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and the Audubon Christmas Bird Count (CBC). The
BBS (http:www.mbr-pwrc.usgs.gov/bbb/intro00.html),
which started in 1966, is a nationwide (including
southern Canada) effort of over 3,500 roadside avian
surveys conducted during the breeding season. The main
objective of the BBS is to estimate long-term trends in
avian populations. The CBC began in 1900, and today,
it includes over 1,900 nationwide counts. CBCs are all-
day censuses of early-winter birds designed to monitor
status, distribution, and trends of early-winter birds
across the Americas.
Enforcement of existing laws and regulations
Enforcement of existing laws and regulations
appears to be adequate. No management efforts are
currently directed specifically at long-billed curlews on
the breeding or wintering grounds; efforts are usually
focused on grassland or wetland habitat in general.
On the Pawnee National Grassland, for example,
“intensive and extensive” monitoring of management
indicator species began in 1997 by the USFS. This
includes USFS data collection and cooperative research
agreements with Colorado State University, USFWS,
Colorado Natural Heritage Program, and Rocky
Mountain Bird Observatory. Ongoing prescribed burns
on the grassland may reduce the shrub component and
thus benefit long-billed curlews. Additionally, public
access has been restricted during vulnerable seasons
to eliminate disturbance to threatened and endangered
species, including the mountain plover (Charadrius
montanus); this should have also benefited long-billed
curlews. Road closures to improve wildlife habitat
have not been effective, however, due to budgetary
constraints. Condition and long-term health of grazing
allotments are monitored, and adjustments are made
as needed.
In Wyoming, the Thunder Basin Land and
Resource Management Plan includes two key objectives
pertinent to long-billed curlew conservation: 1)
ensuring long-term grassland health, and 2) maintaining
and enhancing the viability of native plant and animal
species. Specifically, grazing is varied, with a broad
resource emphasis, range vegetation emphasis, and
natural-appearing-landscape emphasis; few to no prairie
dog (Cynomys spp.) areas are controlled with pesticides;
certain prairie dog complexes are managed for black-
footed ferret (Mustela nigripes) reintroductions; some
areas are protected for research, education, biological
diversity, and wilderness; and off-road travel is
restricted. To minimize the effects of oil and gas
activities on the Thunder Basin National Grassland,
required mitigation includes noise limits on oil and gas
production facilities, distance restrictions from certain
vegetation types of concern, minimizing drill site traffic
and vegetation disturbance, and reclamation of the
production sites.
USFS challenges on shortgrass and mixed-grass
prairies include:
v
an increasing urban population and its
accompanying desire for recreation,
conflicting with livestock grazing on range
allotments
v
incomplete inventories of roads and trails,
which limit knowledge related to grassland
fragmentation issues
v
maintaining species viability
v
dealing with the increasing impact of oil and
gas drilling activities
v
managing for desired plant species
composition, structure, and pattern in
grasslands
v
monitoring for plant, animal, and ecosystem
processes
and functions
v
maintaining sustainable community relation-
ships
and ecosystem functions
v
managing grazing to achieve desired
vegetative conditions.
Biology and Ecology
Systematics and species description
The long-billed curlew (family Scolopacidae) is
the largest North American shorebird. It is long-legged
and has a long, decurved bill; body length is 500 to 650
mm, bill length is 113 to 219 mm, wingspread is 257 to
308 mm, tarsus is 72 to 92 mm, and tail is 104 to 136
mm (Dugger and Dugger 2002). On average, females
are larger and have longer bills, but the sexes are similar
in appearance. Plumages are similar throughout the
year; body plumage is buff tinged with cinnamon or
pink, upper parts are streaked and barred with dark
brown, underwing lining is a contrasting cinnamon,
and upper surface of remiges is orange-brown (Sibley
2000). This species’ large size and long, decurved bill
distinguish it from all other shorebirds, although the bill
may be relatively short in some males and juveniles.
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The species is monotypic following Hellmayr
and Conover (1948), Bull (1985), and Patton et al.
(2003), but some authorities recognize two subspecies
(Bishop 1910, American Ornithologists’ Union 1957,
Blake 1977). Birds of northern and western populations
(e.g., western Canada, Washington, Oregon; Numenius
americanus parvus) are smaller with shorter bills
while those of central U.S. breeding populations (e.g.,
Wyoming, Utah, Nebraska, Colorado; N. a. americanus)
are larger with longer bills; average differences in size
broadly overlap.
Distribution and abundance
The distribution of long-billed curlew breeding
populations is disjunct, corresponding to the now
fragmented distribution of the shortgrass and mixed-
grass prairies of the Great Plains, Great Basin, and
intermontane valleys of the western United States and
southwestern Canada. Long-billed curlews breed from
southern British Columbia, Alberta, and Saskatchewan,
south to northeastern New Mexico, central Nevada, and
northern Utah, and east to southwestern North Dakota
and central South Dakota and Nebraska (Figure 2;
American Ornithologists’ Union 1998, Dugger and
Dugger 2002). Long-billed curlews breed east of the
Cascades in Washington and Oregon, in northeastern
California and southern Idaho, east of the Rockies
in Montana, and in Wyoming and eastern Colorado.
The species is most numerous (breeding) in the BBS
Columbia Plateau region (southern Idaho) and the
Dissected Rockies (southwestern Montana) (Figure 2;
Sauer et al. 2005).
The total population estimate for long-billed
curlews is around 20,000 (thought to be accurate to
± 50%; Brown et al. 2000), but no comprehensive
survey has been conducted. Ground surveys of Pacific
coastal habitats (n = 3 years) in winter found 4 percent
of curlews along the Oregon and Washington coasts, 9
percent in California north of San Francisco Bay, 49
percent in San Francisco Bay, and 38 percent between
San Francisco Bay and the U.S.-Mexico border. Mean
peak abundance at 56 sites from November through
January was 3,000 individuals (CV = 20.1 percent;
Page et al. 1999). Winter surveys of inland, shallow-
water wetlands in California’s Central Valley averaged
4,786 (n = 3 years; Shuford et al. 1998). (Numbers
from coastal and inland sites are not additive; survey
times were staggered, and some movement of curlews
from coast to interior may have occurred; Shuford et al.
1998.) As many as 7,500 curlews winter in the Imperial
Valley, California (Brown et al. 2000), and perhaps
as many as 3,000 winter on the west coast of Baja
California (Page et al. 1997).
Within Region 2, the state with the highest
average relative abundance of long-billed curlews is
Nebraska, with 2.07 individuals per route (BBS survey
data; Sauer et al. 2005). Survey-wide, the average
relative abundance of long-billed curlews was 1.39
individuals per route. Densities vary from 5.94 to 6.42
Figure 2. Relative breeding season distribution and abundance (average number of birds per route) of long-billed
curlew based on Breeding Bird Survey data from 1966 to 2004.