[Federal Register: February 17, 2000 (Volume 65, Number 33)]
[Proposed Rules]               
[Page 8104-8107]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]



Fish and Wildlife Service

50 CFR Part 17

Endangered and Threatened Wildlife and Plants; Notice of 90-Day 
Finding for a Petition To List the Yellow-billed Cuckoo as Endangered 
and Commencement of a Status Review

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 90-day petition finding.


SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 
90-day finding on a petition to list the yellow-billed cuckoo (Coccyzus 
americanus) as endangered, with critical habitat, pursuant to the 
Endangered Species Act (Act) of 1973, as amended. We find that the 
petition presents substantial scientific or commercial information to 
indicate that the listing of the yellow-billed cuckoo may be warranted. 
Therefore, we are initiating a status review to determine if the 
petitioned action is warranted. To ensure that the review is 
comprehensive, we are soliciting information and data regarding this 

DATES: The finding in this document was made on February 7, 2000. To be 
considered in the status review and subsequent 12-month finding for the 
petition, your information and comments must be received by April 17, 

ADDRESSES: You may submit data, information, comments, or questions 
concerning this finding to the Field Supervisor, U.S. Fish and Wildlife 
Service, Sacramento Fish and Wildlife Office, 2800 Cottage Way, Room W-
2605, Sacramento, California 95825. The petition finding, supporting 
data, and comments are available for public inspection, by appointment, 
during normal business hours at the above address.

FOR FURTHER INFORMATION CONTACT: Karen Miller at the Sacramento Fish 
and Wildlife Office (see ADDRESSES section above), or at 916/414-6600.



    Section 4(b)(3)(A) of the Endangered Species Act (Act) of 1973, as 
amended (16 U.S.C. 1531 et seq.), requires that we make a finding on 
whether a petition to list, delist, or reclassify a species presents 
substantial information indicating that the petitioned action may be 
warranted. To the maximum extent practicable, we must make this finding 
within 90 days of the receipt of the petition and publish it promptly 
in the Federal Register. If the finding is that substantial information 
was presented, we are also required to promptly commence a review of 
the status of the involved species. This finding is based on 
information contained in the petition, supporting information submitted 
with the petition, and information otherwise available to us at the 
time the finding was made. While the Act does not provide for petitions 
to designate critical habitat, the specific critical habitat 
designation is petitionable under the Administrative Procedures Act. As 
required by section 4(a)(3) of the Act, we will consider critical 
habitat designation if we determine that listing is warranted.
    The processing of this petition conforms with our Listing Priority 
Guidance published in the Federal Register on October 22, 1999 (64 
FR57114). The guidance clarifies the order in which we will process 
rulemakings. Highest priority is processing emergency listing rules for 
any species determined to face a significant and imminent risk to its 
well-being (Priority 1). Second priority (Priority 2) is processing 
final determinations on proposed additions to the lists of endangered 
and threatened wildlife and plants. Third priority is processing new 
proposals to add species to the lists. The processing of administrative 
petition findings (petitions filed under section 4 of the Act) is the 
fourth priority. The processing of this 90-day petition finding is a 
Priority 4 action and is being completed in accordance with the current 
Listing Priority Guidance.
    We were previously petitioned to list the western yellow-billed 
cuckoo (Coccyzus americanus occidentalis) in 1986 as endangered in the 
States of California, Washington, Oregon, Idaho, and Nevada (Manolis et 
al. 1986). We received this petition from Dr. Tim Manolis, Western 
Field Ornithologists, and it was cosigned by the Animal Protection 
Institute, Defenders of Wildlife, Sacramento River Preservation Trust, 
Friends of the River, Planning and Conservation League, Davis

[[Page 8105]]

Audubon Society, Sacramento Audubon Society, and the Sierra Club. We 
published a 90-day finding on January 21, 1987, in the Federal Register 
(52 FR 2239) that the petition presented substantial information 
indicating that the requested action may be warranted. We acknowledged, 
in that finding, the difficulties in defining distinct, biologically 
defensible populations of western yellow-billed cuckoos for possible 
listing, and the existence of gaps in available information as to its 
status in certain parts of its range. We published a 12-month finding 
on December 29, 1988, in the Federal Register (53 FR 52746) that the 
petitioned action was not warranted, finding that the petitioned area 
did not encompass either a distinct subspecies or a distinct population 
segment. The finding cited--(1) a study of geographic variation in the 
species that concluded the morphological differences between eastern 
and western birds were too small to merit separate subspecies (Banks 
1988), and (2) that the petitioned area did not encompass a distinct 
population segment. It noted that yellow-billed cuckoos near a State 
line within the petitioned area, such as on the California side of the 
lower Colorado River, are part of the same population and interbreed 
with birds immediately across the same State border and outside the 
petitioned area.
    We received another petition on February 9, 1998, and dated 
February 2, 1998, to list the yellow-billed cuckoo (Coccyzus 
americanus) as an endangered species. The petition was submitted by 
Robin Silver, Kieran Suckling, and David Noah Greenwald of Southwest 
Center for Biological Diversity on behalf of 22 groups. The 22 groups 
are the Maricopa Audubon Society, Tucson Audubon Society, Huachuca 
Audubon Society, White Mountain Audubon Society, White Mountain 
Conservation League, Wildlife Damage Review, Sky Island Alliance, San 
Pedro 100, Zane Grey Chapter of Trout Unlimited, T and E Inc., 
Biodiversity Legal Foundation, Environmental Protection Information 
Center, Sierra Nevada Alliance, Wetlands Action Network, Rangewatch, 
Oregon Natural Desert Association, Oregon Natural Resources Center, 
Klamath-Siskiyou Wildlands Center, Southern Utah Wilderness Alliance, 
Wild Utah Forest Campaign, Friends of Nevada Wilderness, and Toiyabe 
Chapter of the Sierra Club. The petitioners requested that we list the 
yellow-billed cuckoo as endangered, stating that they believe the 
yellow-billed cuckoo ``is endangered in a significant portion of its 
range (i.e., the western United States).'' The petitioners also stated 
they ``believe this range of endangerment is coterminous with a valid 
subspecies, the western yellow-billed cuckoo (Coccyzus americanus 
occidentalis)'' and that they would concur with a decision to list only 
this subspecies. The petitioners also requested that critical habitat 
be designated. Included in the petition was supporting information 
relating to the species' taxonomy and ecology, adequacy of existing 
regulatory mechanisms for the species, the historic and present 
distribution, current status, and causes of decline in the western 
United States. This notice announces our 90-day finding for the 1998 
    The yellow-billed cuckoo is a medium-sized bird of about 30 
centimeters (12 inches) in length, and weighing about 60 grams (2 
ounces). The species has a slender, long-tailed profile, with a fairly 
stout and slightly down-curved bill, which is blue-black with yellow on 
the basal half of the lower mandible (bill). Plumage is grayish-brown 
above and white below, with rufous primary flight feathers. The tail 
feathers are boldly patterned with black and white below. The legs are 
short and bluish-gray, and adults have a narrow, yellow eye ring. 
Juveniles resemble adults, except the tail patterning is less distinct, 
and the lower bill may have little or no yellow. Males and females 
differ slightly. Males tend to have a slightly larger bill, and the 
white in the tail tends to form oval spots, whereas in females the 
white spots tend to be connected and less distinct (Hughes 1999).
    In the west, based on historic accounts, the species was widespread 
and locally common in California and Arizona; locally common in a few 
river reaches in New Mexico; common very locally in Oregon and 
Washington; generally local and uncommon in scattered drainages of the 
arid and semiarid portions of western Colorado, western Wyoming, Idaho, 
Nevada, and Utah; and, probably uncommon and very local in British 
Columbia. Hughes (1999) summarizes the species' historic range and 
status in these areas. The species was listed by the State of 
California as threatened in 1971 and was reclassified as endangered in 
1987. Based on a 1986-87 statewide survey, only three areas in the 
State support more than about five breeding pairs on a regular basis. 
In the Pacific Northwest, the last confirmed breeding records were in 
the 1930s in Washington and in the 1940s in Oregon. The species may now 
be extirpated from Washington. Arizona probably contains the largest 
remaining cuckoo population among States west of the Rocky Mountains, 
but cuckoo numbers in 1999 are substantially less than some previous 
estimates for Arizona as habitat has declined. In Colorado and Idaho, 
the species is rare, and in Nevada, the remaining breeding populations 
are threatened with extinction, if not already extirpated (Hughes 
1999). The portion of Texas west of the Pecos River has been identified 
as within the range of the historic western subspecies (Oberholser and 
Kincaid 1974), but other authors consider birds from this area most 
similar to eastern cuckoos (Hughes 1999). The species still occurs in 
this area, but its conservation status is unknown (Groschupf 1987). The 
species is widespread and uncommon to common in central and eastern 
Texas (Oberholser and Kincaid 1974; Rappole and Blacklock 1994).
    The species breeds from extreme southern Canada (Quebec and 
Ontario) south to the Greater Antilles and Mexico (American 
Ornithologist Union (AOU) 1998). The cuckoo occurs widely and is an 
uncommon to common breeding bird in the United States east of the 
Continental Divide. Habitat for the species in the eastern United 
States, mainly riparian and other broad-leaved woodlands, is 
widespread. This habitat is in contrast to habitat west of the 
Continental Divide, where suitable habitat is limited to narrow, and 
often widely separated, riparian patches. Distribution, population, and 
trend data we obtained from the Breeding Bird Survey (BBS) program and 
other available sources indicate that, although regional declines have 
occurred, the yellow-billed cuckoo is relatively common as a breeding 
bird in much of the eastern United States (Oberholser and Kincaid 1974; 
Rappole and Blacklock 1994; BBS 1999; Hughes 1999).
    The petitioners included information on factors affecting the 
species in the western United States, which they define as the historic 
range of the western subspecies. The petition identifies habitat loss, 
overgrazing, tamarisk invasion of riparian areas, river management, 
logging, and pesticides as causes of decline. These factors are 
consistent with loss, degradation, and fragmentation of riparian 
habitat as the primary factor causing yellow-billed cuckoo declines in 
the western United States. Estimates of riparian habitat losses include 
90-95 percent for Arizona, 90 percent for New Mexico, 90-99 percent for 
California, and more than 70 percent nationwide (Noss et al. 1995; 
Ohmart 1994). Much of the remaining habitat is in poor condition

[[Page 8106]]

and heavily affected by human use (U.S. Department of Interior 1994; 
Almand and Krohn 1978). Local extinctions and low colonization rates 
have also been identified as factors, and pesticides and loss of 
wintering habitat as potential factors (Hughes 1999).
    We reviewed the petition, supporting documentation, and other 
information available in our files to determine if substantial 
information is available to indicate that the requested actions may be 
warranted. We find that the petition presents substantial information 
indicating that listing a western yellow-billed cuckoo subspecies 
(Coccyzus americanus occidentalis) may be warranted, although the 
taxonomy of this subspecies is currently unclear. The petitioners 
stated that ``all existing scientific data supports the AOU conclusion 
that the western yellow-billed cuckoo is a valid sub-species.'' 
However, this statement does not represent the AOU's current position. 
The AOU does not have a current position on the validity of yellow-
billed cuckoo subspecies and has stated the need to evaluate the 
taxonomic standing of the subspecies of North American birds (AOU 
1998). The AOU's Committee on Classification and Nomenclature (the body 
that makes taxonomic decisions for North American birds) has begun a 
comprehensive review of the taxonomic status of subspecies for North 
American birds, a task that is expected to take at least several years 
(Richard C. Banks, U.S. National Museum of Natural History, chair of 
AOU Committee on Classification and Nomenclature (North America), pers. 
comm., 1999). The existing scientific data, including that provided by 
the petitioners, is equivocal (of uncertain significance) on the 
taxonomic status of western yellow-billed cuckoo subspecies.
    The yellow-billed cuckoo was separated into eastern (Coccyzus 
americanus americanus) and western (Coccyzus americanus occidentalis) 
subspecies by Ridgway (1887), who cited a larger average size for birds 
from the western versus eastern United States. Several ornithologists 
who have questioned the validity of these subspecies since that time 
(Todd and Carriker 1922; Swarth 1929; Van Tyne and Sutton 1937; Bent 
1940; Monson and Phillips 1981) noted the small magnitude and 
inconsistency of differences between eastern and western cuckoos and 
the broad overlap in the size of eastern and western individuals. The 
yellow-billed cuckoo has been the subject of two taxonomic studies 
published since 1980. One study concluded that the division of yellow-
billed cuckoos into two subspecies was not supported by the 
morphological data and that all yellow-billed cuckoos in North America 
should be classified simply as C. americanus (Banks 1988, 1990). The 
second study found small but statistically significant size differences 
between western and eastern cuckoos (Franzreb and Laymon 1993). This 
study stated that the recognition of subspecies on the basis of these 
differences was equivocal (of uncertain significance) and recommended 
that the subspecies described by Ridgway (1887) be retained, pending 
further studies (Franzreb and Laymon 1993).
    The petitioners cited the above studies' findings of statistically 
significant differences in morphological measurements between western 
and eastern cuckoos, but did not provide evidence that these 
differences meet traditional or other accepted criteria for defining 
avian subspecies. Banks (1988, 1990) concluded that these differences 
were not adequate for subspecies recognition. The petition and other 
information currently available to us do not resolve this taxonomic 
question for this species. However, we are funding ongoing genetic work 
that may aid in resolving this issue. Although the available 
information does not conclusively resolve this issue, we find that the 
petition presents substantial information that leads us to conclude 
that further investigation is required, through a status review, to 
determine if listing the western yellow-billed cuckoo as a subspecies 
is warranted.
    The petitioners stated that they believed the western States 
constitute a significant portion of the species' range. However, we 
find that the petition does not provide information to support this 
statement. The petition does not provide information on the 
conservation status of the yellow-billed cuckoo outside the western 
United States and British Columbia, Canada, and the available data do 
not indicate that the species as a whole may be threatened or 
endangered in a significant portion of its range. On a gross level, the 
area of the western States within the species' historic range 
represents about 27 percent of the total area within the species' U.S. 
range. However, this number includes the entire area of States and does 
not represent the distribution or area of habitat suitable or available 
for the species. The species nests almost exclusively in riparian 
habitats in the west and occurs widely in riparian habitats in the east 
(Hughes 1999). More than 95 percent of the riparian habitat area within 
the species' U.S. range is located east of the Continental Divide, and 
less than 5 percent is located west of the divide. Further, these 
percentages overestimate the proportion of cuckoo habitat occurring 
west of the Continental Divide, as they do not account for the fact 
that, east of the divide, the cuckoo also nests in a variety of 
nonriparian habitats, including woodlands, hardwood forests, abandoned 
farmlands, fencerows, shade trees, and gardens (Hughes 1999).
    Although not specifically addressed by the petitioners, we also 
considered whether substantial information exists indicating that 
listing of the western yellow-billed cuckoo as a distinct population 
segment (DPS) as described in our 1996 Policy Regarding the Recognition 
of Distinct Vertebrate Population Segments Under the Endangered Species 
Act (61 FR 4721) may be warranted. The policy states that we will 
consider three elements in decisions regarding the status of a possible 
DPS as endangered or threatened under the Act: (1) Distinctness of a 
population segment in relation to the remainder of the species to which 
it belongs, (2) significance of the population segment in relation to 
the species as a whole, and (3) conservation status of the population 
segment in relation to the Act's standards for listing as threatened or 
endangered. Criteria for all three elements must be satisfied to be 
considered a DPS.
    Anecdotal reports have suggested differences between eastern and 
western birds based on bill color and vocalizations (Franzreb and 
Laymon 1993), but these differences have not been documented. Western 
cuckoos have been reported to nest later, on average, than eastern 
cuckoos (Franzreb and Laymon 1993; Hughes 1999), but the species 
demonstrates considerable plasticity in timing of nesting (Hamilton and 
Hamilton 1965; Hughes 1999). These observed differences could represent 
distinct populations with genetically based adaptations to local 
conditions, however, equally plausible alternative explanations exist. 
For example, the observed differences could also represent the 
interaction between individuals of a relatively uniform but flexible 
species and local environmental factors. We are not currently aware of 
any study that has tested the alternative explanations, although the 
principal study of nesting biology published in a scientific journal 
(Hamilton and Hamilton 1965) favored the latter interpretation 
(differences are due to interactions of individuals of a flexible 
species). This study questioned whether eastern and western cuckoos 
were distinct, based on observations of

[[Page 8107]]

ecology, adaptation to the physical environment, and timing and 
duration of breeding season. Based on the available scientific 
information, it is unclear that eastern and western yellow-billed 
cuckoos are distinct. However, we find that the petition presents 
substantial information that leads us to conclude that further 
investigation is required, through a status review, to determine if 
listing the western yellow-billed cuckoo as a distinct population 
segment may be warranted.
    In making these findings, we recognize that yellow-billed cuckoo 
populations have declined in portions of their range in the United 
States, particularly west of the Continental Divide. Loss and 
degradation of western riparian habitats appears to be a primary factor 
in these declines. The range of the species has contracted 
substantially in many regions of the western United States, compared to 
the range reported for the species in the first several decades of the 
twentieth century (Gaines and Laymon 1984; Laymon and Halterman 1987; 
Hughes 1999). Population numbers have also declined substantially in 
the western United States (Hughes 1999), although scientific data on 
the magnitude of population changes are unavailable for most regions.

Public Information Solicited

    We solicit information regarding the taxonomic status, occurrence, 
and distribution of the species, and any additional data or scientific 
information from the public, scientific community, Tribal, local, 
State, and Federal governments, and other interested parties concerning 
the status of the yellow-billed cuckoo. Of particular interest is 
information regarding:
    (1) The taxonomy and genetics of the species and whether this 
information supports classifying the western yellow-billed cuckoo as a 
valid subspecies;
    (2) Behavioral and ecological differences between eastern and 
western yellow-billed cuckoos; and
    (3) Significance of the western population in relation to the 
species as a whole that may aid in differentiating population segments.
    After consideration of additional information received during the 
public information collection period (see DATES section of this 
notice), we will prepare a 12-month finding as to whether listing the 
yellow-billed cuckoo as a species, subspecies, or distinct population 
segment is warranted.

References Cited

    You may request a complete list of all references we cited, as well 
as others, from the Sacramento Fish and Wildlife Office (see ADDRESSES 
    Authority. The authority for this action is the Endangered Species 
Act of 1973, as amended (16 U.S.C. 1531 et seq.).

    Dated: February 7, 2000.
Jamie Rappaport Clark,
Director, U.S. Fish and Wildlife Service.
[FR Doc. 00-3652 Filed 2-16-00; 8:45 am]