Peer
Review Administered by
Society for Conservation Biology
Long-billed Curlew (Numenius americanus):
A Technical Conservation Assessment
Prepared for the USDA Forest Service,
Rocky Mountain Region,
Species Conservation Project
December 12, 2006
James A. Sedgwick
Ecosphere Ecological Services
2243 Main Ave, Suite 4
Durango, CO 81301
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Sedgwick, J.A. (2006, December 12). Long-billed Curlew (Numenius americanus): a technical conservation
assessment. [Online]. USDA Forest Service, Rocky Mountain Region. Available:
http://www.fs.fed.us/r2/
projects/scp/assessments/longbilledcurlew.pdf
[date of access].
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CKNOWLEDGMENTS
Ecosphere Environmental Services wishes to thank Gary Patton for the opportunity to participate in the
USDA Forest Service Species Conservation Project. The technical assistance and constructive comments of Lynn
Wickersham were instrumental in the completion of the manuscript. Numerous private organizations, federal agencies,
and biologists volunteered their time and shared their unpublished data. Special thanks to Gary Patton, Mark Colwell,
and an anonymous reviewer for valuable advice and comments on earlier drafts of this document.
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UTHOR’S
B
IOGRAPHY
James A. Sedgwick received his M.A. in zoology from the University of Montana for a comparative study of
the breeding ecology of Hammond’s and dusky flycatchers and his Ph.D. in wildlife biology from Colorado State
University. His dissertation research was on avian habitat relationships in a pinyon-juniper woodland. Currently a
Research Biologist for the U.S. Geological Survey, he has continued studies of Empidonax flycatchers, with emphasis
on geographic variation in song, lifetime reproductive success, population dynamics, and site and mate fidelity. His
other research has included studies of avian response to grazing, habitat relationships of cavity-nesting birds, and
phytosociology and demography of cottonwoods. Current address: USGS, Fort Collins Science Center, 2150 Centre
Avenue, Fort Collins, CO 80525-8118. E-mail: Empidonaxj@netzero.com.
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OVER
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HOTO
C
REDIT
Long-billed curlew (Numenius americanus). © B. L. Sullivan. Used with permission.
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S
UMMARY OF
K
EY
C
OMPONENTS FOR
C
ONSERVATION OF
L
ONG-BILLED
C
URLEW
Status
The long-billed curlew (Numenius americanus) is a locally common breeding bird of the shortgrass and
mixed-grass prairies of the Great Plains. It breeds in the following USDA Forest Service-administered units
in Region 2: Comanche National Grassland, Colorado; Cimarron National Grassland, Kansas; Oglala National
Grassland, Nebraska; and Buffalo Gap National Grassland, South Dakota. The species winters to the south of
Region 2. There is no accurate estimate of the current population size, but the species is considered vulnerable
throughout its range. Continent-wide, it has been declining at 1.6 percent per year (P = 0.08; 1966–2004Breeding
Bird Survey [BBS]). The greatest declines, however, occurred long before the initiation of the BBS, and they
were due to over harvest (1850 to 1917) and elimination of breeding habitat. Various state, federal, and private
conservation organizations have ranked the long-billed curlew as a grassland “species of concern,” “priority,” “in
need of conservation action,” or “imperiled.”
Primary Threats
Loss of native mixed-grass and shortgrass prairie to agriculture and development on breeding and wintering
grounds is the greatest threat to the long-billed curlew. Although most rangeland loss to agriculture was historical,
more recent losses are not insignificant. In Colorado, for example, 3.8 percent of the shortgrass and mixed-grass
prairie east of the Rocky Mountains was lost to agriculture and urban expansion from 1982 to 1997. The associated
negative impacts of disturbance and fragmentation also pose a threat to long-billed curlews. Increasing recreational
activity and the use of pesticides are somewhat lesser threats. Also, any absolute changes in first-year survival or
fertility rates will have major impacts on population dynamics.
Primary Conservation Elements, Management Implications and Considerations
While heavy grazing can be detrimental on arid grasslands, in the more mesic northern parts of its range the
long-billed curlew may require moderate to heavy grazing to maintain habitat condition. Prescribed burns may
be necessary in some areas to maintain the stature of breeding habitat and to reflect the historic spatial extent and
temporal pattern of prairie wildfires. A major conservation issue in the 21
st
Century, especially in Region 2, will be
managing and mitigating the negative impacts of rapidly increasing oil and gas development.