, tamarisk invasion

likely represents replacement of native

habitat with lower-quality habitat,

rather than an increase in habitat

availability. Only in a few unique

situations does tamarisk truly represent

‘‘new’’ habitat. For example, in the

Grand Canyon flycatchers nest in a

‘‘new’’ riparian habitat, dominated by

tamarisk (Carothers and Brown 1991).

This new riparian habitat became

established in the historic flood-scour

zone of the Colorado River, after

construction of Glen Canyon Dam

eliminated annual scouring floods.

However, flycatchers nest in this area in

low numbers (Brown 1991, Sogge and

Tibbitts 1992, Sogge et al. 1993) and

have low nesting success. It is

noteworthy that by forming Lake

Powell, Glen Canyon Dam also

inundated habitat in Glen Canyon. The

southwestern willow flycatcher was

described as a common nester in Glen

Canyon prior to inundation (Behle and

Higgins 1959, Behle 1985), indicating

that this historic habitat was of higher

quality than the new habitat in Grand

Canyon.

Issue 4: The flycatcher has always

been a rare bird, so its rarity now is no

change from historical situations;

historical specimens are few, indicating

the bird was always rare; population

data are insufficient to show decline;

population data are suspect, developed

by parties with agendas of land control/

acquisition; the flycatcher is not

declining in all areas; historical

taxonomic questions may confuse

population trend information; accuracy

or existence of population trend data for

the last 50 years is questionable;

population sampling techniques were

not discussed; these could bias trend

studies; population data are incomplete;

the proposal relies on data reflecting

loss of habitat rather than

comprehensive population trend

analysis; there are no recent collections

of E. t. extimus from southern Arizona

riparian areas.

Service Response: The Service agrees

that the flycatcher has probably always

been sparsely distributed, as a function

of the sparse distribution of its wetland

habitat in a predominantly xeric region.

However, sparse distribution and rarity

are not necessarily equivalent. At

individual locales the flycatcher may

occur in considerable numbers, as

indicated by Herbert Brown’s collection

of 36 nests near Yuma in 1902, and the

persistence of several populations of

considerable numbers (30–40 pairs) in

relatively small areas like the Kern River

Preserve in California (Harris et al.

1986, Whitfield 1990). Although E. t.

extimus habitat is rare, where it is

present nesting pairs may occur in

relatively high densities. This

phenomenon has caused some authors

to describe E. t. extimus as something of

a colonial nester (e.g., Unitt 1987).

Regarding the lack of historic or

recent specimens available from various

parts of the bird’s range, the Service

notes that specimen collection is largely

a function of collecting activity, not

simple presence of the subject.

The Service agrees that, as with many

non-game species, population trend data

are incomplete. No wide scale, and few

local studies have been funded or

undertaken to track this species through

time. Comprehensive, long-term

population data are not necessarily

required for making listing

determinations. Rather, these decisions

often rest upon data on loss and

modification of habitat and other

threats, which are reasonably assumed

to result in population declines. In

many cases, population declines are

inferred from decline in habitat

availability. However, in this and other

listing determinations, the Service seeks

to measure such inference against

whatever population trend data are

available. Regarding concerns over

sources of these data, the Service

endeavors to verify accuracy and

credibility of data. The reports

published by government agencies,

academic institutions, and professional

journals on which this determination is

based are accepted as credible. To

interpret population trends in the light

of changing taxonomic status, the

Service considered all information for

willow flycatchers in the current range

of E. t. extimus to be relevant.

Issue 5: Livestock grazing is not a

threat to E. t. extimus or its habitat;

Montgomery et al. (1985) found 53

singing birds in a grazed area in New

Mexico; on Marine Corps Base Camp

Pendleton, E. t. extimus is increasing

where sheep graze; nest disturbance by

cattle is unsubstantiated; southwestern

flora evolved with large grazing

ungulates; the proposed rule lacks

examples of flycatcher status improving

with reduction in livestock or improved

livestock management; E. t. extimus is

not improving in areas with no grazing;

the proposed rule equates any livestock

grazing with overgrazing, and fails to

distinguish between overgrazing and

well-managed grazing; proper livestock

management is compatible with healthy

riparian habitat; some level of livestock

grazing is compatible with/necessary for

healthy riparian ecosystems; willows

are brush, which cattle don’t eat, but

cattle are blamed for both brush

encroachment and brush destruction;

cattle trample stream banks, which

allows water to escape, creating more

riparian habitat; livestock grazing

prevents urbanization of land, which

would have a greater impact on riparian

habitats.

Service Response: The proposed and

final rules discuss overuse by livestock

as a threat to E. t. extimus, through

impacts on riparian habitat. The Service

recognizes that what constitutes

‘‘overuse’’ varies with differing riparian

ecosystems, elevation, type of livestock,

seasonality of use, and other factors.

The Service believes that some livestock

grazing regimes are likely to be found

compatible with rehabilitation and

maintenance of E. t. extimus habitat.

Montgomery et al. (1985) did not

determine whether the willow

flycatchers they detected on grazed land

were resident E. t. extimus or migrating

individuals of other subspecies. Further,

neither grazing intensity nor nesting
10700 Federal Register / Vol. 60, No. 38 / Monday, February 27, 1995 / Rules and Regulations

success were quantified, so that no

correlations can be made. On Camp

Pendleton, increases in E. t. extimus

were concurrent with livestock (sheep)

grazing but also with an extensive

cowbird trapping program (Griffith and

Griffith 1993). Finally, as discussed in

this rule, examples exist of E. t. extimus

(and other E. traillii subspecies)

numbers and habitat increasing as a

result of grazing reductions or other

improvements in livestock management.

The Service recognizes that

southwestern riparian ecosystems

evolved with native grazing ungulates

(e.g., deer and elk). However, domestic

livestock do not forage, herd or move in

the same manner as native species.

Further, elk occur at higher elevations of

the Southwest, and are absent from the

lowland river systems that constitute

the majority of E. t. extimus habitat.

Issue 6: Timber harvesting is not a

threat to the flycatcher’s riparian

habitat.

Service Response: The proposed rule

noted that the petitioners claimed

timber harvest caused watershed

changes which could result in damage

to riparian habitats through increasing

intensity and frequency of floods. The

petitioners presented no specific

information on this claim. A number of

experimental treatments on

Southwestern forested watersheds have

demonstrated increased peak and flood

flows as a result of timber harvest (Tecle

1991). The degree to which timber

harvesting has affected riparian habitats

inhabited by the willow flycatcher,

however, has not been quantified and is

unknown. The Service did not implicate

timber harvesting in the proposed rule

as a major cause of riparian habitat loss.

Rather, it pointed to that activity as one

of many factors potentially responsible

for riparian habitat loss and

modification. Pending new information

demonstrating otherwise, the Service

still considers timber harvesting a

potential threat to riparian habitat

through loss and modification.

However, the Service does not believe

that this threat exists rangewide, nor

does it believe that timber harvesting

alone is responsible for riparian habitat

loss or the endangered status of the

southwestern willow flycatcher.

All causal factors will be addressed in

the recovery planning process, and

through the Act’s section 7 consultation

process, through which Federal agencies

will be responsible for evaluating the

effects of activities such as timber

harvest on the flycatcher’s riparian

habitat.

Issue 7: Water impoundments have

been beneficial, not detrimental;

fluctuating flows below dams are not

detrimental, in fact have increased

riparian habitat (Glen Canyon Dam

resulted in creation of riparian habitat

in Grand Canyon); impoundments

protect habitat by preventing

catastrophic floods; the proposal had

inadequate discussion of water

impoundments as threat.

Service Response: As discussed

elsewhere in this final rule, water

impoundments have a variety of effects

on riparian habitats. The Service has

determined that, with respect to E. t.

extimus, the net effect of these

influences is negative. For example,

Glen Canyon Dam eliminated massive

annual scouring floods in the Grand

Canyon. This resulted in the

development of a new riparian zone

dominated by tamarisk (Carothers and

Brown 1991). However, flycatchers nest

there in very low numbers and with low

nesting success (Brown 1991, Sogge and

Tibbitts 1992, Sogge et al. 1993). In

contrast, E. t. extimus was described as

a common nester in Glen Canyon (Behle

and Higgins 1959, Behle 1985), prior to

its inundation by Lake Powell.

Issue 8: Comments concerning the

ecology of cowbirds and cowbird

parasitism included the following:

Breeding Bird Survey (BBS) data

indicate that cowbirds have declined,

not increased; the claim that cowbirds

are associated with livestock is not

supported; cowbirds are associated with

deer and elk, not cows; the cowbird

threat is a natural one; there is

inconclusive evidence that cowbird

increases are directly connected with

livestock grazing; cowbird parasitism of

E. t. extimus is known in areas without

livestock grazing (e.g., Grand Canyon,

Kern River); there is no correlation

between livestock grazing in riparian

areas and cowbird parasitism; Taylor

(1986) showed that cowbirds were most

abundant in areas with long-term

livestock exclusion; because flycatchers

and cowbirds are positively associated

(they tend to occur together), flycatchers

can coexist with cowbirds; there is

inconclusive evidence that cowbird

parasitism is responsible for declines in

nesting success; cowbirds have

increased as a result of increases in bird

feeders, campgrounds, etc. and

increases in wintering food/habitat; the

proposed rule cited no studies that

documented cowbird parasitism of E. t.

extimus; citations regarding parasitism

of other species are irrelevant. Section

4(a)(1)(E) of the Act allows listing

species because of ‘‘* * * natural or

manmade factors affecting its continued

existence * * *.’’

Service Response: Cowbird numbers

appear to be declining only in the

northeastern United States and

southeastern Canada. Through the 27

years of the BBS, cowbird populations

have remained fairly stable, with a small

increase in the 1970’s, small decrease in

the 1980’s, and slight increase in recent

years; however, the West has

experienced a marked population

increase over the last five years

(Wiedenfeld 1993).

The association of cowbirds with

domestic livestock is detailed in the

sources cited in this final rule. The

Service has neither found nor been

provided information indicating that

cowbirds are associated with deer or

elk. Other factors, including habitat

fragmentation and urban/suburban

feeding, are likely to have contributed to

increases in cowbirds. These causal

factors will be important to address in

the section 7 consultation process and

the development of recovery actions.

However, it is the threat of parasitism,

regardless of cause, that in part

necessitates listing.

Where high parasitism rates are found

in E. t. extimus nesting locations in

areas with no livestock grazing at the

nest site, there have been livestock

nearby that provide feeding sites in

close enough proximity to facilitate

cowbird parasitism. Cowbirds may

disperse up to 7 kilometers (km) from

their daily feeding/roosting sites to areas

with host species (Rothstein et al. 1984).

At the Kern River Preserve, the riparian

habitat supporting E. t. extimus is not

grazed, but the immediately adjacent

lands are. Similarly, although livestock

grazing does not occur in Grand Canyon

National Park, open range grazing and

an introduced bison herd occur on

adjacent lands. Further, cowbirds

concentrate at pack animal corrals at

various points within the National Park

(Johnson and Sogge 1993). Thus,

flycatcher habitat may be ungrazed but

still be affected by cowbirds, by having

livestock concentrations nearby to serve

as cowbird feeding sites.

Cowbirds and E. t. extimus are

positively associated because cowbirds

require, and therefore associate with,

prospective hosts. The Service finds that

extensive information indicates cowbird

parasitism negatively affects the

southwestern willow flycatcher. This

information includes specific examples

of parasitism of E. t. extimus, cited in

this rule, and examples of the effects of

cowbird parasitism on other rare species

of limited habitat. Recent information

continues to document high parasitism

rates for E. t. extimus (Sogge et al. 1993,

Muiznieks et al. 1994), and increases in

flycatcher reproduction or populations,

concurrent with reductions in cowbird

numbers (Griffith and Griffith 1993, M.

Whitfield in litt.—1993).
Federal Register / Vol. 60, No. 38 / Monday, February 27, 1995 / Rules and Regulations 10701

Issue 9: Tamarisk is not an invader

species, but a successional stage,

becoming established on recentlyscoured areas; livestock do eat tamarisk

for its salt content; the Service needs to

clarify the positive and negative

characteristics of tamarisk; tamarisk

increases habitat availability, in fact

provides high-quality bird habitat.

Service Response: The Service found

no information, and was not provided

any information by commenters,

indicating that tamarisk is primarily a

successional stage vegetation type,

rather than an invasive exotic. This final

rule presents an updated discussion of

tamarisk ecology, supported by

additional literature references. The

Service concurs with the consensus

among published authorities that

tamarisk is an invasive, usually

dominant exotic plant, not a

successional species. Commenters that

stated livestock eat tamarisk for its salt

content provided no supporting

information. The Service’s

understanding of the literature is that

cattle prefer native species over

tamarisk for forage.

As discussed in this rule, E. t. extimus

has been documented nesting in

tamarisk at elevations above

approximately 625 m (2000 feet). Rather

than attempt to present criteria here for

when tamarisk eradication presents a

threat or a positive recovery action, the

Service will address this issue on a caseby-case basis through the section 7

consultation process with other Federal

agencies. This will allow Federal

agencies the flexibility to consider

individual cases in the light of the

specific circumstances surrounding

each one.

Although Brown and Trosset (1989)

suggested that tamarisk provided an

‘‘ecological equivalent’’ to native

vegetation, they qualified this statement.

They noted that their study involved

small sample sizes, and that their

methods differed from Whitmore’s

(1975, 1977), which was their basis for

comparison with native riparian

habitats. Further, Brown and Trosset

(1989) noted that this ‘‘ecological

equivalent’’ function may be most

significant where tamarisk became

established where no native riparian

vegetation existed previously (e.g., the

Colorado River in Grand Canyon).

Issue 10: Herbert Brown’s collection

of 36 nests with eggs from the lower

Colorado River, in 1900 and 1902,

indicates overcollection for science may

have caused declines.

Service Response: The effects of

Brown’s collections on populations over

90 years ago are unknown. These effects

may have been significant. However,

Brown’s collections themselves may

suggest that populations at that time

could sustain such collecting pressure.

The origin of Brown’s collections from

several specific locales suggests that E.

t. extimus was an abundant nesting bird

in the area of the confluence of the Gila

and Colorado rivers. Collection of 36

nests would have impacted

reproduction alone, only for 1902, when

all but one of the nests was collected.

Considering continued habitat loss, and

increasing cowbird populations since

1902, the Service does not believe that

Brown’s collection of 36 nests with eggs

in 1900 and 1902 significantly affects E.

t. extimus populations in 1995.

However, the Service believes that

current flycatcher populations are

unlikely to be able to sustain collecting

pressures like Brown’s activities of

1902. In 1993, extensive surveys of the

region of Brown’s collections located

only four to five territories (Muiznieks

et al. 1994).

Issue 11: Drought has impacted

habitat.

Service Response: The Service

recognizes that extended droughts are

likely to have impacted E. t. extimus

through habitat reduction. This natural

phenomenon and human-induced

habitat impacts may exacerbate one

another’s effects on E. t. extimus habitat.

Issue 12: Predators such as snakes,

hawks, ravens, grackles, and domestic

cats are threats to E. t. extimus.

Service Response: The Service agrees

that these constitute potential predators

of songbirds, including E. t. extimus.

While predation would not normally be

expected to be a major threat to the

flycatcher, its populations may be so

low currently that they cannot

withstand normal predation. Further,

several of these types of predation may

be facilitated by habitat alteration or

other human actions. Therefore, the

Service will address predation in

recovery planning, and other Federal

agencies should consider the effects of

their actions on some of these forms of

predation.

Issue 13: Hikers, elk, deer, and beaver

are threats to flycatcher nests and

habitat; listing would cause restrictions

on fishing and water recreation.

Service Response: No information was

provided to support statements that

hikers constitute a threat to E. t.

extimus. This rule briefly discusses

possible impacts of recreation on E. t.

extimus and its habitat. These impacts

are expected to be primarily effects on

vegetation through soil compaction,

clearing vegetation, and creating trails.

Because E. t. extimus is not a timid

species, disturbance is expected to be an

impact only when continuous intrusive

activities take place near habitat, or

when recreation takes place within or

adjacent to the nest stand. Because nest

stands tend to be very dense, virtually

impenetrable thickets, often with

swampy conditions, recreational

impacts are not expected to occur often.

Elk and deer use riparian habitats for

foraging, but generally behave

differently than domestic livestock.

They tend not to occur in large

concentrations and remain in riparian

areas for long periods like domestic

cattle. The Service is aware that elk can

impact riparian systems when their

numbers reach high levels. However, elk

are lacking from the majority of

southwestern willow flycatcher habitats,

because these riparian areas occur at

lower elevations than elk. Beaver cut

and use willow and cottonwood, but

may also be important in creating quietwater riparian habitats by damming

smaller and steeper creeks.

Issue 14: The presence of unoccupied

habitat indicates that E. t. extimus is not

currently habitat limited.

Service Response: As discussed in

this rule, the Service has determined

that E. t. extimus has suffered extensive

habitat loss, which is complicated by

the current low number of flycatchers,

and reduction of reproductive output

due to brood parasitism by brownheaded cowbirds. The current existence

of apparently suitable habitat that is not

occupied by E. t. extimus more likely

indicates that its numbers are too low to

fill all available habitat. Further, habitat

exists in isolated, fragmented patches.

With low population numbers and

inhibited reproduction, E. t. extimus

may be unable to maintain local

populations, much less be able to

disperse and colonize unoccupied

locales.

Issue 15: Cowbird parasitism is the

main threat to E. t. extimus, not habitat

loss; cowbird control is the primary

recovery need, not habitat protection;

cowbird trapping would eliminate the

need for designating critical habitat; the

Service should implement and fund

cowbird control programs instead of

listing.

Service Response: The Service has

determined that cowbird parasitism is

one of several primary threats to E. t.

extimus, which also includes the loss

and modification of habitat. Cowbird

parasitism and loss and modification of

habitat are interrelated. Cowbird

parasitism is a function not just of

cowbird abundance, but also habitat

quality. Potential host species in

degraded, fragmented habitat are more

susceptible to nest parasitism than those

nesting in larger tracts of dense,

contiguous habitat. Cowbird parasitism
10702 Federal Register / Vol. 60, No. 38 / Monday, February 27, 1995 / Rules and Regulations

will probably remain an imminent

threat until habitat rehabilitation is

accomplished. The Service

acknowledges that cowbird control

should be an immediate, high priority

recovery action. However, cowbird

control is a ‘‘stop-gap’’ action.

Rehabilitating riparian habitat to make

E. t. extimus and other riparian birds

less susceptible to cowbird parasitism

will be necessary for a long-term

solution. Ultimately, the ranking of

threats in order of severity is not

relevant to the listing question. It is

because a number of often

interdependent threats exist that listing

E. t. extimus is necessary. Ranking

threats in order of severity and

addressing them accordingly will be

part of the recovery process.

Issue 16: Willow flycatchers nesting

in the northern States, Alaska, and

Canada are subspecies other than E. t.

extimus. The boundaries of the breeding

range of E. t. extimus should be

expanded to include the Santa Ynez

River in California, and the Green and

Colorado River systems in west-central

Utah; E. t. extimus does not occur in

Utah, Colorado, or the Carson National

Forest in northern New Mexico; the

willow flycatcher is common in the

northern States, Alaska, Canada, most of

the U.S., Mexico and Panama; caution

should be exercised in defining range

limits of the subspecies, including

elevational limits.

Service Response: Two primary

authorities (Unitt 1987, Browning 1993)

provide the range limits of E. t. extimus

identified in this rule (see Figure 1). The

Service also considered other

information, such as historical nesting

records, habitat characteristics, and

proximity to neighboring populations of

E. t. extimus or other willow flycatcher

subspecies. Using this information, the

Service provisionally defines the

northwestern limit of the subspecies’

range to be the Santa Ynez River in

California. Willow flycatchers nesting

along the Santa Ynez River occupy

lowland riparian habitat similar to other

coastal California locations of E. t.

extimus, and few willow flycatcher (i.e.,

E. t. brewsteri) nesting locales are

known in coastal California for a

considerable distance north of the Santa

Ynez River.

Browning (1993) found no evidence of

intergrades between E. t. extimus and E.

t. adastus in Utah. The northern limit of

E. t. extimus in Utah is believed to

correspond closely to the area

comprising the following counties:

Garfield, Kane, San Juan, Washington,

and Wayne. This area takes in stretches

of riverine riparian habitat in southern

Utah that have historical records of

flycatchers and that still have potential

willow flycatcher habitat.

The Service recognizes that

taxonomic questions may arise

concerning flycatchers occupying some

high-elevation locales within the range

of E. t. extimus. Because the genetic

relatedness of willow flycatchers

breeding at some high elevation areas,

such as the White Mountains of

Arizona, may be substantial, willow

flycatchers in those locales should be

considered E. t. extimus until further

research demonstrates otherwise.

Protection of these breeding groups

could be critical for population

recovery, immigration, and exchange of

genetic material within a highlyfragmented landscape.

Issue 17: It is inappropriate to use

data from E. t. brewsteri and E. t.

adastus to support listing E. t. extimus;

information cited on livestock damaging

nests comes from other subspecies.

Service Response: The Service

carefully considered the propriety of

using information on other willow

flycatcher subspecies in evaluating the

listing question for E. t. extimus. In

applying such information, the Service

considered ecological similarities and

dissimilarities between the subspecies.

The Service believes that data from

other subspecies are applicable in some

cases, but not others. The Service has

identified which subspecies provided

data sources throughout the proposed

and final rules. The phenomenon of

livestock damaging nests and/or

contents through physical contact is

known for willow flycatcher subspecies

other than E. t. extimus. This threat was

noted to recognize that the potential

exists, where nests occur low enough in

vegetation or in other vulnerable

locations, that livestock, humans, or

other animals may contact them or the

nest plant.

Issue 18: Habitat in California was lost

to urbanization, not livestock; the

proposed rule had inadequate

discussion of urban and suburban

development as a threat; urban

development is not a threat to some

populations.

Service Response: Loss and

modification of the riparian habitat of E.

t. extimus is the result of numerous

factors, discussed in depth in this rule.

Not all these factors have affected all

riparian habitats, and some rare habitats

remain unaffected. Further, the degree

to which these factors influence riparian

habitat varies across the landscape.

Urban and suburban development has

certainly impacted some E. t. extimus

habitats. These impacts may result from

direct encroachment and channelization

of riparian habitats, as in coastal

southern California and central Arizona.

Urban and suburban development also

increase demands on river systems for

water and hydropower. Thus,

expanding urban centers can result in

dewatering or alteration of riparian

systems tens or hundreds of miles away.

For example, the water and power

demands of Los Angeles, Phoenix and

Las Vegas result in effects on the

Colorado River hundreds of miles from

any of these cities.

Issue 19: The primary threat to E. t.

extimus is loss of wintering habitat in

Central and South America, or other

factors along migration routes; the

proposed rule contained insufficient

information on migration studies;

protecting breeding grounds is not

logical, because E. t. extimus spends

eight months of the year in migration or

on wintering grounds.

Service Response: Although tropical

deforestation possibly may restrict

wintering habitat of the willow

flycatcher, the best available current

information on the subject suggests

otherwise. The limited data on willow

flycatcher wintering habitat indicates

that this species uses ‘‘* * * brushy

savannah edges and second growth’’ in

Costa Rica (Stiles and Skutch 1989); in

Panama it has been documented in

‘‘shrubby areas’’ (Ridgely 1981); and in

South America it has been documented

in ‘‘* * * shrubby clearings, pastures,

and lighter woodland’’ or ‘‘* * * on

islands with early successional growth’’

(Ridgely and Tudor 1994). Given

existing land use practices in Central

and South America, which are

characterized by conversion of oldgrowth forested habitat to agricultural

and second-growth habitats, few if any

of the winter habitat types in which

willow flycatchers have been

documented should currently be in

jeopardy.

Issue 20: The Service cannot define

nesting habitat; habitat requirements are

poorly understood; the proposed rule’s

description of nesting habitat is flawed

and inadequate to direct management;

the minimum patch size necessary to

support a nesting pair of E. t. extimus

is 1 to 1.5 hectares.

Service Response: The Service

believes the proposed rule and this final

rule accurately compile and summarize

the existing information on E. t. extimus

nesting habitat, and that information is

sufficient to identify, conserve, and

recover the riparian ecosystem of which

E. t. extimus is a part. Habitat patches

occupied by E. t. extimus vary

somewhat in size, floristic composition,

vegetation structure, and type of

wetland. Therefore, the Service believes

it is inappropriate and inaccurate to
Federal Register / Vol. 60, No. 38 / Monday, February 27, 1995 / Rules and Regulations 10703

narrowly define suitable habitat in

terms of plants per unit area, vegetation

density, specific plant community

composition, type and volume of

surface water, and patch size. The

Service has no information to indicate

inaccuracy or inadequacy of the habitat

description presented in this rule.

Specifically regarding patch sizes, one

to two E. t. extimus pairs have been

observed nesting in habitat patches of

0.5 ha (Sogge et al. 1993, Sogge et al.

unpubl. 1994 data); therefore 1.0 to 1.5

ha is not an accurate estimate of the

minimum patch size needed to support

a single nesting pair.

Issue 21: Habitats used by nesting

pairs differ from those used by single,

unmated, wandering, or migrant

flycatchers; the latter face minimal

threats and are not essential to

conservation of the species.

Service Response: The commenters

provided no data supporting the

statement that habitats used by unpaired

E. t. extimus differ from nesting habitat,

and the Service found no indication of

this in the available literature. Unmated,

resident E. t. extimus have been found

in habitats identical to nearby habitats

occupied by nesting pairs (Sogge and

Tibbitts 1992, Sogge et al. 1993). The

Service believes that single, unmated E.

t. extimus also face threats of habitat

loss, and that conservation of these

individuals is essential to the

conservation of the species, particularly

at the low current numbers of

flycatchers.

Issue 22: Listing constitutes singlespecies management that will damage

other species; E. t. extimus habitat is

incompatible with habitat needs of other

listed and sensitive species, particularly

the spikedace and loach minnow.

Service Response: The purposes of the

Act are to provide a program for the

conservation of threatened and

endangered species and to conserve the

ecosystems upon which threatened and

endangered species depend. The Service

believes that managing for E. t. extimus

and other listed riparian and aquatic

species accomplishes this purpose, to

the mutual benefit of listed and

nonlisted species alike. The intent of

this listing is to conserve and recover E.

t. extimus and the riparian and aquatic

ecosystems of which it is a part.

The primary constituent elements of

critical habitat described for the

spikedace (59 FR 10906) and loach

minnow (59 FR 10898) are not in

conflict with the habitat requirements

for the southwestern willow flycatcher,

and are not in conflict with the primary

constituent elements of its proposed

critical habitat (58 FR 39495). The fishes

require ‘‘a healthy, intact riparian

community,’’ which will also benefit E.

t. extimus and other riparian and

aquatic species. The spikedace, loach

minnow, and E. t. extimus all require

surface water and/or a high water table,

a low to moderate stream gradient, and

periodic flooding. The fishes

specifically require a ‘‘natural,

unregulated hydrograph,’’ which the

Service believes would also benefit the

flycatcher. These fish also require

moderate to high bank stability;

maintenance of the riparian vegetation

on which E. t. extimus depends will

provide such bank stability. The Service

does not view management for E. t.

extimus, spikedace, and loach minnow

as mutually exclusive, but as mutually

beneficial.

Issue 23: Floods regenerate habitat,

they do not destroy it; floods destroy

habitat; floods, not livestock, caused

much of riparian degradation; the

proposed rule is confusing and

contradictory on the role of floods as a

threat or necessary ecological function.

Service Response: The proposed rule

stated that ‘‘Its habitat rarity, and small,

isolated populations make the

remaining E. t. extimus increasingly

susceptible to local extirpation through

stochastic events such as floods * * *.

In early 1993, catastrophic floods in

southern California and Arizona

damaged or destroyed much of the

remaining occupied or potential

breeding habitat. Historically, these

floods have always destroyed habitat

but were also important events in

regenerating cottonwood-willow

communities.’’

It is important to note that E. t.

extimus is threatened by stochastic

events like floods because of its current

rarity and isolated nature of

populations. If the species existed at

healthy population levels, and if its

riparian habitat were not greatly

reduced, these natural stochastic events

would not constitute threats. The 1993

flood events referred to were

extraordinary in nature, described

regionally as 500-year floods. Therefore,

they do not typify flood events in the

river systems involved. Further, while

natural flood events are expected to

destroy some flycatcher habitat, they are

also crucial for regenerating natural

riparian nesting habitat. In a healthy

system where riparian vegetation is

abundant and the stream channel is not

eroded or destabilized, destruction and

regeneration are balanced and habitat is

generally available. Only when riparian

vegetation is severely reduced and the

stream channel and watershed are

destabilized are riparian and aquatic

species threatened by the natural, shortterm habitat losses resulting from

flooding.

Issue 24: To manage for E. t. extimus,

the Service will enforce or has proposed

a fenced livestock-free corridor.

Service Response: The Service has

neither proposed nor been consulted

regarding a fenced, livestock-free

corridor established along riparian areas

on State, Federal, or private lands.

Issue 25: Beneficial land management

practices should be recognized and

discussed; the proposed rule fails to

acknowledge that some habitats are

protected from urban development.

Service Response: The Service

recognizes that some management

practices are beneficial. Some practices

have protected or improved habitat,

resulted in expanded populations, and/

or improved reproduction. The Service

will look to these beneficial land

management practices as important

examples in the recovery planning

process. However, in making a listing

determination the Service must consider

the situation across the species’ entire

range. It is this overall perspective that

drives the listing decision. Although

some nesting groups of E. t. extimus

may be safe, stable, or perhaps even

increasing, the Service has determined

that overall the species is endangered.

Issue 26: Existing regulatory

mechanisms are adequate, including:

the Migratory Bird Treaty Act (MBTA);

State listings for Arizona, New Mexico,

and California; section 404 of the Clean

Water Act; Bureau of Land Management

and Forest Service policies; Executive

Orders 11988 and 11990; protection of

riparian habitat due to presence of other

listed species; private and/or

cooperative management plans at local

areas.

Service Response: The Service

considered these regulatory mechanisms

and management plans, and determines

that overall existing regulatory

mechanisms are insufficient to conserve

and recover E. t. extimus in the face of

the primary threats of loss and

modification of habitat and cowbird

parasitism. A full discussion of Federal

and State protection is found in this

document under Factor D: ‘‘Inadequacy

of existing regulatory mechanisms’’.

The Service recognizes that some

local management plans benefit and

conserve E. t. extimus and its habitat.

Examples include management of the

Bureau of Land Management’s San

Pedro Riparian National Conservation

Area (SPRNCA) in Arizona, where six

years of livestock exclusion have

resulted in significant restoration of

riparian habitats and increases in birds

associated with habitats similar to E. t.

extimus (Krueper 1993). Willow
10704 Federal Register / Vol. 60, No. 38 / Monday, February 27, 1995 / Rules and Regulations

flycatchers have not yet returned to

their historical locations on the

SPRNCA but may soon. Habitat

protection and cowbird management at

The Nature Conservancy’s Kern River

Preserve and on Marine Corps Base

Camp Pendleton in California have

improved habitat and reduced brood

parasitism pressures for resident E. t.

extimus (Griffith and Griffith 1993).

Wetland management at Bosque del

Apache National Wildlife Refuge in

New Mexico is apparently sustaining a

small population of flycatchers. While

these actions are beneficial, they

provide for E. t. extimus only at several

locales. Further, long-term continuation

of these management actions is not

assured.

Provisions of section 404 of the Clean

Water Act do not specifically protect E.

t. extimus or its habitat, but do provide

some protection to the aquatic and

riparian ecosystems of which it is a part.

Section 404 of the Clean Water Act also

provides for mitigation of destruction of

these habitats, however, allowing even

temporary destruction of riparian

habitat is not consistent with the

immediate conservation needs of E. t.

extimus.

Issue 27: The Service did not use the

best available scientific or commercial

information in making this

determination; the Service presented

insufficient and inconclusive

information to support listing; the

proposed rule used information which

was general, incomplete, and originated

with other flycatcher subspecies; the

proposed rule was premature; the

Service did not adequately solicit

information and public input; scientific,

economic, biological, hydrological and

botanical data must support listing; how

does the Service know the scientific

information supporting listing was

right?

Service Response: The Service

canvassed the published literature

regarding the taxonomy, ecology, and

biology of the southwestern willow

flycatcher, and the threats to it and its

habitat. Because numerous and complex

phenomena and processes were

involved, this information ranged from

general (e.g., wide scale trends in

riparian habitat) to very specific (status

of nesting groups). The Service believes

it used the best available information,

and has determined that this

information is adequate to support

listing. The Service evaluates sources

before using or discounting information.

In general, the Service expects that

publications in peer-reviewed scientific

journals, reports from land and resource

management agencies, and dissertations

or reports from academic or research

institutions have undergone technical

review. Other information sources are

considered more anecdotal, and the

Service seeks to confirm such

information before using it.

Issue 28: The Service should comply

with the National Environmental Policy

Act (NEPA) by completing an

Environmental Impact Statement (EIS),

and comply with 40 CFR 1506 to reduce

duplication between NEPA and State

and local requirements; the Service

should comply with 40 CFR 1508.20 to

compensate for producing substitute

resources or environments; the Service

should engage in joint planning with

local governments under NEPA

regulations.

Service Response: As noted in this

final rule, the Service has determined

that an Environmental Assessment, as

defined under the authority of NEPA,

need not be prepared for listing actions.

A notice outlining the Service’s reasons

for this determination was published in

the Federal Register on October 25,

1983 (48 FR 49244). Because of this

determination, an EIS also need not be

prepared. Also because of this

determination, reduction of duplication

between the NEPA process and State

and local agencies, and joint planning

between those agencies and the NEPA

process, are rendered moot.

Issue 29: The proposed rule violates

the Regulatory Flexibility Act; no

Regulatory Impact Analysis/Assessment

as required under Executive Orders

12291 and 12866 was completed; it also

may be inconsistent with the mandates

of other agencies.

Service Response: Decisions on listing

and reclassification under the Act are

made based on five factors defined in

section 4(a)(1) of the Act. These five

factors are discussed in this rule, as they

relate to E. t. extimus. The Act requires

the Service to consider only scientific

and commercial information relating to

these five factors in making listing

determinations, not economic

information. Economic information is

considered in designating critical

habitat, which is not part of this rule.

Therefore, compliance with the

Regulatory Flexibility Act and Executive

Orders 12291 and 12866 is not an issue

for this action, but will be addressed if

a critical habitat designation is made

(H.R. Conf. Rep. No. 835, 97th Cong., 2d

Sess. 20 (1982); accord, S. Rep. No. 418,

97th Cong., 2d Sess. 4 (1982)).

Where conservation and recovery of

threatened and endangered species is

inconsistent with other mandates of

Federal agencies, processes under

section 7 of the Act serve to evaluate

projects arising from those mandates,

with regard to protection of listed

species. However, section 2(c) of the Act

requires all Federal departments and

agencies to conserve listed species and

further the purposes of the Act.

Issue 30: The Service should complete

a Takings Implications Assessment prior

to listing/designating critical habitat.

Service Response: The Service will

complete a takings analysis for any final

designation of critical habitat in

compliance with Executive Order 12630

and the Attorney General’s

supplemental guidelines issued June 30,

1988. In accordance with those

guidelines and Interior Department

policy, this analysis will be completed

after listing, not as part of consideration

of the listing determination itself.

Issue 31: Requests were received for

local public hearings.

Service Response: The proposed rule

stated that three public hearings would

be held. Because of many requests for

additional hearings, a total of six public

hearings were held. Regulations at 50

CFR 424.16(c)(3) require the Service to

hold one public hearing if requested.

Issue 32: The time allowed for public

comments was inadequate; the proposal

should have been subjected to peer

review.

Service Response: The Service is

required to accept public comments for

at least 60 days regarding proposals to

list and/or designate critical habitat (50

CFR 424.16(c)(2)). In this case the

Service initially announced a 90-day

public comment period, then extended

that another 40 days for a total of 130

days (July 23, 1993 through November

30, 1993). Public comment periods and

public hearings are the mechanisms by

which the Service receives input from

all interested parties, including

scientific peer review.

Issue 33: Listing would require

private property owners to consult with

the Service on their actions; listing and/

or designating critical habitat constitute

take of private property rights; adverse

modification of critical habitat would be

prohibited on private lands; the Service

failed to notify the affected public of the

consequences of adverse modification of

critical habitat; listing and/or

designating critical habitat may affect

civil rights.

Service Response: Listing does not

require private property owners to

consult with the Service on actions

which may affect a listed species.

However, section 7 of the Act does

require Federal agencies to consult on

actions which they fund, permit, or

carry out if those actions may affect a

listed species or adversely modify

critical habitat. Any potential take of

private property will be analyzed in

compliance with Executive Order 12630
Federal Register / Vol. 60, No. 38 / Monday, February 27, 1995 / Rules and Regulations 10705

(see Issue 30). As discussed later (Issue

35), because critical habitat is not being

designated with this rule, comments

regarding critical habitat will be

addressed during subsequent actions

regarding critical habitat.

Issue 34: Requests were received to be

on a mailing list for all actions relating

to this issue or to be provided personal

notification of a final decision.

Service Response: The Service tries to

maintain mailing lists for specific issues

whenever possible. However, when

large numbers of parties request to be on

such lists, it becomes logistically and

financially unfeasible to mail

information to each party. This issue is

one of those, and the Service must rely

to some degree on mass communication

forums like news releases, public

notices in newspapers, and publications

in the Federal Register.

Issue 35: Numerous comments were

received regarding critical habitat.

Service Response: Critical habitat for

E. t. extimus is not being designated

with this rule; therefore, the above

issues are not addressed here.

Designation of critical habitat is being

deferred while the Service further

considers the extent to which

designation is appropriate. Issues

pertaining to this designation will be

addressed when a final decision is made

with regard to the critical habitat

proposal.

Issue 36: Numerous comments were

received regarding recovery of E. t.

extimus, including: the Service has no

recovery plan for E. t. extimus; the

proposed rule failed to identify recovery

goals for habitat, flycatcher numbers,

and flycatcher distribution; the

proposed rule failed to identify what

actions will be used to achieve recovery;

a recovery plan should address control

of cowbird parasitism, nest damage by

livestock, tamarisk eradication,

wintering habitat, monitoring

populations, protection of public and

private lands from fire; cowbird

parasitism cannot be addressed by

listing and designating critical habitat;

cowbirds are not easily controlled

without sacrificing flycatchers and/or

impacting habitat; the proposed rule

contained no livestock managing

strategy; rotating livestock will allow

habitat enhancement/recovery; the

factors affecting riparian habitats are

numerous and complex; failure to

address all could be futile or have

damaging effects.

Service Response: Section 4(f) of the

Act authorizes the Service to develop

and implement recovery plans for listed

species, not species that are proposed

for listing. For E. t. extimus, this process

therefore begins with the effective date

of listing. In accordance with section

4(f)(B) of the Act the recovery plan

process will address actions necessary

to achieve conservation and recovery of

E. t. extimus, will identify measurable

criteria by which recovery (i.e., the

point at which protection under the Act

is no longer necessary) can be gauged,

and will identify the time and costs

required to achieve recovery. The

specific issues identified above will be

considered in developing a recovery

plan, and that plan will be available for

public review and comment prior to

adoption. Monitoring species is

frequently an element of recovery plans,

and is also required by section 4(g) of

the Act for any species deemed to be

recovered.

Issue 37: Several commenters

questioned the motivations of the

petitioners in requesting the listing, and

others apparently believed the

petitioners authored the listing

proposal. Several commenters noted

that the petition contained inaccuracies,

and therefore no listing proposal should

have resulted.

Service Response: The Service cannot

speak for the petitioners’ motivations in

requesting listing of E. t. extimus. The

Service judged the petition solely on the

scientific information it contained.

Inaccuracies were found in the petition,

but on the whole the Service

determined that it presented substantial

information indicating that listing may

be warranted. The listing proposal was

authored by the Service, not the

petitioners. The Service developed its

proposal not from the petition, but from

information gained from journal

publications, agency reports, and the

general public’s responses to several

information solicitations. This status

review process had resulted in the

Service designating E. t. extimus a

category 1 candidate species prior to the

petition being received. That

designation indicated that the Service

had sufficient information to support a

listing proposal but did not publish a

proposal immediately because it was

dealing with listing actions of higher

priority. Information presented by the

petitioners that the Service did not

already possess was checked for

accuracy; information that could not be

confirmed, or was found to be

inaccurate, was not used.

Issue 38: The Service is required to

purchase interest in land or water for

implementation of the Act; this violates

the U.S. Constitution.

Service Response: Section 5 of the Act

directs the Secretary to use land

acquisition and other authorities of the

Fish and Wildlife Act of 1956, as

amended, the Fish and Wildlife

Coordination Act, as amended, and the

Migratory Bird Conservation Act, as

appropriate. The Secretary is

authorized, but not required, to acquire

interest in land or water to conserve

threatened and endangered species. The

Service does not carry out these

authorities in violation of the U.S.

Constitution. The Service does not

acquire all lands designated as critical

habitat for a listed species, and does not

develop critical habitat designations

based on land ownership or interest of

landowners in purchasing or selling

properties. It is the Service’s policy to

acquire property only on a voluntary

basis from willing sellers.

Issue 39: Land use outside occupied/

critical habitat will be adversely

impacted.

Service Response: Federal actions that

take place outside occupied habitat or

critical habitat, but that may affect E. t.

extimus, will be subject to consultation

between the action agency and the

Service in accordance with section 7 of

the Act. Exclusively private actions are

unaffected by listing and/or designation

of critical habitat, provided they do not

result in violation of section 9 of the Act

(e.g., take of the species).

Issue 40: Listing (regardless of critical

habitat) will have adverse impacts on

local economy; economic impacts of

listing were not addressed; the Act

requires the Service to consider impacts

on other wildlife species and social and

economic impacts prior to listing.

Service Response: Consideration of

economic effects is required for

designation of critical habitat. The Act

requires that species listing decisions be

based solely on the best scientific and

commercial information available,

which precludes consideration of social

or cultural impacts or impacts on other

species. (See section 4(b)(1)(A) of the

Act). The Service anticipates no

significant impacts on other native

wildlife species as a result of listing,

with the probable exception of the

brown-headed cowbird.

Issue 41: Who initiated, performed,

and paid for studies along the Kern

River?

Service Response: Reports on studies

done on the Kern River were published

by Harris et al. (1986), Harris et al.

(1987), Whitfield (1990), and Harris

(1991). Specific information on project

participants, funding sources, and

cooperators can be found in those

sources. The Service understands that

monitoring and cowbird control are

being continued by the Kern River

Research Center and The Nature

Conservancy, with funding assistance

from the State of California and the

Service.
10706 Federal Register / Vol. 60, No. 38 / Monday, February 27, 1995 / Rules and Regulations

Issue 42: The Service should perform

additional surveys before listing.

Service Response: The Service is

supporting continuing surveys to detect

additional E. t. extimus, to monitor

known nest sites, and to evaluate habitat

presence, quality, and distribution. The

Service supports these surveys with

funding to States in accordance with

section 6 of the Act, and through

logistical and technical assistance to

other agencies and parties. Extensive

surveys in New Mexico and Arizona in

1993 located E. t. extimus in numbers

that do not significantly change the total

population estimates made in the

proposed rule. These surveys also

confirmed high levels of brood

parasitism by cowbirds. With low

estimates of total flycatcher numbers

being validated by continuing surveys,

the Service has determined that

sufficient information exists on the

threats of habitat loss and cowbird

parasitism to justify listing.

Issue 43: The Service failed to consult

adequately with private interests, State,

Federal, and local agencies prior to

publishing the proposed rule.

Service Response: The Service

published public requests for

information on the status of E. t. extimus

in the Federal Register when it was

designated a category 2 candidate

species in January 1989, and when it

was designated a category 1 species in

November 1991. The Service

supplemented these requests with

general mailings soliciting information,

and information solicitations in

professional publications. Beyond these

mechanisms, the Service is constrained

by funding limitations and citizens’

suits such as Environmental Defense

Center, Inc. vs. Babbitt et al. IV 93–

1848–R (C.D. Calif.), which was brought

to compel the Service to propose listing

and designation of critical habitat for

the species, that preclude individually

contacting every interested party.

Issue 44: The parties who petitioned

for listing should pay for studies

supporting their request.

Service Response: Regulations

implementing section 4 of the Act,

specifically the petition process [50 CFR

424.14], do not require petitioners to

fund studies supporting their request.

Listing determinations are made if

existing information is deemed

sufficient to make a determination. This

information typically originates from a

variety of sources.

Issue 45: The southwestern willow

flycatcher is abundant. There is no need

to list.

Service Response: The Service has

determined that E. t. extimus is rare, not

abundant, faces serious threats to its

continued existence, and warrants

listing as endangered. See discussion

under Factor A: The present or

threatened destruction, modification, or

curtailment of its habitat or range.

Issue 46: The ‘‘little’’ willow

flycatcher (E. t. brewsteri) is the most

common subspecies observed and

collected in the Southwest.

Service Response: The abundance of

collections of E. t. brewsteri from within

the breeding range of E. t. extimus is

because E. t. brewsteri migrates through

the Southwest between its Pacific

coastal breeding range and wintering

grounds in Central America. E. t.

brewsteri passes through riparian

habitats in the breeding range of E. t.

extimus in spring and fall, but does not

breed there.

Issue 47: There is no need to list E.

t. extimus in areas where it is doing

well.

Service Response: The Service has

determined that E. t. extimus is

endangered; local areas where the bird

is relatively stable could only be

excluded from listing or classified as

threatened if they constituted distinct

population segments [50 CFR 424.02(k)].

The Service has not identified any

distinct population segments of E. t.

extimus. Further, because the Service

determines E. t. extimus to be

endangered, all existing habitat and

local nesting concentrations are deemed

to be essential to the conservation and

recovery of the species. Protection of

locales where the bird is doing

relatively well may be especially

important for the conservation and

recovery of E. t. extimus.

Issue 48: Prey availability may be a

limiting factor.

Service Response: The Service

recognizes that food availability is

always a potential limiting factor in

wildlife populations. It is possible that

reduction of riparian habitats not only

reduced vegetation for nesting, but

reduced or altered the arthropod fauna

associated with surface water and

extensive vegetation. Also, as noted in

this rule, some speculation exists that

tamarisk provides a substandard nesting

habitat because it supports a

significantly different insect fauna than

native vegetation. However, no

information was available to evaluate

this factor directly for E. t. extimus.

Issue 49: Several comments were

received that pertained to the Service’s

management of the 90-day petition

finding, including that the 90-day

petition finding was late; that it is not

the Service’s role to conduct a status

review if information in a petition is

lacking; and that a 30-day comment

period on the 90-day petition finding

was insufficient.

Service Response: The Service

acknowledges that its finding on the

listing petition was published after 90

days, however, the Act (section

4(b)(3)(A) states that the [Service] shall,

to the maximum extent practicable,

make a petition finding within 90 days

(emphasis added). Because the petition

was found to present substantial

information indicating that the

petitioned action may have been

warranted, the Service continued a

status review after this finding, in

accordance with 50 CFR 424.14(b)(3).

There are no requirements for the

Service to open a formal comment

period regarding a 90-day petition

finding. The Service did so in this case

to solicit additional information on E. t.

extimus. In reaching its 12-month

petition finding, the Service considered

all information received within the 30-

day period identified, and information

received for several months thereafter.

Issue 50: E. t. extimus should be listed

as threatened, not endangered.

Service Response: The Service

carefully evaluated the status of E. t.

extimus and has determined that it

meets the definition of an endangered

species, not a threatened species. As

stated in the proposed rule, (58 FR

39495) threatened status would not be

appropriate because the large historic

habitat loss already has caused

extirpation throughout a significant

portion of the species’ range. Population

numbers are extremely low, and a

variety of threats are serious and

imminent.

Issue 51: Restrictions on rural

livestock grazing will cause ranching to

become nonviable, and the land will be

converted by suburban development,

which is a greater threat to E. t. extimus

than overgrazing.

Service Response: The conversion of

lands from livestock grazing to suburban

development is hypothetical and

therefore cannot drive the Service’s

determination on this issue. Much of the

livestock grazing that may be affected by

this rule takes place on Federal lands.

Therefore, conversion to suburban

development would require land

exchanges or sales. These actions, if

they were determined to affect E. t.

extimus, would require consultation

under section 7 of the Act. Regardless,

prioritization of threats should be

undertaken in the recovery, rather than

listing, process.

Issue 52: The proposed rule fails to

consider changing ecological factors:

drought, migration patterns, nesting

habits, and climatic changes.
Federal Register / Vol. 60, No. 38 / Monday, February 27, 1995 / Rules and Regulations 10707

Service Response: The Service

recognizes that populations of E. t.

extimus are likely to fluctuate naturally

in response to various ecological factors.

However, the Service believes that

declines in habitat availability and

increased exposure to cowbird

parasitism have caused population

reductions beyond the scale of natural

fluctuations. Fluctuations in response to

nonanthropogenic phenomena are likely

to continue, but the current population

levels are so low that these natural

phenomena may be sufficient to cause

local extirpations.

Issue 53: Restrictions associated with

listing would be in conflict with Kern

County’s General Plan.

Service Response: Under section 4 of

the Act, the Service considers only

scientific and commercial information

relating to the five listing factors

outlined in section 4(a)(1) and discussed

with respect to E. t. extimus in this rule.

Therefore, conflicts with local plans

were not considered in making this

determination. However, the Service

strives to pursue conservation and

recovery of listed species in cooperation

with State and local authorities, and

seeks to minimize conflicts.

Issue 54: Listing and critical habitat

designations will adversely affect flood

control measures, some authorized by

the Federal Emergency Management

Agency and other Federal and State

regulations; the proposed rule failed to

consider flood accommodation needs,

channelization, and clearing vegetation.

Service Response: Flood control

measures virtually always involve a

Federal agency, through funding,

permitting, and/or other action.

Therefore, flood control measures that

may affect E. t. extimus would undergo

consultation under section 7 of the Act.

Section 7 and its implementing

regulations have provisions for

emergency consultations, and for

actions within presidentially declared

disaster areas.

Issue 55: Government agencies are

responsible for many impacts to riparian

areas; campgrounds, fish hatcheries, and

some district offices are located in

riparian areas.

Service Response: The Service

acknowledges that some Federal actions

are in part responsible for the threats

facing E. t. extimus. As a result of

listing, those Federal actions will be

subject to consultation under section 7

of the Act to evaluate and minimize the

effects of those actions.

Issue 56: The Service does not

acknowledge receipt of comments on

listing, and probably does not read

them.

Service Response: The Service does

not routinely acknowledge receipt of

each letter commenting on listing

proposals. The number of letters in this

case made it logistically and financially

impossible to acknowledge each one.

However, all letters were read, and their

issues addressed either here or

elsewhere in this final rule. All

comment letters and transcripts of

public hearings are retained in the

permanent file on this species and are

available for public inspection.

Issue 57: Protecting flycatcher habitat

may restrict mosquito control, which is

important for control of encephalitis

and other mosquito-borne diseases.

Service Response: Where such control

involves a Federal action, mosquito and

disease control actions may be subject to

consultation under section 7(a)(2) of the

Act, which would evaluate but not

necessarily restrict or significantly

modify the project. Ultimately, section

7(e) of the Act allows exemptions to the

requirements of section 7(a)(2).

Summary of Factors Affecting the

Species

After a thorough review and

consideration of all information

available, the Service has determined

that the southwestern willow flycatcher

should be classified as an endangered

species. Procedures found at section

4(a)(1) of the Act and regulations

implementing the listing provisions of

the Act (50 CFR Part 424) were

followed. A species may be determined

to be an endangered or threatened

species due to one or more of the five

factors described in section 4(a)(1).

These factors and their application to

the southwestern willow flycatcher

(Empidonax traillii extimus) are as

follows:

A. The Present or Threatened

Destruction, Modification, or

Curtailment of its Habitat or Range

Large scale losses of southwestern

wetlands have occurred, particularly the

cottonwood-willow riparian habitats of

the southwestern willow flycatcher

(Phillips et al. 1964, Carothers 1977, Rea

1983, Johnson and Haight 1984, Katibah

1984, Johnson et al. 1987, Unitt 1987,

General Accounting Office (GAO) 1988,

Bowler 1989, Szaro 1989, Dahl 1990,

State of Arizona 1990, Howe and Knopf

1991). Changes in riparian plant

communities have resulted in the

reduction, degradation, and elimination

of nesting habitat for the willow

flycatcher, curtailing the ranges,

distributions, and numbers of western

subspecies, including E. t. extimus

(Gaines 1974, Serena 1982, Cannon and

Knopf 1984, Klebenow and Oakleaf

1984, Taylor 1986, Unitt 1987, Schlorff

1990, Ehrlich et al. 1992).

Dahl (1990) reviewed estimated losses

of wetlands between 1780 and the

1980’s in the Southwest: California is

estimated to have lost 91 percent,

Nevada 52 percent, Utah 30 percent,

Arizona 36 percent, New Mexico 33

percent, and Texas 52 percent. As much

as 90 percent of major lowland riparian

habitat has been lost or modified in

Arizona (State of Arizona 1990).

Franzreb (1987) noted that

‘‘[B]ottomland riparian forests are the

most highly modified of natural

landscapes in California.’’

Loss and modification of

southwestern riparian habitats have

occurred from urban and agricultural

development, water diversion and

impoundment, channelization, livestock

grazing, off-road vehicle and other

recreational uses, and hydrological

changes resulting from these and other

land uses. Rosenberg et al. (1991) noted

that ‘‘it is the cottonwood-willow plant

community that has declined most with

modern river management.’’ Loss of the

cottonwood-willow riparian forests has

had widespread impact on the

distribution and abundance of bird

species associated with that forest type

(Hunter et al. 1987, Hunter et al. 1988,

Rosenberg et al. 1991).

Overuse by livestock has been a major

factor in the degradation and

modification of riparian habitats in the

western United States. These effects

include changes in plant community

structure and species composition, and

relative abundance of species and plant

density. These changes are often linked

to more widespread changes in

watershed hydrology (Rea 1983, General

Accounting Office 1988) and directly

affect the habitat characteristics critical

to E. t. extimus. Livestock grazing in

riparian habitats typically results in

reduction of plant species diversity and

density, especially of palatable

broadleaf plants like willows and

cottonwood saplings, and is one of the

most common causes of riparian

degradation (Carothers 1977, USDA

Forest Service 1979, Rickard and

Cushing 1982, Cannon and Knopf 1984,

Klebenow and Oakleaf 1984, GAO 1988,

Clary and Webster 1989, Schultz and

Leininger 1990).

Increases in abundance of riparian

bird species have followed reduction,

modification, or removal of cattle

grazing. Krueper (1993) found the

following increases in birds associated

with cottonwood-willow habitat on

Arizona’s San Pedro River four years

after the removal of livestock: yellow

warbler, 606 percent; common yellowthroat, 2,128 percent; yellow-breasted
10708 Federal Register / Vol. 60, No. 38 / Monday, February 27, 1995 / Rules and Regulations

chat, 423 percent. Bock et al. (1993)

found that 40 percent of the riparian

bird species they examined, including

the willow flycatcher (various

subspecies), were negatively affected by

livestock grazing. Increases in willow

flycatcher numbers (various subspecies)

have followed reduction, modification,

or removal of cattle grazing. Taylor

(1986) found a negative correlation

between recent cattle grazing and

abundance of numerous riparian birds,

including the Great Basin willow

flycatcher (E. t. adastus). In an area

ungrazed since 1940, his bird counts

were five to seven times higher than

comparable plots where grazing was

terminated in 1980. Taylor and

Littlefield (1986) found higher numbers

of Great Basin willow flycatchers

correlated with minimal or nonexistent

livestock grazing. Klebenow and Oakleaf

(1984) listed the Great Basin willow

flycatcher among bird species that

declined from abundant to absent in

riparian habitats degraded in part by

overgrazing. Schlorff reported willow

flycatchers returning to Modoc County,

California, several years after removal of

livestock grazing (pers. comm. cited in

Valentine et al. 1988). Knopf et al.

(1988) found that, during the summer,

Great Basin willow flycatchers were

present on winter-grazed pastures, but

were virtually absent from summergrazed pastures.

The Service believes that

documentation of livestock impacts on

other willow flycatcher subspecies is

relevant to E. t. extimus, because linear

riparian habitats in the arid range of E.

t. extimus are especially vulnerable to

fragmentation and destruction by

livestock. As shady, cool, wet areas

providing abundant forage, they are

disproportionately preferred by

livestock over the surrounding xeric

uplands (Ames 1977, Valentine et al.

1988, A. Johnson 1989). Harris et al.

(1987) believed that termination of

grazing along portions of the South Fork

of the Kern River in California was

responsible for increases in riparian

vegetation and, consequently, nesting E.

t. extimus. Suckling et al. (1992) noted

that most of the areas still known to

support E. t. extimus have low or

nonexistent levels of livestock grazing.

More recent surveys (Muiznieks et al.

1994) have found E. t. extimus in areas

with livestock grazing; however, these

occur in widely dispersed, small groups

whose nesting success is largely

unknown, and where livestock grazing

intensity and seasonality are also

unknown.

Another likely factor in the loss and

modification of southwestern willow

flycatcher habitat is invasion by the

exotic tamarisk. Tamarisk (also called

saltcedar) was introduced into western

North America from the Middle East in

the late 1800’s as an ornamental

windbreak and for erosion control. It

has spread rapidly along southwestern

watercourses, typically at the expense of

native riparian vegetation, especially

cottonwood/willow communities.

Although tamarisk is present in nearly

every southwestern riparian

community, its dominance varies. It has

replaced some communities entirely,

but occurs at a low frequency in others.

The spread and persistence of

tamarisk has resulted in significant

changes in riparian plant communities.

In monotypic tamarisk stands, the most

striking change is the loss of community

structure. The multilayered community

of herbaceous understory, small shrubs,

middle-layer willows, and overstory

deciduous trees is often replaced by one

monotonous layer. Plant species

diversity has declined in many areas,

and relative species abundance has

shifted in others. Other effects include

changes in percent cover, total biomass,

fire cycles, thermal regimes, and

perhaps insect fauna (Kerpez and Smith

1987, Carothers and Brown 1991,

Rosenberg et al. 1991, Busch and Smith

1993).

Disturbance regimes imposed by man

(e.g., grazing, water diversion, flood

control, woodcutting, and vegetation

clearing) have facilitated the spread of

tamarisk (Behle and Higgins 1959,

Kerpez and Smith 1987, Hunter et al.

1988, Rosenberg et al. 1991). Cattle find

tamarisk unpalatable. However, they eat

the shoots and seedlings of cottonwood

and willow, acting as a selective agent

to shift the relative abundance of these

species (Kerpez and Smith 1987).

Degradation and, in some cases, loss of

native riparian vegetation lowered the

water table and resulted in the loss of

perennial flows in some streams. With

its deep root system and adaptive

reproductive strategy, tamarisk thrives

or persists where surface flow has been

reduced or lost. Further, tamarisk

establishment often results in a selfperpetuating regime of periodic fires,

which were uncommon in native

riparian woodlands (Busch and Smith

1993).

Manipulation of perennial rivers and

streams has resulted in habitats that

tend to allow tamarisk to outcompete

native vegetation. Construction of dams

created impoundments that destroyed

native riparian communities. Dams also

eliminated or changed flood regimes,

which were essential in maintaining

native riparian ecosystems. Changing

(usually eliminating) flood regimes

provided a competitive edge to

tamarisk. In contrast to native

phreatophytes, tamarisk does not need

floods and is intolerant of submersion

when young. Diversion of water caused

the lowering of near-surface

groundwater and reduced the relative

success of native species in becoming

established. Irrigation water containing

high levels of dissolved salts also favors

tamarisk, which is more tolerant of high

salt levels than most native species

(Kerpez and Smith 1987, Busch and

Smith 1993).

The rapid spread of tamarisk has

coincided with the decline of the

southwestern willow flycatcher.

Although E. t. extimus has been

documented nesting in tamarisk, it is

not known whether, over the long term,

reproductive success of southwestern

willow flycatchers nesting in tamarisk

has differed from the success of

flycatchers nesting in native vegetation.

Studies in Arizona have documented

low breeding densities and low

reproductive success for southwestern

willow flycatchers nesting in tamarisk

(Hunter et al. 1988, Muiznieks et al.

1994). These data, coupled with a

possible decrease in the arthropod prey

base and thermal protection for nests

provided by tamarisk, suggest that

tamarisk may provide poor quality

nesting habitat. However, more

extensive comparative studies are

needed to determine the overall impact

on the southwestern willow flycatcher

of the conversion of native broadleafdominated riparian habitat to tamariskdominated habitat.

Other studies of riparian bird

communities have documented changes

in bird species diversity, corresponding

with invasion by tamarisk.

Conversion to tamarisk typically

coincides with reduction or complete

loss of bird species strongly associated

with cottonwood-willow habitats. These

include the yellow-billed cuckoo

(Coccyzus americanus), summer tanager

(Piranga rubra), northern oriole (Icterus

galbula), and the southwestern willow

flycatcher (Hunter et al. 1987, Hunter et

al. 1988, Rosenberg et al. 1991). While

Brown and Trosset (1989) believed

tamarisk may serve as an ‘‘ecological

equivalent’’ to native vegetation, they

noted that their study occurred where a

tamarisk community became established

where no native equivalent existed

before.

Some authors believe tamarisk may

not provide the thermal protection that

native broadleaf species do (Hunter et

al. 1987, Hunter et al. 1988). This could

be important at lower elevations in the

Southwest, where extreme high

temperatures are common during the

bird’s midsummer breeding season. It is
Federal Register / Vol. 60, No. 38 / Monday, February 27, 1995 / Rules and Regulations 10709

also possible that tamarisk affects E. t.

extimus by altering the riparian insect

fauna (Carothers and Brown 1991).

Some sources also speculated that nests

in tamarisk stands may be more easily

located by brown-headed cowbirds (see

cowbird discussion below). Hunter et al.

(1987) reported the willow flycatcher as

one of seven midsummer-breeding

builders of open nests that were found

in tamarisk at higher elevations but not

lower elevations. Nesting E. t. extimus

have been found in tamarisk at middle

elevations (610–1200 m (2000–3500

feet)) (Hundertmark 1978, Hubbard

1987, Hunter et al. 1987, Brown 1988,

Sogge et al. 1993, Muiznieks et al.

1994). However, nest success in

tamarisk at these elevations appears to

be low (Sogge and Tibbitts 1992, Sogge

et al. 1993, Muiznieks et al. 1994). The

species is essentially absent from

tamarisk-dominated habitats below 610

m (2000 feet). On the lower Colorado

River (approximately 25 m (80 feet))

where tamarisk is widely dominant, the

only territories found in recent decades

were in relict stands dominated by

willow, cottonwood, and other native

vegetation (Muiznieks et al. 1994). Unitt

(1987) speculated that at higher

elevations and in the eastern portion of

its range, some E. t. extimus populations

may be adapting to tamarisk.

Water developments also likely

reduced and modified southwestern

willow flycatcher habitat. The series of

dams along most major southwestern

rivers (Colorado, Gila, Salt, Verde, Rio

Grande, Kern, San Diegito, and Mojave)

have altered riparian habitats

downstream of dams through

hydrological changes, vegetational

changes, and inundated habitats

upstream. New habitat is sometimes

created along the shoreline of reservoirs,

but this habitat (often tamarisk) is often

unstable because of fluctuating levels of

regulated reservoirs (Grinnell 1914,

Phillips et al. 1964, Rosenberg et al.

1991). Construction of Glen Canyon

Dam on the Colorado River allowed

establishment of a tamarisk riparian

community downstream in the Grand

Canyon, where a small population of E.

t. extimus exists, with poor

reproduction (Brown 1991, Sogge et al.

1993). However, Lake Powell, formed

upstream of the dam, inundated what

was apparently superior habitat, with E.

t. extimus considered common (Behle

and Higgins 1959).

Diversion and channelization of

natural watercourses are also likely to

have reduced E. t. extimus habitat.

Diversion results in diminished surface

flows and increased salinity of residual

flows. Consequent reductions and

composition changes in riparian

vegetation are likely. Channelization

often alters stream banks and fluvial

dynamics necessary to maintain native

riparian vegetation.

Suckling et al. (1992) suggested that

logging in the upper watersheds of

southwestern rivers may constitute

another potential threat to the

southwestern willow flycatcher. They

stated that logging increases the

likelihood of damaging floods in

southwestern willow flycatcher nesting

habitat.

Finally, the willow flycatcher (all

subspecies) is listed among neotropical

migratory birds that may be impacted by

alteration of wintering habitat, as

through tropical deforestation (Finch

1991, Sherry and Holmes 1993).

Population Trends for Each State Are

Discussed Briefly Below

California. All three resident

subspecies of the willow flycatcher (E.

t. extimus, E. t. brewsteri, and E. t.

adastus) were once considered widely

distributed and common in California,

wherever suitable habitat existed

(Wheelock 1912, Willett 1912, Grinnell

and Miller 1944). The historic range of

E. t. extimus in California apparently

included all lowland riparian areas of

the southern third of the State. Unitt

(1984, 1987) concluded that it was once

fairly common in the Los Angeles basin,

the San Bernardino/Riverside area, and

San Diego County. Willett (1912, 1933)

considered the bird to be a common

breeder in coastal southern California.

Nest and egg collections indicate the

bird was a common breeder along the

lower Colorado River near Yuma in

1902 (T. Huels, University of Arizona in

litt., transcripts of H. Brown’s field

notes).

All three willow flycatcher subspecies

breeding in California have declined,

with declines most critical in E. t.

extimus, which remains only in small,

disjunct nesting groups (Unitt 1984 and

1987, Gaines 1988, Schlorff 1990,

Service unpubl. data). Only two nesting

groups have been stable or increasing in

recent years. One is on private land

where habitat impacts from livestock

grazing have been virtually eliminated

(Harris et al. 1987, Whitfield 1990). This

group on the South Fork of the Kern

River experienced numerical declines in

1991 and 1992, but increases in nesting

success were realized in 1992 and 1993,

attributed to shaking (killing) or

removing cowbird eggs or nestlings

found in flycatcher nests, and trapping

cowbirds (Whitfield and Laymon, Kern

River Research Center, in litt. 1993). The

other apparently stable nesting group is

along the Santa Margarita River on

Marine Corps Base Camp Pendleton,

where cowbird numbers have also been

reduced by trapping (Griffith and

Griffith 1993). Approximately eight

other nesting groups are known in

southern California, all of which

consisted of six or fewer nesting pairs in

recent years (Unitt 1987, Schlorff 1990,

Service, unpubl. data). Using the most

recent information for all areas,

approximately 70 pairs and 8 single

southwestern willow flycatchers are

known to exist in California. Where

information on population trends since

the mid-1980’s is available, most areas

show declines. Three recent status

reviews considered extirpation from

California to be possible, even likely, in

the foreseeable future (Garrett and Dunn

1981, Harris et al. 1986, Schlorff 1990).

The State of California classifies the

willow flycatcher as endangered

[California Department of Fish and

Game (CDFG) 1992].

Arizona. Records indicate that the

former range of the southwestern willow

flycatcher in Arizona included portions

of all major watersheds (Colorado, Salt,

Verde, Gila, Santa Cruz, and San Pedro).

Historical records exist from the

Colorado River near Lee’s Ferry and

near the Little Colorado River

confluence (Phillips, pers. comm., cited

in Unitt 1987), and along the ArizonaCalifornia border (Phillips 1948, Unitt

1987), the Santa Cruz River near Tucson

(Swarth 1914, Phillips 1948), the Verde

River at Camp Verde (Phillips 1948), the

Gila River at Fort Thomas (W.C. Hunter,

pers. comm., cited in Unitt 1987), the

White River at Whiteriver, the upper

and lower San Pedro River (Willard

1912, Phillips 1948), and the Little

Colorado River headwaters area

(Phillips 1948).

The southwestern willow flycatcher

has declined throughout Arizona. The

subspecies was apparently abundant on

the lower Colorado River in 1902 (T.

Huels in litt., transcripts of H. Brown’s

field notes), but only four to five

territories were located in 1993

(Muiznieks et al. 1994). Elsewhere in

the State, E. t. extimus persists only in

several small, widely scattered

locations. In the Grand Canyon, several

groups of nesting birds have fluctuated

from a high of 11 singing males in 1986

(Brown 1988) to two pairs and three

single birds in 1992 (Sogge and Tibbitts

1992). Grand Canyon surveys in 1993

located 13 birds; six unpaired

individuals, two pairs, and what

appeared to be one male with two

females. No nesting attempts were

successful (Sogge et al. 1993). Although

Brown (et al. 1987) noted E. t. extimus

as nesting in Havasu Canyon, in 1993

none were located there and cowbirds

were abundant (Sogge et al. 1993). A
10710 Federal Register / Vol. 60, No. 38 / Monday, February 27, 1995 / Rules and Regulations

location on the lower San Pedro River

apparently supported relatively large

numbers of E. t. extimus in the 1940’s

(G. Monson, private individual, in litt.

1993 and pers. comm. 1993), but only a

single pair in 1978 and 1979, and none

in 1986 (Unitt 1987). Following habitat

improvements at this locale, six to seven

singing males were present in 1993, and

a total of 11 singing males were located

at two other locations on the lower San

Pedro in 1993 (Muiznieks et al. 1994).

Historically occupied habitat on the

upper San Pedro River is in the process

of rehabilitation, but remains

unoccupied by nesting E. t. extimus

(Krueper and Corman 1988, D. Krueper

unpubl. data). Two small groups at high

elevations in the White Mountains,

comprising approximately five singing

males each, have remained relatively

stable numerically from 1985 to 1993

(Muiznieks et al. 1994, Arizona Game

and Fish Department (AGFD), unpubl.

data). At a site on the Verde River in

central Arizona where R. Ohmart

(unpubl. data) observed four nesting

pairs in 1992, one pair and one single

male were present in 1993. The single

nest produced only a cowbird young. Of

13 river reaches in Arizona studied by

Hunter et al. (1987), nesting E. t.

extimus were extirpated from eight,

declining in two, and present in stable

numbers in three.

Statewide surveys in 1993 located

between 42 and 56 territorial males, and

all nest sites were considered vulnerable

to habitat loss and cowbird parasitism

(Muiznieks et al. 1994). Preliminary

data from 1994 surveys indicate that

approximately 70 to 80 breeding pairs

were found at a total of 12 locations in

the State. This included the discovery of

a group of flycatchers at one location

consisting of approximately 15 breeding

pairs. Brood parasitism by cowbirds was

documented at at least six (50%) of

those 12 sites. Brown-headed cowbirds

were documented at all 12 breeding

locations (Arizona Game and Fish

Department, in prep.).

Where information on population

trends since the mid-1980’s is available,

most areas show declines and/or high

rates of cowbird parasitism. In early

1993, catastrophic flooding on the

Verde, Gila, and San Pedro Rivers

temporarily damaged many sites

inhabited since the mid-1980’s, and

much potential habitat. Unitt (1987)

concluded that ‘‘Probably the steepest

decline in the population levels of E. t.

extimus has occurred in Arizona * * *

E. t. extimus has been extirpated from

much of the area from which it was

originally described, the riparian

woodlands of southern Arizona.’’ The

State of Arizona classifies the willow

flycatcher as endangered (AGFD 1988).

New Mexico. Bailey (1928) classified

breeding willow flycatchers in New

Mexico as E. t. brewsteri, according to

Oberholser’s (1918) taxonomy of that

time. Because of few records at that

time, she believed that either the bird

was rare or was overlooked by most

observers and collectors. More recently,

Hubbard (1987) reviewed and

summarized the flycatcher’s status in

New Mexico. He classified breeding

birds in the State as E. t. extimus and

reported breeding locations that were

generally confined to the regions west of

the Rio Grande, with records from the

Rio Grande, Chama, Zuni, San

Francisco, and Gila drainages (See also

Hubbard 1982). However, he

provisionally assigned all willow

flycatchers nesting in New Mexico to E.

t. extimus, noting records from the

Pecos River and Penasco Creek in the

southeast and from near Las Vegas in

the northeast.

Both Hubbard (1987) and Unitt (1987)

believed that the overall range of E. t.

extimus had not been reduced in New

Mexico, but that habitat and numbers

had declined. Unitt (1987) believed the

majority of all remaining nesting birds

may occur in New Mexico. Areas with

19 and 53 singing flycatchers, not

distinguished as nesting or migrants,

were found on the upper Gila River

(Montgomery et al. 1985, cited in

Suckling et al. 1992). Preliminary data

from 1994 surveys indicate that this

breeding group is still present. However,

the breeding status of flycatchers and

trend over time have not been

determined (S.O. Williams, New Mexico

Department of Game and Fish—pers.

comm.)

Hubbard (1987) noted that data were

lacking for trends of most nesting areas.

However, where data were available,

they indicated loss of a group of 15

breeding pairs by the rising waters of

Elephant Butte Reservoir. The willow

flycatcher was considered fairly

common in this area on the middle Rio

Grande in the late 1970’s (Hundertmark

1978). Hubbard hypothesized that some

of these birds could have moved

upstream, to new shoreline habitat

created by the impoundment. Between

1987 and 1990, bird surveys along the

Rio Grande Valley State Park in

Albuquerque found a single singing

willow flycatcher during the breeding

season (Hoffman 1990). Current trends

in New Mexico are not being

extensively monitored. However, in

1992, 71 transects along the Rio Grande

were surveyed for breeding birds, but

not specifically targeting willow

flycatcher habitat. A single willow

flycatcher was located near Espanola

(Leal, Meyer and Thompson, unpubl.

data). In 1993, surveys of 52 locations

found 31 pairs or singing males at 15 of

those locations (S.O. Williams III, New

Mexico Department of Game and Fish

(NMDGF), in litt. 1993). Hubbard (1987)

estimated that the State population may

total 100 pairs; that estimate has not

been revised. Hubbard (1987) found that

‘‘the conclusion is virtually inescapable

* * * a decrease has occurred in the

population of breeding willow

flycatchers in New Mexico over historic

time,’’ resulting from habitat loss. The

State of New Mexico classifies the

willow flycatcher as endangered

(NMDGF 1988).

Texas. The eastern limit of the

southwestern willow flycatcher’s

breeding range is in western Texas

(Unitt 1987). Collections have been

made at Fort Hancock on the Rio Grande

(Phillips 1948), in the Guadalupe

Mountains (Phillips, pers. comm., cited

in Unitt 1987), the Davis Mountains

(Oberholser 1974), and from unspecified

locales in Brewster County (Wolfe

1956). Wauer (1973 and 1985)

considered E. t. extimus a rare summer

resident in Big Bend National Park. Data

are lacking on current population levels

and trends in Texas. Loss and

modification of habitat may have

reduced populations on the Rio Grande

and Pecos Rivers.

Utah. The north-central limit of

breeding southwestern willow

flycatchers is in southern Utah. Behle

(1985) and Unitt (1987) believed a clinal

gradation between E. t. extimus and E.

t. adastus existed, but Browning (1993)

disagreed, identifying a range boundary

at approximately the 38th north parallel.

Southern Utah is characterized by

extreme topographic relief. In this

region, subspecific separation may be a

function of elevation, with E. t. extimus

at lower elevations (e.g., Virgin and

Colorado Rivers) and E. t. adastus

higher (e.g., Sevier River, wet meadows

of mountains and high plateaus).

Records that are likely to represent E. t.

extimus are from the Virgin River

(Phillips 1948, Wauer and Carter 1965,

Whitmore 1975), Kanab Creek, and

along the San Juan and Colorado Rivers

(Behle et al. 1958, cited in Unitt 1987;

Behle and Higgins 1959, Behle 1985; see

also Browning 1993). Other reports

document the subspecies being present

along the Virgin, Colorado, San Juan,

and perhaps Paria Rivers (BLM, unpubl.

data). Although Behle believed E. t.

extimus was always rare in southern

Utah overall (pers. comm. cited in Unitt

1987), he considered it a locally

common breeding resident where

habitat existed along the Colorado River
Federal Register / Vol. 60, No. 38 / Monday, February 27, 1995 / Rules and Regulations 10711

and its tributaries in southeastern Utah

(Behle and Higgins 1959).

Few data are available on population

trends in southern Utah. However, loss

and modification of habitat is likely to

have reduced populations on the Virgin,

Colorado, and San Juan Rivers. These

losses have been due to suburban

expansion and habitat changes along the

Virgin River, inundation by Lake Powell

on the Colorado and San Juan Rivers,

and encroachment of tamarisk

throughout the region (Unitt 1987, BLM

unpublished data).

Nevada. Unitt (1987) reported only

three records for Nevada, all made

before 1962. Unitt (1987), Hubbard

(1987), and Browning (1993) all

considered southern Nevada

(approximately south of 38° north

parallel) to be within the range of E. t.

extimus. However, no recent data are

available on population levels or trends.

Habitat may remain along the lower

Virgin River and at the inflow of the

Virgin River into Lake Mead. However,

loss and modification of habitat is likely

to have reduced populations on the

Virgin and Colorado Rivers.

Colorado. Whether or not the

southwestern willow flycatcher breeds

in Colorado is unclear. Hubbard (1987)

believed the subspecies ranged into

extreme southwestern Colorado,

Browning (1993) was noncommittal,

and Unitt (1987) tentatively used the

New Mexico-Colorado border as the

boundary between E. t. extimus and E.

t. adastus. Several specimens taken in

late summer have been identified as E.

t. extimus, but nesting was not

confirmed (Bailey and Niedrach 1965).

Phillips (1948) cautioned that willow

flycatchers in this region displayed

considerable individual variation and

may represent intergrades between E. t.

extimus and E. t. adastus. No recent

data are available on occurrence,

population levels, or trends in this area.

Mexico. Six specimens from Baja

California del Norte and two from

Sonora were discussed by Unitt (1987).

He and Phillips (pers. comm., cited in

Unitt 1987) believed E. t. extimus was

not common in northwestern Mexico.

Wilbur (1987) was skeptical of its

presence as a breeder in Baja California.

In the more general treatments of field

guides, the willow flycatcher is

described as breeding in extreme

northwestern Mexico, including

northern Baja California del Norte

(Blake 1953, Peterson 1973). No recent

data are available on current population

levels or trends.

Using the most recent censuses and

estimates for all areas, the estimated

total of all southwestern willow

flycatchers is approximately 300 to 500

nesting pairs. Unitt (1987) believed the

total was ‘‘well under’’ 1000 pairs, more

likely 500. The regional estimates and

information on which these total

estimates are based generally date from

the late 1980’s to 1993 (e.g., Hubbard

1987, T. Johnson 1989). Virtually all

nesting groups monitored since that

time have continued to decline

(Whitfield 1990, Brown 1991, Sogge et

al. 1993, Whitfield and Laymon,

unpubl. data).

B. Overutilization for Commercial,

Recreational, Scientific, or Educational

Purposes

The Service is unaware of threats

resulting from overutilization.

C. Disease or Predation

The Service is unaware of any disease

that constitutes a significant threat to E.

t. extimus. Boland et al. (1989) found

only one case of larval parasites in

willow flycatcher nestlings in

California.

Predation of southwestern willow

flycatchers may constitute a significant

threat and may be increasing with

habitat fragmentation. Where E. t.

extimus has been extirpated in the lower

Colorado River valley, Rosenberg et al.

(1991) found increases in the greattailed grackle (Quiscalus mexicanus),

which preys on the eggs and young of

other birds (Bent 1965). Whitfield (1990)

found predation on E. t. extimus nests

to be significant. Predation increased

with decreasing distance from nests to

thicket edges, suggesting that habitat

fragmentation may increase the threat of

predation.

D. The Inadequacy of Existing

Regulatory Mechanisms

The Migratory Bird Treaty Act

(MBTA)(16 U.S.C. § 703–712) is the only

current Federal protection provided for

the southwestern willow flycatcher. The

MBTA prohibits ‘‘take’’ of any migratory

bird, which is defined as: ‘‘* * * to

pursue, hunt, shoot, wound, kill, trap,

capture, or collect, or attempt to pursue,

hunt, shoot, wound, kill, trap, capture,

or collect * * *’’ However, unlike the

Act, there are no provisions in the

MBTA preventing habitat destruction

unless direct mortality or destruction of

active nests occurs.

The majority of the southwestern

willow flycatcher’s range lies within

California, Arizona, and New Mexico

(Phillips 1948, Hubbard 1987, Unitt

1987). All of those States classify the

willow flycatcher as endangered (AGFD

1988, NMDGF 1988, CDFG 1992). The

State listings in New Mexico and

Arizona do not convey habitat

protection or protection of individuals

beyond existing regulations on capture,

handling, transportation, and take of

native wildlife. The California

Endangered Species Act (CESA)

prohibits unpermitted possession,

purchase, sale, or take of listed species.

However, the CESA definition of take

does not include harm, which under the

Act can include destruction of habitat

that actually kills or injures wildlife by

significantly impairing essential

behavioral patterns (50 CFR 17.3).

However, CESA requires consultation

between the CDFG and other State

agencies to ensure that activities of State

agencies will not jeopardize the

continued existence of State-listed

species (E. Toffoli, State of California, in

litt. 1992). The Service believes that this

and other regulatory mechanisms are

inadequate to ensure the continued

existence of the southwestern willow

flycatcher.

E. Other Natural or Manmade Factors

Affecting Its Continued Existence

The riparian habitat of the

southwestern willow flycatcher has

always been rare and has become more

so. Its habitat rarity and small, isolated

populations make the remaining E. t.

extimus increasingly susceptible to local

extirpation through stochastic events

such as floods, fire, brood parasitism,

predation, depredation, and land

development. In early 1993,

catastrophic floods in southern

California and Arizona impacted much

of the remaining occupied or potential

breeding habitat. Historically, these

floods have always destroyed habitat

but were also important events in

regenerating cottonwood-willow

communities. However, with little

southwestern willow flycatcher habitat

remaining, widespread events like those

of 1993 could destroy virtually all

remaining habitat throughout all or a

significant portion of the subspecies’

range. Further, regeneration with

natural vegetation after floods may be

inhibited if the area is subjected to

overgrazing by domestic livestock.

The disjunct nature of habitats and

small breeding populations impede the

flow of genetic material and reduce the

chance of demographic rescue from

migration from adjacent populations.

The resulting constraints on the gene

pool intensify the external threats to the

species.

Brood parasitism by the brownheaded cowbird also threatens the

southwestern willow flycatcher.

Cowbirds lay their eggs in the nests of

other, usually smaller, songbirds. The

cowbird often removes a number of the

host’s eggs and replaces them with an

equal number of cowbird eggs. The host
10712 Federal Register / Vol. 60, No. 38 / Monday, February 27, 1995 / Rules and Regulations

species then incubates the cowbird eggs,

which typically hatch prior to the host’s

own eggs. Cowbird eggs require a

relatively short incubation period of 10

to 12 days. Thus, the young cowbirds

have several advantages over the host’s

young; they hatch earlier, they are

larger, and they are also more aggressive

than the host’s young. Cowbird

nestlings typically outcompete those of

the host species for parental care, and,

as a result, the host species’ own

reproduction is reduced or eliminated

(Bent 1965, McGeen 1972, Mayfield

1977a, Harrison 1979, Brittingham and

Temple 1983).

The brown-headed cowbird

commonly preys on insects stirred up

by grazing ungulates, and was originally

restricted to the Great Plains, where it

was strongly associated with American

bison (Bison bison). As North America

was settled, cowbirds became associated

with livestock and human agriculture

because of the food sources they

provided (Bent 1965, Flett and Sanders

1987, Valentine et al. 1988). The

expansion of agriculture, livestock

grazing, and wide scale human activities

in general caused opening and

fragmenting of forest and woodland

habitats. Habitat fragmentation and

agriculture are strongly correlated with

increased rates of brood parasitism by

brown-headed cowbirds (Rothstein et al.

1980, Brittingham and Temple 1983,

Airola 1986, Robinson et al. 1993).

Some species are likely to have adapted

to parasitism over time, particularly

prairie nesters in the original range of

the cowbird. However, the cowbird’s

rapid expansion now brings it into

contact with forest and woodland

species not adapted to deal with brood

parasitism, significantly impacting those

species (Hill 1976, Mayfield 1977a,

Robinson et al. 1993).

The brown-headed cowbird was

apparently an uncommon bird within

the range of E. t. extimus, until the late

1800’s. Since then, the species has

greatly expanded in numbers and

distribution throughout the region

(Laymon 1987, Rothstein in prep.).

Increases in cowbirds in the San

Bernardino Valley between 1918 and

1928 caused Hanna (1928)

‘‘considerable alarm.’’ Although

Friedmann et al. (1977) reported

relatively low rates of parasitism of

willow flycatchers in the western

United States, this was apparently

owing to their data (egg sets) being

collected prior to the major incursions

of cowbirds into Pacific coast riparian

habitats (L. Kiff, Western Foundation for

Vertebrate Zoology, in litt. 1993). Brood

parasitism of several subspecies of the

willow flycatcher, including E. t.

extimus, by brown-headed cowbirds is

well documented (Hanna 1928, Rowley

1930, Willett 1933, Hicks 1934, King

1954, Holcomb 1972, Friedmann et al.

1977, Garret and Dunn 1981, Harris et

al. 1987, Brown 1988, 1991, Sedgewick

and Knopf 1988, Whitfield 1990, Harris

1991, Sogge et al. 1993, Muiznieks et al.

1994).

The increases in cowbirds in the

Southwest and parasitism of E. t.

extimus and other birds are generally

attributed to the following scenario: The

introduction of modern human

settlements, livestock grazing, and other

agricultural developments resulted in

habitat fragmentation. Simultaneously,

livestock grazing and other agricultural

developments served as vectors for

cowbirds by providing feeding areas

near host species’ nesting habitats

(Hanna 1928, Gaines 1974, Mayfield

1977a). Cowbirds may travel almost 7

kilometers (4.2 miles) from feeding sites

where livestock congregate to areas

where host species are parasitized

(Rothstein et al. 1984). These factors

increased both the vulnerability of E. t.

extimus and the likelihood of

encounters with cowbirds. Finally, the

high edge-to-interior ratio of linear

riparian habitats like those used by E. t.

extimus renders birds nesting there

particularly vulnerable to parasitism

(Airola 1986, Laymon 1987, Harris

1991). Linear riparian habitats are also

especially vulnerable to fragmentation

by grazing, which further increases both

the edge-to-interior ratio and the threat

of parasitism.

The effects of parasitism by brownheaded cowbirds on willow flycatchers

include reducing nest success rate and

egg-to-fledging rate, and delaying

successful fledging (because of renesting

attempts) (Harris 1991). A common

response to parasitism is abandonment

of the nest (Holcomb 1972). Willow

flycatchers may also respond to

parasitism by ejecting cowbird eggs, by

burying them with nesting material and

renesting on top of them, or by renesting

in another nest (Harris et al. 1991).

However, the success rate of renesting is

often reduced, because these attempts

produce fledglings several weeks later

than normal, which may not allow them

adequate time to prepare for migration

(Harris 1991). Renesting also usually

consists of smaller clutches, further

reducing overall reproductive potential

(Holcomb 1974).

McCabe (1991) downplayed the

significance of cowbird parasitism as a

threat to any species except Kirtland’s

warbler (Dendroica kirtlandii).

McCabe’s monograph focussed on the

combined ‘‘Traill’s flycatcher’’

superspecies, comprised of E. t. traillii

and E. alnorum in marshy habitats in

the upper Midwest, where parasitism

rates ranged from 3 percent to 19

percent. However, perhaps reflecting his

regional perspective, he characterized

the high parasitism rates on willow

flycatchers reported by Trautman (1940,

cited in McCabe 1991) and Sedgwick

and Knopf (1988) as aberrant (56

percent and 41 percent, respectively).

McCabe considered the high rates the

result of the ‘‘* * * linear configuration

of the habitat * * * [c]owbirds lay eggs

in songbird nests closest to cover edge.’’

The vast majority of southwestern

willow flycatcher habitat is very linear

and may experience higher rates of

parasitism than other willow flycatcher

subspecies.

Brittingham and Temple (1983)

considered ‘‘high’’ parasitism rates

(percent of nests parasitized) to be 24

percent, with some as high as 72

percent. Mayfield (1977a) thought a

species (or population) might be able to

survive a 24 percent parasitism rate, but

that losses much higher than that

‘‘would be alarming.’’ Parasitism rates of

72 percent to 83 percent on Kirtland’s

warbler (Mayfield 1977b) resulted in a

precipitous population decline. Where

parasitism rates are known for E. t.

extimus, they are comparable to rates for

Kirtland’s warbler and are capable of

causing similar declines. In California,

parasitism rates ranged from 50 percent

to 80 percent between 1987 and 1992,

when an estimated population size

decreased from 44 to 28 nesting pairs

(Whitfield 1990, Harris et al. 1991,

Whitfield and Laymon, unpubl. data).

These parasitism rates were considered

minimum measures, because several

nests were abandoned each year due to

unknown causes, which could have

been parasitism. Brown (1988) reported

an average 50 percent parasitism rate in

the Grand Canyon between 1982 and

1987. Although his estimated

population increased from two pairs to

11 during that period, it has since

decreased back as low as two nesting

pairs (Brown 1991, Sogge and Tibbitts

1992). In 1993, parasitism reached 100

percent in the Grand Canyon, and no E.

t. extimus were fledged (Sogge et al.

1993). Harris et al. (1991) believed that

the parasitism rates observed on the

Kern River in 1987 (68 percent of all

nests, 88 percent of all nest territories)

were high enough to prevent E. t.

extimus from recolonizing lowland

riparian habitat, even if it were restored.

Rothstein et al. (1980), Stafford and

Valentine (1985), and Harris (1991)

believed parasitism may be correlated

with elevation, being more severe at

lower elevations. Coupled with greater

loss of lowland (desert) riparian habitat,
Federal Register / Vol. 60, No. 38 / Monday, February 27, 1995 / Rules and Regulations 10713

the effects of habitat loss and parasitism

are compounded. However, cowbirds

now appear to be increasing at higher

elevations (Hanka 1985).

In addition to causing habitat

degradation and facilitating brood

parasitism, livestock grazing in and near

riparian areas may also threaten E. t.

extimus through direct mortality.

Livestock in riparian habitats sometimes

make physical contact with nests or

supporting branches, resulting in

destruction of nests and spillage of eggs

or nestlings. All known documentation

of this threat involves E. t. brewsteri,

perhaps because virtually all known

remaining populations of E. t. extimus

are in ungrazed habitats (Serena 1982,

Harris et al. 1987, Whitfield and

Laymon, unpubl. data). Valentine et al.

(1988) studied willow flycatchers in

California from 1983 through 1987,

when 11 of their 20 recorded nesting

attempts failed. They found that ‘‘Prior

to reduction of grazing intensity in

1987, livestock accounted for 36 percent

of the failed nests or 20 percent of all

nesting attempts. In addition, livestock

destroyed four successful nests shortly

after the young had fledged.’’ Stafford

and Valentine (1985) reported that three

of eight (37.5 percent) willow flycatcher

nests in their study site were probably

destroyed by cattle. Flett and Sanders

(1987) documented no nest upsets due

to livestock but noted the vulnerability

of nests to upset, due to their placement

low in willow clumps (see also Serena

1982). Livestock grazing may affect E. t.

extimus similarly.

The southwestern willow flycatcher’s

preference for, and former abundance

in, floodplain areas that are now largely

agricultural may indicate a potential

threat from pesticides. Where flycatcher

populations remain, they are sometimes

in proximity to agricultural areas, with

the associated pesticides and herbicides.

Without appropriate precautions, these

agents may potentially affect the

southwestern willow flycatcher through

direct toxicity or effects on their insect

food base. No quantitative data on this

potential threat are known at this time.

Recreation that is focused on riparian

areas, particularly during warm summer

breeding months, may also constitute a

threat to E. t. extimus. Taylor (1986)

found a possible correlation between

recreational activities and decreased

riparian bird abundance. Blakesley and

Reese (1988) reported the willow

flycatcher (probably E. t. adastus) as one

of seven species negatively associated

with campgrounds in riparian areas in

northern Utah. It is unknown whether

these possible effects involve impacts to

habitat or disturbance of nesting birds.

The Service has carefully assessed the

best scientific and commercial

information available regarding the past,

present, and future threats faced by this

species in determining to make this rule

final. Based on this evaluation, the

preferred action is to list the

southwestern willow flycatcher as

endangered. A decision regarding

designation of critical habitat for this

species is being deferred, and a final

decision regarding the designation will

be made by July 23, 1995. Critical

habitat for this species is not now

determinable.

Critical Habitat

Critical Habitat is defined in section

3 of the Act as (i) the specific areas

within the area occupied by a species,

at the time it is listed in accordance

with the Act, on which are found those

physical or biological features (I)

essential to the conservation of the

species and (II) that may require special

management considerations or

protection and; (ii) specific areas

outside the geographical area occupied

by a species at the time it is listed, upon

a determination that such areas are

essential for the conservation of the

species. ‘‘Conservation’’ means the use

of all methods and procedures needed

to bring the species to a point at which

listing under the Act is no longer

necessary.

Section 4(a)(3) of the Act and

implementing regulations (50 CFR

424.12) require that, to the maximum

extent prudent and determinable, the

Secretary designate critical habitat at the

time a species is determined to be

endangered or threatened. Critical

habitat was proposed to be designated

for the flycatcher at the time it was

proposed for listing as endangered to

encompass approximately 640 miles

(1000 km) of riparian zones in the States

of California, Arizona, and New Mexico.

After reviewing comments submitted

during the public comment period the

Service is deferring the designation of

critical habitat for this endangered

species. The Service received numerous

comments on the proposed rule,

including many recommendations for

additions and deletions to proposed

critical habitat. The Service is reviewing

these comments as well as survey data

collected in 1994. These sources

included more complete information on

the primary constituent elements of

flycatcher habitat and on the

distribution of that habitat across the

bird’s range. Substantial disagreement

has also been found among scientists

knowledgeable about the species

regarding the proposed designations.

Further, written comments submitted by

State agencies recommended substantial

changes in proposed critical habitat

areas.

The Service is presently reconsidering

the prudence of critical habitat

designation for this species, the need for

special management considerations or

protection of habitat within the species’

range, and the proper boundaries of any

areas that might be designated as critical

habitat. Issues raised in public

comments, new information, and the

lack of the economic information

necessary to perform the required

economic analysis cause the Service to

conclude that critical habitat is not now

determinable and to invoke an

extension until July 23, 1995, pursuant

to 16 U.S.C. § 1533(b)(6)(C) for reaching

a final decision on the proposal of

critical habitat for the flycatcher. The

Service has determined that this is in

compliance with provisions of 50 CFR

424.12(a) and § 424.17, regarding

delaying final rules on proposed critical

habitat designations, and with

provisions for addressing State agencies

that disagree in whole or part with a

proposed rule (50 CFR 424.18(c)). In

order to assist in its deliberation, the

Service is reopening comment on the

proposal to designate critical habitat for

a period of 60 days. Comments are

particularly sought on the following

topics:

1. The need for special management

of areas within the range of the

flycatcher, including those proposed as

critical habitat as well as other areas,

2. The net benefit to the flycatcher in

addition to the protection provided by

its listing as endangered likely to accrue

from a designation of critical habitat,

and

3. Any indication that areas should be

added to or excluded from those

proposed for designation.

Comments already received that

address the above topics will be

considered in reaching a final decision

regarding critical habitat designation,

and need not be resubmitted.

Available Conservation Measures

Conservation measures provided to

species listed as endangered or

threatened under the Act include

recognition, recovery actions,

requirements for Federal protection, and

prohibitions against certain practices.

Recognition through listing encourages

and results in conservation actions by

Federal, State, and local agencies,

private organizations, and individuals.

The Act provides for possible land

acquisition and cooperation with the

States and requires that recovery actions

be carried out for all listed species. The

protection required of Federal agencies
10714 Federal Register / Vol. 60, No. 38 / Monday, February 27, 1995 / Rules and Regulations

and the prohibitions against taking and

harm are discussed, in part, below.

Section 7(a) of the Act, as amended,

requires Federal agencies to evaluate

their actions with respect to any species

that is proposed or listed as endangered

or threatened and with respect to its

critical habitat, if any is being

designated. Regulations implementing

this interagency cooperation provision

of the Act are codified at 50 CFR Part

402. Section 7(a)(4) requires Federal

agencies to confer informally with the

Service on any action that is likely to

jeopardize the continued existence of a

proposed species or result in

destruction or adverse modification of

proposed critical habitat. If a species is

listed subsequently, Section 7(a)(2)

requires Federal agencies to ensure that

activities they authorize, fund, or carry

out are not likely to jeopardize the

continued existence of such a species or

destroy or adversely modify its critical

habitat. If a Federal action may affect a

listed species or its critical habitat, the

responsible Federal agency must enter

into consultation with the Service.

No conservation plans or habitat

restoration projects specific to the

southwestern willow flycatcher exist on

lands managed by the U.S. Forest

Service (USFS), BLM, U.S. Bureau of

Reclamation (Reclamation), Indian

Nations, State agencies, or the Service.

The USFS and BLM have focussed some

attention on modifying livestock grazing

practices in recent years, particularly as

they affect riparian ecosystems. As

mitigation for other projects impacting

riparian habitats, Reclamation is

engaged in riparian habitat restoration

projects in several areas in the range of

E. t. extimus, including some historical

nesting locations. The BLM currently

manages approximately 40 miles of the

upper San Pedro River in Arizona

(including historic nest sites), as a

Riparian National Conservation Area.

Riparian habitat rehabilitation is also

underway at several National Wildlife

Refuges in the breeding range of E. t.

extimus, which are managed by the

Service. The Nature Conservancy

manages one of the largest remaining

flycatcher populations, as well as

several other areas with high recovery

potential. The U.S. Marines have

maintained a cowbird control program

near the Santa Margarita River to benefit

the least Bell’s vireo. This program has

benefitted nesting southwestern willow

flycatchers there. Grand Canyon

National Park has instituted a seasonal

recreation closure at the remaining site

with nesting willow flycatchers in the

Grand Canyon, and has begun a cowbird

monitoring program.

The Act and implementing

regulations found at 50 CFR 17.21 set

forth a series of general prohibitions and

exceptions that apply to all endangered

wildlife. These prohibitions, in part,

make it illegal for any person subject to

the jurisdiction of the United States to

take (includes harass, harm, pursue,

hunt, shoot, wound, kill, trap, or collect;

or to attempt any of these), import or

export, ship in interstate commerce in

the course of commercial activity, or sell

or offer for sale in interstate or foreign

commerce any listed species. It also is

illegal to possess, sell, deliver, carry,

transport, or ship any such wildlife that

has been taken illegally. Certain

exceptions apply to agents of the

Service and State conservation agencies.

Permits may be issued to carry out

otherwise prohibited activities

involving endangered wildlife species

under certain circumstances.

Regulations governing permits are at 50

CFR 17.22 and 17.23. Such permits are

available for scientific purposes, to

enhance the propagation or survival of

the species, and/or for incidental take in

connection with otherwise lawful

activities.

It is the policy of the Service (59 FR

34272) to identify to the maximum

extent practicable at the time a species

is listed those activities that would or

would not constitute a violation of

section 9 of the Act. The intent of this

policy is to increase public awareness of

the effect of a listing on proposed and

ongoing activities within a species’

range. The Service believes that, based

on the best available information, the

following are examples of actions that

will not result in a violation of section

9:

(1) Dispersed recreational activities

near willow flycatcher breeding areas

that do not disrupt normal flycatcher

breeding activities and behavior, attract

avian and mammalian predators, nor

result in the trampling or destruction of

riparian breeding habitat;

(2) Federally-approved projects that

involve activities such as discharge of

fill material, draining, ditching, tiling,

pond construction, stream

channelization or diversion, or

diversion or alteration of surface or

ground water flow into or out of the

wetland (i.e., due to roads,

impoundments, discharge pipes,

stormwater detention basins, etc.)—

when such activity is conducted in

accordance with any reasonable and

prudent measures given by the Service

in accordance with section 7 of the Act;

and

(3) Livestock grazing that does not

attract the brood parasitic brown-headed

cowbird or result in the destruction of

riparian habitat or the disturbance of

breeding flycatchers.

Activities that the Service believes

could potentially harm the

southwestern willow flycatcher and

result in ‘‘take,’’ include, but are not

limited to:

(1) Unauthorized handling or

collecting of the species;

(2) Destruction/alteration of the

species’ habitat by discharge of fill

material, draining, ditching, tiling, pond

construction, stream channelization or

diversion, or diversion or alteration of

surface or ground water flow into or out

of the wetland (i.e., due to roads,

impoundments, discharge pipes,

stormwater detention basins, etc.);

(3) Livestock grazing that results in

direct or indirect destruction of riparian

habitat;

(4) Activities such as continued

presence of cattle and fragmentation of

flycatcher habitat that facilitate brood

parasitism by the brown-headed

cowbird; and

(5) Pesticide applications in violation

of label restrictions.

Questions as to whether specific

activities will constitute a violation of

section 9 should be directed to Sam F.

Spiller or Robert M. Marshall at the

Service’s Ecological Services State

Office, 2321 West Royal Palm Road,

Suite 103, Phoenix, Arizona 85021

(Telephone 602/640–2720)

National Environmental Policy Act

The Fish and Wildlife Service has

determined that an Environmental

Assessment and Environmental Impact

Statements, as defined under the

authority of the National Environmental

Policy Act of 1969, need not be

prepared in connection with regulations

adopted pursuant to Section 4(a) of the

Act. A notice outlining the Service’s

reasons for this determination was

published in the Federal Register on

October 25, 1983 (48 FR 49244).

References Cited

A complete list of all references cited

herein, as well as others, is available

upon request from the Supervisor,

Ecological Services State Office in

Arizona (see ADDRESSES above).

Author

The primary author of this rule is

Robert M. Marshall, Ecological Services

State Office in Arizona (see ADDRESSES

above).

List of Subjects in 50 CFR Part 17

Endangered and threatened species,

Exports, Imports, Reporting and record

keeping requirements, and

Transportation.
Federal Register / Vol. 60, No. 38 / Monday, February 27, 1995 / Rules and Regulations 10715

Regulation Promulgation

Accordingly, part 17, subchapter B of

chapter I, title 50 of the Code of Federal

Regulations, is amended as set forth

below:

PART 17—[AMENDED]

1. The authority citation for Part 17

continues to read as follows:

Authority: 16 U.S.C. 1361–1407; 16 U.S.C.

1531–1544; 16 U.S.C. 4201–4245; Pub. L. 99–

625, 100 Stat. 3500; unless otherwise noted.

2. Section 17.11(h) is amended by

adding the following, in alphabetical

order under Birds, to the List of

Endangered and Threatened Wildlife to

read as follows:

§ 17.11 Endangered and threatened

wildlife.

* * * * *

(h) * * *

Species

Historic range

Vertebrate population where endangered or threatened

Status When listed Critical

habitat

Special

rules Common name Scientific name

* * * * * * *

BIRDS

* * * * * * *

Flycatcher, southwestern willow.Empidonax traillii,

extimus.

U.S.A. (AZ, CA, CO,

NM, NV, TX, UT).

Entire ..................... E 577 NA NA

* * * * * * *

Dated: February 16, 1995.

Mollie H. Beattie,

Director, Fish and Wildlife Service.

[FR Doc. 95–4531 Filed 2–24–95; 8:45 am]

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