Status assessment and conservation action plan for the long-billed curlew (numenius americanus) Biological Technical Publication BTP-R6012-2009

              U.S. Fish & Wildlife Service
Status Assessment and
Conservation Action Plan
for the Long-billed Curlew
(Numenius americanus)
Biological Technical Publication
BTP-R6012-2009
Bob Gress©
U.S. Fish & Wildlife Service
Status Assessment and
Conservation Action Plan
for the Long-billed Curlew
(Numenius americanus)
Biological Technical Publication
BTP-R6012-2009
Suzanne D. Fellows
Stephanie L. Jones
U.S. Fish and Wildlife Service, Region 6,
Nongame Migratory Bird Coordinator’s Office, Denver, CO
Cover image: Long-billed Curlew
Photo credit: Bob Gress©
ii Status Assessment and Conservation Action Plan for the Long-billed Curlew (Numenius americanus)
Author contact information:
Suzanne D. Fellows
U.S. Fish and Wildlife Service, Region 6
Nongame Migratory Birds
P. O. Box 25486 DFC
Denver, CO 80225-0486
Phone: 303-236-4417
Email: Suzanne_Fellows@fws.gov
Stephanie L. Jones
U.S. Fish and Wildlife Service, Region 6
Nongame Migratory Birds
P. O. Box 25486 DFC
Denver, CO 80225-0486
Phone: 303-236-4409
Email: Stephanie_Jones@fws.gov
For additional copies or information, contact:
U.S. Fish and Wildlife Service, Region 6
Nongame Migratory Birds
P. O. Box 25486 DFC
Denver, CO 80225-0486
Recommended citation:
Fellows, S. D., and S. L. Jones. 2009. Status
assessment and conservation action plan for the
Long-billed Curlew (Numenius americanus). U.S.
Department of Interior, Fish and Wildlife Service,
Biological Technical Publication, FWS/BTP-R6012-
2009, Washington, D.C.
Table of Contents iii
Table of Contents
List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
List of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi
Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii
Chapter 1: Status Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Taxonomy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Legal Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
United States. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Canada. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
México.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Breeding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Migration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Wintering. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Population Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Conservation Status. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Population Numbers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Population Trends. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Habitat Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Breeding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
	 Water . 8
	 Habitat block size. 9
	 Vegetation structure during nesting. 9
	 Vegetation structure during brood rearing. 9
Winter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
	
Migration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Threats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Over-utilization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Habitat Loss. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Predation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Grazing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Energy Development. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Disease. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Pesticides. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Other. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
	 Vehicles. 12
	 Disturbance. 12
Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
iv Status Assessment and Conservation Action Plan for the Long-billed Curlew (Numenius americanus)
Chapter 2: Conservation Action Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Priority Actions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Population Monitoring and Assessment .  . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Migration Staging and Wintering Areas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Habitat Assessment and Management. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Research .  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
	Education and Outreach. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Other Species Covered. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Priority Populations and Regions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Conservation Strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Completed and On-going Conservation Actions. . . . . . . . . . . . . . . . . . . . . . . . . . 21
Chapter 3: State and Provincial Summaries of Long-billed Curlew Status . . . . . . . . . . . . . . 22
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
United States. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Arizona. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
California. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Colorado. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Idaho. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Kansas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Montana. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Nebraska. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Nevada. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
New Mexico. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
North Dakota .  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Oklahoma. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Oregon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
South Dakota. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Texas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Utah. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Washington .  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Wyoming .  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Alabama, Florida, Georgia, Louisiana, Mississippi, North Carolina, and South Carolina. . . . . . . . 57
Illinois, Indiana, Iowa, Michigan, Minnesota, and Wisconsin. . . . . . . . . . . . . . . . . . . . 59
Canada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Alberta . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
British Columbia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Saskatchewan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
México . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Baja California . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Baja California Sur . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Chihuahua. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Coahuila. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Colima .  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Jalisco. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Nayarit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Nuevo León. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
Sinaloa .  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Sonora .  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Tamaulipas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Veracruz. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Literature Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
v
List of Figures
Figure 1.1. Current breeding and wintering range of Long-billed Curlews (Numenius americanus). . . . . .1
Figure 1.2. Historic breeding range of Long-billed Curlews (Numenius americanus) in the midwestern
portion of the U.S. and Canada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Figure 1.3. Breeding Bird Survey abundance map (1994–2003; Sauer et al. 2008) . . . . . . . . . . . . . 7
Figure 1.4. Breeding Bird Survey trend map (1966–2003; Sauer et al. 2008) . . . . . . . . . . . . . . . 8
Figure 3.1. Christmas Bird Count data for the California region for 2002-2003 (National Audubon Society
2006) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Figure 3.2. Breeding locations (lat-long) for Long-billed Curlews in Idaho. Period of presence is March-
November (migration and breeding; R. Sallabanks, pers. comm.) . . . . . . . . . . . . . . . . . . . 29
Figure 3.3. Map of Montana QLL (quarter-latilong) for Long-billed Curlews. Records are displayed by
latilongs or mapping units formed by successive lines of latitude and longitude, marked at one-degree
intervals. Latilongs are numbered, their quarter-latilongs are divided into A, B, C, D
(Lenard et al. 2003) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Figure 3.4. Hypothetical current breeding distribution and relative abundance of Long-billed Curlews
in Nebraska using interpolated (inverse-distance weighted) BBS data. Range limits were determined
using known occurrences from previously-mentioned sources and the boundaries of ecoregions where
large tracts of suitable habitat remain and where Long-billed Curlews have been observed. Relative
abundance was determined by interpolating (inverse-distance weighted) BBS data to produce a
continuous spatial layer. The interpolated layer was then clipped to the ecoregions considered suitable.
Darker shades indicate areas of greater abundance. Question marks indicate areas where occurrence
is problematic (Jorgensen 2006) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Figure 3.5. Historic (prior to 2005) and current (2005-2006) Long-billed Curlew locations in North Dakota
(Ackerman 2007) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Figure 3.6. Locations of Long-billed Curlews reported during the Oklahoma Breeding Bird Atlas (Smith
2004). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Figure 3.7. Location of breeding Long-billed Curlews in Texas (Seyffert 2001b). . . . . . . . . . . . . . 48
Figure 3.8. Utah Long-billed Curlew breeding habitat (Utah Division of Wildlife Resources 1999) . . . . . 51
Figure 3.9. Distribution of Long-billed Curlews in Jalisco (S. Hernández-Vásquez and F. G. Cupul
Magaña, pers. comm.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Figure 3.10. Total and standardized abundance (individuals per hour of survey) of Long-billed Curlews
during Christmas Bird Counts in Puerto Peñasco, Sonora (M. M. Gómez-Sapiens, O. Hinojosa-Huerta,
and E. Soto-Montoya, pers. comm.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Figure 3.11. Number of Long-billed Curlews in the Golfo de Santa Clara and Isla Montague, Sonora
during 2004–2006. In 2004, average number (SE) of curlews per month in two transects of 1 km long.
In 2005 and 2006, three transects in the Golfo de Santa Clara and two transects in Isla Montague
(M. M. Gómez-Sapiens, O. Hinojosa-Huerta, and E. Soto-Montoya, pers. comm.) . . . . . . . . . . . . . . . . . . . . . . 79
Figure 3.12. Number of Long-billed Curlews in two transects (5 counting points–400 m between points)
in Bahía Adahír (Puerto Peñasco), Sonora from December 2005 to May 2006 (M. M. Gómez-Sapiens, O.
Hinojosa-Huerta, and E. Soto-Montoya, pers. comm.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Figure 3.13. Records of Long-billed Curlews in Tamaulipas (Garza-Torres 2006) . . . . . . . . . . . . . . . . . . . . . . . . 81
List of Figures
vi Status Assessment and Conservation Action Plan for the Long-billed Curlew (Numenius americanus)
Table 1.1. State, Provincial, and Natural Heritage status, season of presence, and relative abundance of
Long-billed Curlews in Canada, México, and U.S. . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Table 1.2. Primary Long-billed Curlew range, numbers, and physiographic divisions (Jones et al. 2008).
Primary breeding areas are divided into Bird Conservation Regions (BCRs). . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Table 2.1. Recommended prioritized conservation actions for Long-billed Curlews (LBCU) throughout
their range. This list serves to identify conservation action items that could lead to the conservation of this
species. Where “Lead party” has been identified it is not meant to obligate any party to provide funding or
implement the action. In a few cases, potential partners and costs have been identified; in most cases that
needs to be completed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Table 3.1. Location and number of Long-billed Curlew pairs found in Oregon. . . . . . . . . . . . . . . 43
Table 3.2. Density of Long-billed Curlew territories in different breeding areas in Washington.
Note that the two sites with highest densities are on small islands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Table 3.3. Abundance of Long-billed Curlews by site in Jalisco . . . . . . . . . . . . . . . . . . . . 73
Table 3.4. Geographic coordinates of records Long-billed Curlews in Tamaulipas (Garza-Torres 2006) . . . . . 82
List of Tables
vii
The historical breeding range of Long-billed
Curlews (Numenius americanus) was the western
U.S. and the southern Canadian Prairie Provinces
from California north to British Columbia and east
to southern Manitoba and Wisconsin, northern
Iowa and eastern Kansas. However, this breeding
distribution has contracted and Long-billed Curlews
have lost about 30% of their historical range. The
eastern edge of the current breeding range is the
western Great Plains from the Texas panhandle
north throughout southwestern and south central
Saskatchewan. Long-billed Curlews currently
winter along the southwestern U.S. coast from
central California, southern Texas and Louisiana
south along both of México’s coasts to Guatemala,
and are casual along the Atlantic coast north to New
Brunswick, the southeastern South Carolina and
Florida coasts, and the West Indies.
Long-billed Curlews are federally protected in the
U.S., Canada, and México under the Migratory
Bird Treaty Act. In the U.S., they are listed as a
U.S. Fish and Wildlife Service Bird of Conservation
Concern: nationally, in five U.S. Fish and Wildlife
Service regions, and in several Bird Conservation
Regions. They are listed as a species of concern in
several U.S. states. In Canada, they are on Schedule
1 of the Species at Risk Act as a “Species of Special
Concern” and are “Blue Listed” in Alberta and
British Columbia. In addition, they are listed as
“Highly Imperiled” in both the U.S. and Canadian
shorebird conservation plans. Long-billed Curlews
are a protected migratory bird species but do not
have an official conservation designation in México.
The high levels of concern are due to the loss of the
eastern third of their historical breeding range and
apparent population declines, particularly in the
shortgrass and mixed-grass prairies of the western
Great Plains. The Breeding Bird Survey (BBS)
does not show any significant trends for Long-billed
Curlews throughout much of their range; however,
the applicability of BBS to adequately monitor Long-billed
Curlews has been questioned. Documented
declines have occurred in several portions of their
range, including historical population declines, the
contraction of breeding range, and reductions in the
number of migrants along the Atlantic coast. Initial
population declines were attributed to over-hunting
and plowing of the native prairies for agriculture.
Current threats include habitat loss and destruction
due to urban development, grassland conversion for
agricultural purposes, changes in the natural fire
regime and the spread of exotic invasive species.
Predation, grazing practices, energy development,
diseases, and pesticides may also threaten Long-billed
Curlew populations.
Long-billed Curlews breed, migrate, and winter
across multiple geographical ranges; therefore,
effective conservation actions will require
cooperation by local, regional, and international
entities. Several important steps have been taken
towards identifying limiting factors affecting Long-billed
Curlew populations. Current conservation
needs include: population monitoring, breeding
ground studies that identify local micro-habitat use,
and identification of critical wintering and migration
areas. The development and use of management
recommendations for maintaining native grasslands,
invasive species control, and water and wetland
conservation are also important to the maintenance
of Long-billed Curlew populations. Investigation of
the effects of energy development and subsequent
operations is increasingly important as the demand
for alternative “green” energy sources increases.
Public outreach will continue to be an important
tool in the conservation of Long-billed Curlew
populations. Currently, while there are very few
specific Long-billed Curlew management and
conservation projects on-going, there are many
identified needs.
This status assessment and conservation action plan
is intended to be a summary of the current state
of the species, and a guide to its conservation. It
is organized into three chapters. The first chapter
gives the general information needed to understand
the current status of Long-billed Curlews, with
a focus on current threats and management
requirements. The second chapter is the
conservation action plan. The third chapter outlines
the status of Long-billed Curlews in the states and
provinces where they occur, throughout the U.S.,
Canada, and México.
Executive Summary
viii Status Assessment and Conservation Action Plan for the Long-billed Curlew (Numenius americanus)
Many individuals contributed significant time,
unpublished literature, and expertise to the
development of this Status Assessment and
Conservation Action Plan including: Brad A. Andres,
Thomas R. Cooper, Guillermo Fernández, Cheri L.
Gratto-Trevor, William H. Howe, Christopher M.
Rustay, Robert P. Russell, and Susan M. Thomas.
State and provincial summaries were written
by Alfonso Banda-Valdez, Joseph B. Buchanan,
J. Nan Clarke, Miguel A. Cruz Nieto, Fabio G.
Cupul-Magaña, Guillermo Fernández, Daniel
Galindo-Espinosa, Martha M. Gómez-Sapiens,
José I. Gonzales-Rojas, Cheri L. Gratto-Trevor,
Sandra H. Johnson, Salvador Hernández-Vázquez,
Catherine M. Hickey, Osvel Hinojosas-Huerta,
William H. Howe, Kent C. Jensen, Armando
Jiménez-Camacho, Joel G. Jorgensen, David S.
Klute, David J. Krueper, Stefani L. Melvin, Gary
W. Page, Allison J. Puchniak, Gabriel Ruiz-Ayma,
Robert P. Russell, Irene Ruvalcaba-Ortega, Rex
Sallabanks, W. David Shuford, Eduardo Soto-
Montoya, Elisa Peresbabosa-Rojas, Susan M.
Thomas, and Brad Winn.
Western Hemisphere Shorebird Reserve Network
has been instrumental in coordinating the
development of shorebird species plans which
highlight site-specific conservation actions. In
keeping with this goal, Guillermo Fernández
coordinated the effort in México to develop and
provide accounts for several states. We greatly
appreciate his efforts and Manomet Center for
Conservation Sciences for allowing us to incorporate
this information in state summaries for this
document.
We are grateful to the many reviewers, whose
comments improved this status assessment and
state and provincial summaries including Daniel S.
Ackerman, Brad A. Andres, Doug Backlund, William
H. Busby, Andrea Orabona, Mark A. Colwell, Troy
E. Corman, Helen M. Hands, C. Alex Hartman,
William H. Howe, Mark Howery, Kevin J. Kritz,
Stefani L. Melvin, Larry A. Neel, Eric A. Odell,
Lewis W. Oring, Thomas G. Shane, Julie A. Steciw,
Heather C. Tipton, Sartor O. Williams III, and
Eugene A. Young.
Figure 1.1 was provided by Michael Artmann, U.S.
Fish and Wildlife Service, Figure 1.2 was provided
by Thomas R. Cooper, U.S. Fish and Wildlife
Service. Thanks to Bob Gress and Cory Gregory for
use of their photos.
Acknowledgments
1
Taxomony
Two subspecies of Long-billed Curlew (Numenius
americanus) have been identified in North America;
however Grinnell (1921) disputes this.
Class: Aves
Order: Charadriiformes
Family: Scolopacidae
Subfamily: Tringinae
Tribe: Numeniini
Genus: Numenius
Species: americanus
Supspecies: N. a. americanus, N. a. parvus
Authority: (Bechstein, Subspp. Bishop)
Numenius americanus americanus Bechstein
1812 is reportedly larger and has a more southerly
breeding range in the western through central U.S.
than N. a. parvus. The breeding range encompasses
northeastern Nevada east through southern Idaho,
central Utah, southern Wyoming, and southern
South Dakota, south to central New Mexico and
central southern Texas (Fig. 1.1). N. a. americanus
was historically also found as far east as southern
Wisconsin, northern Iowa, and eastern Kansas
(Fig. 1.2) but is no longer found breeding east of
central Kansas or east of the Missouri river in
eastern North and South Dakota. N. a. americanus
winters primarily along the southwestern U.S.
coast from central California, southern Texas and
Louisiana, and south along both of México’s coasts
to Guatemala. It is casual along the Atlantic coast as
far north as New Brunswick, along the southeastern
South Carolina and Florida coasts, and in the West
Indies (American Ornithologists’ Union 1957, 1998;
del Hoyo et al. 1996; Dugger and Dugger 2002).
N. a. parvus Bishop 1910 (also known as N. a.
occidentalis) is smaller, breeding in the northern
part of the range. It historically bred from south
central British Columbia east through southern
Alberta and Saskatchewan to southern Manitoba
and south to northeastern California, central
Chapter 1: Status Assessment
Chapter 1: Status Assessment
Figure 1.1. Current breeding and wintering range of Long-billed Curlews (Numenius americanus).
0 280 560 Miles
Legend
Current Breeding Distribution
Limits of Former Breeding Range
Current Wintering Distribution
Limits of Former Wintering Range
2 Status Assessment and Conservation Action Plan for the Long-billed Curlew (Numenius americanus)
western Nevada, northern Idaho, southwestern
Montana, eastern North Dakota, central Wyoming,
and northwestern South Dakota. It is no longer
found in eastern North Dakota or in Manitoba (Fig.
1.2). It winters primarily in the southwestern U.S.
from California and Louisiana south to central-southern
México (American Ornithologists’ Union
1957, 1998; del Hoyo et al. 1996; Dugger and Dugger
2002; Fig. 1.1).
Numenius longirostra(is) was used until about 1900
as a synonym for the species (Blachly 1880, Dugger
and Dugger 2002). Common names that have been
used include Sickle Bill (Sicklebill or Sickle-billed
Curlew), the French Courlis à long bec and the
Spanish Zarapito Americano, (del Hoyo et al. 1996,
Committee on the Status of Endangered Wildlife in
Canada 2002, Dugger and Dugger 2002).
This report will address the two subspecies together
since they are not well defined by either range or
appearance (Grinnell 1921, Dugger and Dugger
2002).
Legal Status
Long-billed Curlews (curlews) are federally
protected in the U.S., Canada and México under
the Migratory Bird Treaty Act of 1918 as amended
(16 U.S.C. 703-711: 40 Stat. 755; U.S. Fish and
Wildlife Service 2008a). They are not listed on the
Convention on International Trade in Endangered
Species list (Inskipp and Gillett 2005).
United States
Long-billed Curlews are not federally listed under
the Endangered Species Act as amended (U.S.
Fish and Wildlife Service 2008b); they are listed as
Endangered, Threatened, or as a species of concern
in several states (Table 1.1; also see Chapter 3, page
22).
Canada
The Committee on the Status of Endangered
Wildlife in Canada first designated Long-billed
Curlews as a species of Special Concern in 1992
and re-examined and reconfirmed this designation
in 2002 (Committee on the Status of Endangered
Wildlife 2002). In 2004 they were added to Schedule
1 of the Species at Risk Act as a Species of Special
Concern (Environment Canada 2004). Long-billed
Curlews are “Blue Listed” (provincial species of
special concern due to sensitivity to human activities
and natural events) in Alberta (Hill 1998) and
British Columbia (Cannings 1999). They have been
extirpated in Manitoba (Committee on the Status of
Endangered Wildlife 2002).
México
Although Long-billed Curlews are a protected
migratory bird species, they do not have an official
conservation designation in México (Secretaria de
Medio Ambiente y Recursos Naturales 2002).
Figure 1.2. Historic breeding range of Long-billed Curlews (Numenius americanus) in the midwestern
portion of the U.S. and Canada.
Chapter 1: Status Assessment 3
Table 1.1. State, Provincial, and Natural Heritage status, season of presence, and relative abundance of Long-billed
Curlews in Canada, Mexico, and U.S.
Location State/Provincial Natural Heritage Season of Abundance 4
Status 1 Status 2 Presence 3
Canada COSEWIC: Special Concern N4B
	
Alberta Blue List S3 b, m b: abundant; m: common
British Columbia Blue List S3B b, m, w b: uncommon; m: uncommon;
	
			 w: rare
Manitoba S/P: none SXB, SAN m b: extirpated; m: rare
Saskatchewan S/P: none S4B, S4M b, m b: common; m: uncommon
	
	
	
	
México None
	
	
Baja California S/P: none Not Ranked m, w m: common; w: common
Baja California Sur S/P: none Not Ranked m, w, o m: common; w: common;
			 o: uncommon
Chiapas S/P: none Not Ranked m, w sporadic
Chihuahua S/P: none Not Ranked m, w, o m: common; w: common;
			 o: uncommon
Coahuila S/P: none Not Ranked m, w, o m: abundant; w: common;
			 o: uncommon
Colima S/P: none Not Ranked m, w m: uncommon; w: uncommon
Distrito Federal S/P: none Not Ranked m, w sporadic
Durango S/P: none Not Ranked m, w sporadic
Guanajuato S/P: none Not Ranked m, w sporadic
Guerrero S/P: none Not Ranked m, w sporadic
Jalisco S/P: none Not Ranked m, w m: uncommon; w: uncommon
Morelos S/P: none Not Ranked m, w sporadic
Nayarit S/P: none Not Ranked m, w m: uncommon; w: common
Nuevo León S/P: none Not Ranked m, w m: common; w: abundant
Oaxaca S/P: none Not Ranked m, w sporadic
Querétaro S/P: none Not Ranked m, w sporadic
Quintana Roo S/P: none Not Ranked m, w sporadic
Sinaloa S/P: none Not Ranked m, w, o m: common; w: common;
			 o: uncommon
Sonora S/P: none Not Ranked m, w, o m: common; w: uncommon;
			 o: uncommon
Tamaulipas S/P: none Not Ranked m, w m: uncommon; w: uncommon
Veracruz S/P: none Not Ranked m, w, o m: uncommon; w: uncommon;
	
			 o: uncommon
Yucatán S/P: none Not Ranked m, w sporadic
Zacatecas S/P: none Not Ranked m, w sporadic
	
	
	
	
U.S. BCC: National; R1, R2, R4, N5B, N5N
R6, R8; BCR: 5, 9, 10, 11, 17,
18, 19, 21, 32, 33, 35, 36, 37
	
	
Alabama S/P: none; BCC: R4 S2N m, w m: rare; w: rare
Arizona S/P: none; BCC: R2, BCR 33 S1B, S3/4N b, m, w b: rare; m: uncommon;
			 w: uncommon
California S/P: none; BCC: R8, BCR 5,
9, 32, 33 S2 b, m, w, o b: uncommon; m: abundant;
	
			 w: common; o: uncommon
Colorado S/P: Species of Concern; S2B b, m b: common; m: uncommon
CWCS: Tier I Species of
Greatest Conservation Need;
BCC: R6, BCR 18
	
Florida S/P: none; BCC: R4 SNA m, w m: rare, w: rare
Georgia S/P: none; CWCS: Species of
Concern; BCC: R4 S3 m, w m: rare, w: rare
Idaho S/P: none; CWCS: Species of S3B b, m b: abundant; m: NA
Greatest Conservation Need;
BCC: R1, BCR 9, 10
	
Illinois S/P: none SXB m b: extirpated; m: rare
Indiana S/P: none SNA m b: extirpated; m: rare
Iowa S/P: none; BCC: BCR 11 SXB m b: extirpated; m: rare
4 Status Assessment and Conservation Action Plan for the Long-billed Curlew (Numenius americanus)
Table 1.1. continued
Location State/Provincial Natural Heritage Season of Abundance 4
Status 1 Status 2 Presence 3
Kansas S/P: State Species in Need S1B, S2N b, m b: rare; m: common
of Conservation; BCC: R6,
BCR 18, 19
Louisiana S/P: none; BCC: R4, BCR 37 S5N m, w m: rare; w: rare
Michigan S/P: none SNA m m: rare
Minnesota S/P: none; BCC: BCR 11 SXB, SXM m b: extirpated; m: rare
Mississippi S/P: none; BCC: R4 SNA m,w m: rare; w: rare
Montana S/P: Species of Concern; S2B b, m b: abundant; m: common
CWCS: Tier I Greatest Need
Species; BCC: R6, BCR 10,
11, 17
Nebraska S/P: Natural Legacy Plan S5 b, m b: abundant; m: uncommon
Tier I At Risk Species;
BCC: R6, BCR 11, 17, 18, 19
Nevada CWCS: Species of S2, S3B b, m, w b: abundant; m: uncommon;
Conservation Priority; BCC: 		 w: rare
R8, BCR 9, 33
New Mexico CWCS: Species of Greatest S3B, S4N b, m, w b: common; m: common;
Conservation Need; BCC: 		 w: uncommon
R2, BCR 16, 18, 35
North Carolina S/P: none; BCC: R4 SNA m, w m: rare; w: rare
North Dakota S/P: Imperiled (Natural S2B b, m b: uncommon; m: uncommon
Heritage Inventory);
CWCS: Level I Species of
Conservation Priority; BCC:
R6, BCR 11, 17
Oklahoma S/P: Species of Conservation S2B b, m b: uncommon; m: common
Concern; CWCS: Species of
Greatest Conservation Need;
BCC: R2, BCR 18, 19, 21
Oregon CWCS: Vulnerable Sensitive S3B b, m, w b: abundant; m: common;
Species; BCC: R1, BCR 5, 9, 10 		 w: rare
South Carolina CWCS: Species of Highest SNA m, w m: rare; w: rare
Priority; BCC: R4
South Dakota S/P: Species of Greatest S3B b, m b: abundant; m: uncommon
Conservation Need; BCC:
R6, BCR 11, 17, 18
Texas CWCS: State Species of S3B, S5N b, m, w b: uncommon; m: common;
Concern; BCC: R2, BCR 		 w: common
18, 19, 21, 35, 36, 37
Utah S/P: Sensitive Species; S2, S3B b, m b: abundant; m: common
CWCS: Tier II; PIF: Priority
Species; BCC: R6, BCR 9
Washington S/P: Protected Wildlife; S2S3B, S2N b, m, w b: uncommon; m: uncommon;
BCC: R1, BCR 5, 9, 10 		 w: uncommon
Wisconsin S/P: none SXB m b: extirpated; m: rare
Wyoming CWCS: Species of Greatest S3B b, m b: uncommon; m: uncommon
Conservation Need, Native
Species Status 3; PIF: Level I
Priority Species; BCC: R6, BCR
10, 17, 18
1 State/Provincial Status is based on the Committee on the Status of Endangered Wildlife in Canada (COSEWIC; COSEWIC 2002); Birds of
Conservation Concern 2002 and 2008 reports (BCC; USFWS 2002, 2008c); State Comprehensive Wildlife Conservation Strategy plans (CWCS;
see Chapter 3 below); current State/Provincial designated classifications (S/P); and local Partners in Flight plans (PIF). BCC lists are further
qualified by all which apply within state boundaries: USFWS Region (R) and Bird Conservation Region (BCR).
2 NatureServe (2006) scores: Global (G), National (N), State/Provincial (S); Breeding (B), Migrating (M), Nonbreeding (N); 5 (Secure), 4
(Apparently Secure), 3 (Vulnerable), 2 (Imperiled), 1 (Critically Imperiled), X (Presumed Extirpated), and NA (Not Applicable).
3 Typical season of current presence within State/Province: breeding (b), migration (m), winter (w); in some locations nonbreeding birds are
present during the breeding season, these individuals are thought to be nonbreeding adults and/or first and second year nonbreeding birds, they
are designated as over-summering (o).
4 Abundance is based on information provided for states and provinces. Breeding (b), migration (m), winter (w), oversummering (o).
Measurements are relative to other sites currently reporting Long-billed Curlew and are based upon the following scale: rare (has been
reported in small numbers, BBS (Sauer 2008) abundance less than 0.25, population estimates or numbers are less than 100), uncommon
(population estimates or reported numbers less than 1000, localized, BBS abundance less than 0.75), common (has been reported in numbers
of less than 5000, BBS abundance less than 1.25), abundant (has been reported in numbers over 5000, BBS abundance is greater than 1.25),
extirpated, and N/A (information not currently available). For locations with rare, sporadic, extirpated, or no reported information, individual
summaries have not been included in Chapter 3.
Chapter 1: Status Assessment 5
Description
Long-billed Curlews are the largest North American
shorebird. They have a long, decurved bill and
buffy-cinnamon colored plumage. They are sexually
dimorphic, with females generally larger and with
a longer bill than males. However, there is some
overlap and the bills of juvenile birds are often
shorter as well. Body length ranges from 500-650
mm, bill length 113-219 mm, wingspread 257-308
mm, tarsus 72-92 mm and tail 104-136 mm. Similar
species include Whimbrels (Numenius phaeopus),
Bristle-thighed Curlews (N. tahitiensis), and
Marbled Godwits (Limosa fedoa). The plain crown
and larger size of Long-billed Curlews distinguishes
them from the first two species and the slightly
recurved bill of Marbled Godwits will exclude
curlews (Dugger and Dugger 2002).
Range
Breeding
Long-billed Curlews currently breed west of the
Missouri River in the Dakotas, in west-central
Nebraska, and in a few counties in southwestern
Kansas (Fig. 1.1); historically they were locally
common breeders as far east as southeastern
Wisconsin, northeastern Illinois, and southern
Manitoba (Fig. 1.2). Blanchan (1904) indicated that
historically they also nested in the south Atlantic
states, however; there are no current breeding
records from this region (American Ornithologists’
Union 1998). There are recent breeding records
from east-central Arizona and south-eastern New
México through the panhandle of Texas (American
Ornithologists’ Union 1998, NatureServe 2006).
Migration
Long-billed Curlews migrate along the Pacific
Coast and throughout the central U.S. (American
Ornithologists’ Union 1998). Historically, Long-billed
Curlews frequently occurred as far north as
Massachusetts (Allen 1937) and flocks staged on
Long Island, New York between July and September
(Blanchan 1904). Sightings along the north Atlantic
coast are now rare (Hunter 2006).
During migration, Long-billed Curlews can occur
in large numbers at roost sites, a behavior that has
been observed in Kansas (Shane 2005) and Texas
(D. S. Stolley, pers. comm.). Birds come in to the
roosts just at sunset from areas of foraging 8 to 32
km distant. In western Finney County, Kansas, an
estimated 2500 individuals landed at a single roost
area covering over 400 ha of agriculture fields on
29 March 2007. Most of the curlews had returned
to the daytime foraging areas the next morning (T.
G. Shane, pers. comm.). In Texas, records include
2261 individuals in Cameron County on 11 February
2004 (D. S. Stolley, pers. comm.). Documentation
at fall migration stopover sites has led to estimates
of at least 30,000 individuals using the interior
valleys of California (G. W. Page, W. D. Shuford,
G. M. Langham, and K. C. Molina, pers. comm.).
Estimates of the number of curlews using the Delta
del Río Colorado, Sonora, México during spring
and fall migration are approximately 2500 and 1250
individuals respectively (Mellink et al. 1997). It
is likely that there are other significant stopover
sites which have not been previously documented.
Length of stay by individuals at these stopover sites
is unknown (T. G. Shane, pers. comm.; D. S. Stolley,
pers. comm.).
Wintering
Long-billed Curlews spend the winter along
the Pacific Coast, primarily from Humboldt
Bay, California south through Central America,
throughout Baja California, along the Gulf of
México, and within the interior of northern and
central México, especially within the Mexican
Plateau (Fig. 1.1; American Ornithologists’ Union
1998, Dugger and Dugger 2002). The population
estimate of wintering birds in the Valle de la
Soledad, La Soledad Natural Protected Area, Nuevo
León, México is estimated to be 6392 individuals
(J. I. Gonzalez-Rojas, pers. comm.). Estimates for
California suggest as many as 20,000 individuals may
winter inland (G. W. Page, W. D. Shuford, and C. M.
Hickey, pers. comm.) and up to 5000 along the coast
(Page et al. 1999). Currently, about 400 birds winter
along the southeast Atlantic Coast from South
Carolina to central Florida, and occasionally as far
north as North Carolina (Hunter 2006). Larger
numbers historically wintered in this region (Allen
1937). Birds historically wintered in the West Indies,
Guatemala, Honduras, Costa Rica, and Venezuela
(Blanchan 1904, McNeil et al. 1985, NatureServe
2006) and there has been a recent sighting in Peru
(Senner 2006).
Population Status
Conservation Status
Long-billed Curlews have a Global Heritage Status
Rank of G5 (secure; NatureServe 2006). They
are a species of special concern throughout their
range in North America, with both the Canadian
and U.S. shorebird conservation plans listing it as
“Highly Imperiled” (Donaldson et al. 2000, U.S.
Shorebird Conservation Plan 2004). They are
considered one of the highest priority species for
monitoring among the shorebird species breeding
the temperate region (Bart et al. 2005). This level
of concern is due to apparent population declines,
particularly in the shortgrass and mixed-grass
prairie of the western Great Plains (Brown et al.
2001, U.S. Shorebird Conservation Plan 2004). The
trend for the population is listed as “5” (declining)
by the Canadian and U.S. shorebird conservation
plans (Donaldson et al. 2000, Brown et al. 2001, U.S.
Shorebird Conservation Plan 2004).
Long-billed Curlews are listed nationally as a
U.S. Fish and Wildlife Service (USFWS) Bird
of Conservation Concern, in USFWS Regions
6 Status Assessment and Conservation Action Plan for the Long-billed Curlew (Numenius americanus)
Table 1.2. Primary Long-billed Curlew range, numbers, and physiographic divisions (Jones et al. 2008). Areas are described by Bird Conservation Regions (BCRs).
Name Geographic locations Physiographic divisions Number (individuals)
Primary Breeding Areas
Northern Mixed-grass Prairie ne. Montana, North Dakota, South Dakota, Prairie Potholes BCR (11), Badlands and 70,000
	
Saskatchewan, Alberta Prairies BCR (17)
Shortgrass Prairie Wyoming, Colorado, Nebraska, Kansas, Shortgrass Prairie BCR (18), Southern Rockies/ 30,000
	
Oklahoma, New Mexico, Texas Colorado Plateau BCR (16)
Great Basin Utah, Nevada, s. Idaho, ne. California Great Basin BCR (9) 40,000
Columbia Basin e. Oregon, e. Washington, British Colombia, Northern Rockies BCR (10) 5,000
n. Idaho
Primary Wintering Areas
	
Atlantic Coast Florida, coastal Georgia, South Carolina, Peninsular Florida BCR (31), Southeastern Coastal 200 (estimated)
North Carolina Plain BCR (27)
Gulf Coast Texas, Louisiana, Mississippi, Alabama, Gulf Coastal Prairie BCR (37), Mississippi Alluvial Texas1: 3,000 (estimated)
	
Florida panhandle and w. peninsula Valley BCR (26), Southeastern Coastal Plains Other: 100 (estimated)
	
	 BCR (27), Peninsular Florida BCR (31)
Pacific Coast coastal British Columbia, Washington, Coastal California BCR (32), Northwestern California central valley2: 30,000
Oregon, California central valley and coast Pacific Rainforest BCR (5) Coastal 2: 20,000 (estimated)
México, Pacific3 Baja California, Baja California Sur, Desierto de Baja California BCR (40), Sonora 25,000 (estimated)
Colima, Jalisco, Nayarit, Sinaloa, coastal and Mohave Deserts BCR (33), Planicie Costera,
Sonora Lomeríos y Cañones de Occidente BCR (43),
	
	
	 Marismas Nacionales BCR (44), Planicie Costera
	 y Lomerîos del Pacífico Sur BCR (45)
	
México, Gulf3 Tamaulipas, Veracruz Gulf Coastal Prairie BCR (37) 500 (estimated)
México, Inland3 e. Sonora, Chihuahua, Coahuila, Nuevo León, Sierra Madre Occidental BCR (34), Unknown (could be 60,000)
Durango, Zacatecas, San Luis Potosí Chihuahua Desert BCR (35), Tamaulipan
	 Brushlands BCR (36)
1 B. Ortega, pers. comm., 2 PRBO data (D. Shuford, pers. comm.), 3 G. J. Fernández, pers. comm.
Chapter 1: Status Assessment 7
1 (Pacific Region, mainland only), 2 (Southwest
Region), 4 (Southeast Region), 6 (Mountain-Prairie
Region), and 8 (Pacific Southwest Region). They
are also listed in Bird Conservation Regions 5
(Northwestern Pacific Rainforest), 9 (Great Basin),
10 (Northern Rockies), 11 (Prairie Potholes), 17
(Badlands and Prairies), 18 (Short Grass Prairie),
19 (Central Mixed Grass Prairie), 21 (Oaks and
Prairies), 32 (Coastal California), 33 (Sonoran
and Mojave Deserts), 35 (Chihuahua Desert), 36
(Tamaulipas Brushlands) and 37 (Gulf Coast Prairie;
U.S. Fish and Wildlife Service 2002, 2008c).
Population Numbers
Recent work has suggested that there are
considerably more Long-billed Curlews than the
previous rangewide estimates of 20,000 (Brown et
al. 2001, Morrison et al. 2001) or 55,000 individuals
(54,873, range 32,700–62,500; SLJ). These estimates
were derived from a compilation of expert opinion
and most results were from surveys considered to
be of poor or unreliable accuracy. A later estimate
incorporating the rangewide survey coordinated by
USFWS and U.S. Geological Survey (USGS; Stanley
and Skagen 2007, Jones et al. 2008), estimated
the population at 123,500 (range 65,000–163,500;
Morrison et al. 2006). The 2004-2005 range-wide
survey followed a statistically valid design, occurred
over two years and counted breeding Long-billed
Curlews in 16 western states and three Canadian
provinces (Stanley and Skagen 2007, Jones et
al. 2008). In this survey, total curlew population
size averaged across the two years was 161,181
individuals (range 120,882-549,351; Jones et al.
2008). Estimates for the U.S. were 166,244 for
2004 and 96,276 for 2005; estimated for the three
Canadian provinces combined were 16,988 for 2004,
and 42,856 for 2005 (range 11,999-72,152 individuals;
Jones et al. 2008; Table 1.2).
Population Trends
Breeding Bird Survey (BBS) data for Long-billed
Curlews presently consists of 280 survey routes
containing curlews; 220 of these routes are in the
U.S. and 60 are in Canada. Survey-wide analysis
from 1966-2007 based on these 280 routes averaged
1.37 individuals per route (Fig. 1.3). BBS trends are
significant and negative only in the Central BBS
Region (-2.5, n = 87, P = 0.00) and USFWS Region
6 (-1.7, n = 114, P = 0.04). Trends are significant
and positive in Oregon (8.2, n = 26, P = 0.05) and
USFWS Region 1 (3.2, n = 79, P = 0.01; Sauer et al.
2008; Fig. 1.4).
In general, species are considered adequately
monitored by the BBS if the standard error (SE)
Figure 1.3. Breeding Bird Survey abundance map (1994–2003; Sauer et al. 2008).
8 Status Assessment and Conservation Action Plan for the Long-billed Curlew (Numenius americanus)
of the estimated rangewide trend is < 0.90 and if
there is no reason to believe that bias (e.g. roadside,
detectability, and survey timing) is especially large
(Bart et al. 2005). Using BBS data, Long-billed
Curlews have a SE of 1.10 (Bart et al. 2005), which
indicates that the BBS may not adequately monitor
Long-billed Curlew trends. An increase in the
number of BBS routes with Long-billed Curlews
could potentially lower the SE below the 0.90
threshold. However, since BBS routes are surveyed
in June, when Long-billed Curlews are largely
inconspicuous (C. L. Gratto-Trevor, pers. comm.),
there seems to be a bias introduced by the timing of
the BBS which an increase in the numbers of routes
would not address. This bias may be substantial and;
therefore, the BBS may not adequately reflect Long-billed
Curlew trends (see Chapter 2, page 15).
Habitat Requirements
Breeding
A literature review by Dechant et al. (2003)
reported that most studies documented Long-billed
Curlews avoiding trees, tall weedy vegetation,
and tall dense shrubs during the breeding season,
and that they nested in the simplest, most open
habitat available. Water availability, minimum
block size, vegetation height, density, structure
and species composition are characteristics whose
importance has been debated. Generalizations
may be meaningless though as foraging, nesting,
and brood rearing habitats used throughout the
breeding season generally require different features
and these differences are not always taken into
consideration when generalizing studies over a
large range. Geographical variability in Long-billed
Curlew habitat reflects both availability and diverse
environmental conditions throughout their range
(e.g. King 1978, Pampush 1980a, Foster-Willfong
2003, Hartman and Oring 2006a).
Water.--The need for open water in proximity to
nesting areas is not clearly defined and creates
diverse opinions (Dechant et al. 2003). The actual
role which standing water plays for Long-billed
Curlews may be based on geographical range, local
environmental conditions, and age of curlews. The
ephemeral nature of water across much of their
range, coupled with their high degree of site fidelity
and long life expectancy (Redmond and Jenni 1982,
1986), may result in annual and seasonal differences
in the amount of water at any particular breeding
site used by curlews (McCallum et al. 1977).
Although not statistically significant, Gratto-
Trevor (2000, 2006) found Long-billed Curlews
used natural wetland basins more frequently than
managed wetlands in southeastern Alberta. Within
these natural wetland habitats, curlews were more
Figure 1.4. Breeding Bird Survey trend map (1966–2003; Sauer et al. 2008).
Chapter 1: Status Assessment 9
commonly found on drier transects which had < 5%
of their length along a wetland (Gratto-Trevor 2000).
Foster-Willfong (2003) found radio-tagged chicks
in Saskatchewan moved toward wetland areas as
they grew and prepared for migration. In Colorado
and Texas, most observations of curlews were found
within 1.6 km of intermittent or standing water
(King 1978).
It has been speculated that wet areas may be more
attractive to foraging curlews due to the loosened
substrate making it easier to probe for food items
as well as attracting more prey items to the area
(Gillihan 1999). In addition, intense livestock grazing
around watering structures may provide the low
vegetation profile preferred by curlews (Gillihan
1999). In Nevada rangelands, agricultural expansion
has created approximately 4000 km2 of irrigated
hayfields and pastures, producing Long-billed
Curlew breeding habitat and resulting in a breeding
range extension (Oring and Hartman 2006).
Habitat block size.--Block size of suitable habitat has
also been considered an important factor for nesting
Long-billed Curlews. Several minimum block sizes
have been recommended for habitat management
planning purposes; however, currently there are few
studies which provide data which could be used to
develop meaningful rangewide minimum block size
recommendations.
In South Dakota in 2005, mean home ranges equaled
1.87 km2 (range 0.70-4.89 km2) and 0.75 km2 (range
0.52-1.00 km2) during breeding and brood rearing
periods respectively (Clarke 2006). In 2006, a
drought year, mean home ranges were 7.71 km2
(range 1.15-29.11 km2) for the entire breeding season
and during the brood rearing period 4.8 km2 (Clarke
2006). Based on these measurements, minimum
block size requirements could be dependent upon
stage of breeding (nesting or brood rearing) and
could show annual differences based on local annual
weather conditions (Clarke 2006).
Vegetation structure during nesting.--Height,
density, and structure of vegetation have also been
investigated as important factors determining Long-billed
Curlew nesting habitat. In Saskatchewan,
pastures of crested wheatgrass (Agropyron
cristatum) were more likely to be used if they had
been grazed prior to the nesting season (Foster-
Willfong 2003). In the Columbia River Basin of
Washington, Allen (1980) found birds nested in
fields of cheatgrass (Bromus tectorum)/Sandberg’s
bluegrass (Poa sandbergii) where the average
heights were < 10 and 20 cm, respectively. Pampush
and Anthony (1993) found annual grass habitats
and open shrubs in Oregon, with a mean effective
height of 16 cm, were preferred over bunchgrass
for nesting. In northeast Oregon, Pampush and
Anthony (1993) found significantly higher nest
density in cheatgrass habitats. These cheatgrass
habitats provided the most open habitat available in
the area (Pampush and Anthony 1993) which may
demonstrate a preference for open habitat and not
a selection of cheatgrass. Within the Teton Valley,
Idaho, Long-billed Curlews nested in heavily to
moderately grazed grasslands but used denser cover
for brood-rearing (Cavallaro 2006). In South Dakota,
on unbroken native mixed-grass prairie rangeland,
nest sites averaged 55% grass cover and 47% forb
cover (Clarke 2006). In addition, Clarke (2006)
found that there was significantly less shrub cover
at nest sites than at random sites. A natural range
fire during the fall, followed by low precipitation, led
to a reduction in vegetative cover during the 2006
nesting season, where curlews selected nest sites
in significantly shorter vegetation than available
(Clarke 2006). Nest sites dominated by a greater
proportion of junegrass (Koeleria macrantha)
and buffalograss (Buchloe dactyloides) had higher
success rates during both years of the study (Clarke
2006). Nesting habitat in Wyoming consists of grass
< 30 cm (Wyoming Game and Fish Department
2005). The sandsage prairies of western Nebraska
rarely exceed one meter in height (King 1978,
Kingery 1998, Sharpe et al. 2001) and host high
densities of breeding Long-billed Curlews (Sharpe
et al. 2001). King (1978) found that the average
height of the tallest vegetation at chick hatch was 11
cm (range 4-23 cm) in Colorado and Texas. Measured
at three meters from the nest site, the average was
20.6 cm (range 7-34 cm).
Vegetation structure during brood rearing.--Foster-
Willfong (2003) noted a shift of use from tame
pastures and native prairies during the nesting
period to spring and summer crop fields which were
used during the brood rearing period. Annual grass
habitat dominated by cheatgrass was preferred for
brood rearing in Oregon as it provided a profusion
of grasshoppers for young to feed on. Fallow ground
and cropland with a low profile, such as potatoes,
wheat, and alfalfa were used as long as crops did
not exceed 30 cm in height. Expansive stands of
bunchgrass were avoided by adults with broods in
Oregon (Pampush 1980a, Pampush and Anthony
1993). In South Dakota, broods used habitats with
a greater proportion of six-week fescue (Vulpia
octoflora), Indianwheat (Plantago patagonica),
junegrass, and American vetch (Vicia americana)
than random points. Creeping spikerush (Eleocharis
palustris) was found in greater proportion in
brood use areas than at random points as well
(Clarke 2006). In Texas and Colorado young birds
concentrated their activity in short and mixed grass
habitats (King 1978).
Winter
Coastal sandy beaches, intertidal mudflats, salt
marshes, coastal and inland pastures and farmlands,
freshwater wetlands, salt ponds, and agricultural
pastures are used by wintering Long-billed
Curlews (Page and Gill 1994, Colwell and Sundeen
2000, Colwell and Mathis 2001, Colwell 2006).
Variations across the nonbreeding season from fall
through spring, as well as daily variations make
generalizations about winter habitat difficult. Tides
also affect the availability of foraging and loafing
areas at coastal areas (Colwell and Mathis 2001).
10 Status Assessment and Conservation Action Plan for the Long-billed Curlew (Numenius americanus)
During the late fall, curlews were foraging on
mudflats of Humboldt Bay region of northern
California at intermediate and low tides, in the
surrounding agricultural fields at intermediate
and high tides when mudflats were not available,
and were not observed using salt marshes in
significant numbers (Long and Ralph 2001).
Pasture use increased by mid-winter in the region
to the point that most curlews were feeding there
even at low tide (Colwell and Mathis 2001). They
hypothesized that availability of earthworms in
pastures, coinciding with the seasonal onset of
rains, is an important condition in determining the
number of nonbreeding curlews in the Humboldt
Bay region (Colwell and Mathis 2001). Curlews
were found to use intertidal territories or pastures
only during daylight hours and used the bay at
night (Leeman and Colwell 2005). Some curlews
may use agricultural pastures for winter foraging
habitat independent of tide (Leeman and Colwell
2005). Proportionately more Long-billed Curlews
were observed roosting, rather than foraging, on
pastures during high tide. This may reflect a need
for inland high tide roosts rather than an immediate
need for feeding areas (Leeman and Colwell 2005).
Winter use was greater on estuary sites which
ebbed earlier and tended to be more channelized.
Long-billed Curlews flew directly from their high-tide
roosts to the tidal flats and then dispersed to
feeding territories as the sites became exposed
by the outgoing tide (Danufsky and Colwell 2003).
Farther south along the coast, Stenzel et al. (1976)
observed curlews feeding on the tidal flats during
low tide or occasionally feeding in the salt marsh but
not along the coast or in neighboring pasturelands
in their study of wintering birds at Bolinas Lagoon,
California.
In winter, curlews in Arizona and New México
were found using plowed, harvested, and grassy
agricultural fields, flooded fields, desert grasslands
and cut-over alfalfa fields (Monson and Phillips
1981; Corman and Wise-Gervais 2005; W. H. Howe,
pers. comm.). In Nevada, wintering birds have been
observed using emergent marshes and flooded
saltgrass (Distichlis spicata) or mudflats (L. A.
Neel, pers. comm.). During the nonbreeding season
inland birds in southern Texas used grasslands
and brushlands (Igl and Ballard 1999). Long-billed
Curlews wintering in Jalisco, México roost in high-elevation
mangroves at Barra de Navidad lagoon
and in sandbars and dunes at high tide in Agua
Dulce lagoon (S. Hernández-Vázquez and F. G.
Cupul-Magaña, pers. comm.).
Migration
Little information is available on specific habitat
characteristics used by Long-billed Curlews during
migration. Individual birds may remain year round
at some sites so it is often impossible to distinguish
migration habitat from wintering and over-summering
habitat.
Staging areas include coastal and inland sites in
both managed and natural habitats (Paulson 1993,
Davis and Smith 1998, Rivers and Cable 2003, Shane
2005). Long-billed Curlews migrating through
the interior of North America use fallow, plowed,
wheat, and alfalfa fields, sparsely vegetated areas
such as prairie dog colonies, low grassland fields,
shallow wetlands, and lake and reservoir edges
for foraging and roosting (Paulson 1993; Shane
2005; D. S. Stolley, pers. comm.; E. A. Young, pers.
comm.). Many agricultural sites used by curlews
have center pivot irrigation systems (Shane 2005).
In the southern Great Plains, curlews use farmed
playas (Rivers and Cable 2003) and saline lakes to
a lesser extent (Davis and Smith 1998, Andrei et
al. 2006). Long-billed Curlews were observed in
greater numbers on agricultural fields in California’s
Imperial Valley than on the shorelines and river
deltas of the Salton Sea (Shuford et al. 2002a). In
Indiana, migrating Long-billed Curlews occurred
on isolated wet prairie habitats (B. McCoy, pers.
comm.).
Pacific Coast migrants are found along beaches,
mudflats, deltas and other wetlands (Campbell 1972,
Paulson 1993). Along the southern Atlantic and
eastern Gulf coasts, migrating Long-billed Curlews
are found on beaches and mudflats associated with
creek inlets and barrier islands (S. L. Melvin and B.
Winn, pers. comm.) as well as on manicured lawns
(B. A. Andres, pers. comm.).
Threats
Initial population declines were attributed to
over-hunting and plowing of the native prairies
for agriculture (Oring 2006, Oring and Hartman
2006, Russell 2006). Current rangewide threats
include habitat loss and destruction due to urban
development, grassland conversion for agricultural
purposes, changes in the natural fire regime, and
the spread of exotic invasive plants (Pampush 1980a,
Pampush and Anthony 1993, Oring 2006, Askins
et al. 2007). At the local level, predation, grazing
practices, energy development, diseases, and
pesticides and contaminants are potential threats
(Clarke and Jensen 2006, Johnson 2006, Oring 2006).
Destruction of nests and human disturbance have
also been considered a threat (King 1978).
Over-utilization
Long-billed Curlews were heavily exploited during
the commercial market shooting period in the U.S.
(Oring 2006, Russell 2006). Curlews were easily
brought into shooting range using decoys and they
responded to distress calls by flocking towards
wounded birds which resulted in large numbers
being harvested in a single shooting event (Blanchan
1904). Although currently protected by the
Migratory Bird Conventions between the U.S. and
Canada and México (U.S. Fish and Wildlife Service
2008a) illegal shooting may still occur, although
probably at low levels (Cannings 1999).
Chapter 1: Status Assessmen t 11
Habitat Loss
Destruction of prairie grassland habitat and
increased agricultural use has altered the historical
breeding distribution of Long-billed Curlews (King
1978, Hartman and Oring 2006b, Oring 2006).
Extensive loss of habitat has been documented
throughout their historical range (Dahl 1990,
Pampush and Anthony 1993, Knick et al. 2003).
Urban development (Oring 2006), plowing of
grasslands for crops (Pampush 1980a, Russell
2006), a shift in agricultural use from grazing to
farming (King 1978, Pampush and Anthony 1993),
the subsequent loss of native prairies in the midwest
region of the U.S. (Russell 2006), and changes in the
natural fire regime (Pampush 1980a) have all led to
habitat loss and fragmentation across the breeding
range of Long-billed Curlews.
Introduced invasive plant species have altered the
physical and community structure of many western
grass and shrubsteppe habitats (Pimentel et al.
2005). Extirpation of Long-billed Curlews from
their historical eastern range may be attributed
to the spread of exotic species following the loss
of American bison (Bison bison) and the plowing
of native prairie in the midwest region of the U.S.
(Russell 2006). Exotic invasive species such as
diffuse knapweed (Centaurea diffusa) are thought to
be avoided by breeding curlews (Committee on the
Status of Endangered Wildlife 2002).
Cheatgrass is an invasive grass now found
throughout the breeding range of Long-billed
Curlews. Although Long-billed Curlews are known
to nest in cheatgrass-dominated habitats in high
densities (Pampush 1980a), Allen (1980) found them
only using mixed cheatgrass/Sandberg’s bluegrass
when the cheatgrass component was < 10 cm tall.
This is an issue in the Columbia Basin region of
eastern Oregon and Washington, where National
Wildlife Refuges (NWR) are replanting native
vegetation in areas where Long-billed Curlews
breed in relatively high densities (S. M. Thomas,
pers. comm.). Land managers in Utah have also
noted a high density of nesting curlews in cheatgrass
(K. A. Hersey, pers. comm.).
Historically, regular fires and grazing maintained the
grasslands used by breeding Long-billed Curlews
in a relatively treeless condition (Askins 2007).
Large blocks of planted trees (such as shelterbelts
or windbreaks) are often planted to protect tilled
areas from the effects of wind and lessen soil erosion
(Dronen 1984). This addition of trees to grasslands is
a threat to suitable breeding habitat for Long-billed
Curlews (Dechant et al. 2003).
Invasive species also pose a potential threat to
Long-billed Curlew habitat along migratory routes
and in wintering areas. Cordgrass (Spartina
alterniflora), is an introduced invasive species found
in the tidal marsh plains, channels, and mudflats of
the San Francisco Bay estuary of California. This
threat could reduce Long-billed Curlew use of the
bay substantially during both the spring and fall
migration (Stralberg et al. 2004).
Predation
Mammalian and avian predators have been
linked to decreased local breeding success of
Long-billed Curlews. Coyotes (Canis latrans;
Oring 2006, Oring and Hartman 2006), red foxes
(Vulpes vulpes; Paton and Dalton 1994, Gorrell
et al. 2005), badgers (Taxidea taxus), long-tailed
weasels (Mustela frenata; Redmond and Jenni
1986), Prairie Falcons (Falco mexicanus; Oring
and Hartman 2006), Northern Harriers (Circus
cyaneus), Short-eared Owls (Asio flammeus; Clarke
and Jensen 2006), gopher or bullsnakes (Pituophis
catenifer; Kingery 1998), and corvids such as crows
(Corvus spp.), magpies (Pica spp.; Pampush 1980a,
Redmond and Jenni 1986, B. Olson, pers. comm.),
and Chihuahuan Ravens (Corvus cryptoleucus;
King 1978) have been documented as predators of
Long-billed Curlew chicks and eggs. Researchers
inadvertently attracting predators to nest sites have
also been noted (Allen 1980). However, intensities
and sources of predation are extremely variable and
often contradictory throughout the breeding range
(Pampush 1980a, Paton and Dalton 1994, Oring 2006)
and more information on their impact is needed
(Paton and Dalton 1994, Oring 2006).
Grazing
In Colorado and Texas, the overall direct effects of
cattle (Bos taurus) grazing were found to be minimal
(King 1978). In South Dakota, 75% of Long-billed
Curlew nest loss was attributed to trampling by
bison (Clarke and Jensen 2006). Domestic sheep
(Ovis aries) in Idaho were responsible for some
nest loss (Redmond and Jenni 1986). Deterioration
of native grasslands by extensive cattle and sheep
grazing has also led to the fragmentation of prairie
grasslands and introduction of invasive species such
as cheatgrass in some locations (Pampush 1980a).
Energy Development
Energy development, such as oil and gas and mining
activities occurs throughout Long-billed Curlew
breeding range (Knick et al. 2003). Oil and gas
shipping along the Pacific and Gulf coasts poses a
potential threat from oil spills which could destroy Long-billed Curlew chick. Cory Gregory©.
12 Status Assessment and Conservation Action Plan for the Long-billed Curlew (Numenius americanus)
habitat and food resources for nonbreeding Long-billed
Curlews (U.S. Coast Guard 2003). The recent
increase in demand for renewable energy resources
may present an additional threat since much of
the area targeted for wind power development is
within the central prairies and western grassland
and shrublands that comprise the primary breeding
range of Long-billed Curlews (U.S. Department of
Energy 2008). Threats to Long-billed Curlews from
wind energy may be due to either or both the loss
and fragmentation of breeding habitat or due to
direct hits on the wind towers. The intensity of the
threat could be related to wind farm location and
times of operation (Stewart et al. 2007).
Long-billed Curlews may be vulnerable to direct
mortality due to strikes from rotor blades (W. H.
Howe, pers. comm.), increased predation associated
with the added structures and incursion into
grasslands, disruption of aerial breeding displays,
disturbance caused by increased human activity
during both the development stage and during
general maintenance of the wind farm, and habitat
fragmentation (Erickson 2006, Johnson and Shaffer
2006, Robel 2006, Strickland 2006). It is unknown if
Long-billed Curlews exhibit avoidance to the towers
and would thus be affected by the mere presence of
a windmill. Winkelman (1992 in Stewart et al. 2007)
showed a significant decrease in local populations
in coastal Holland of the European Curlew
(Numenius arquata), a species with similar habitat
requirements.
Biofuels, such as corn-derived ethanol, have lead
to the increased conversion of native prairie and
rangelands to corn production (Stubbs 2007,
Scharlemann and Laurance 2008). Several of the
primary areas in North America for corn production
coincide with the breeding range of Long-billed
Curlews. Ethanol production has the potential to
directly reduce wildlife habitat (DeLuca 2007, Secchi
and Babcock 2007, Stubbs 2007) and could increase
threats to Long-billed Curlew breeding populations
in these areas.
Disease
Aspergillosis, a respiratory tract infection caused
by fungi, was responsible for the deaths of chicks in
Idaho (Redmond and Jenni 1986). Other diseases
have not been reported.
Pesticides
Blus et al. (1985) collected eggs in 1978 in Oregon to
test for organocholorine-induced mortality in Long-billed
Curlews. Although eggs were determined
to have DDE residues and low levels of heptachlor
epoxide, oxychlordane, and PCB residues, there was
no significant egg shell thinning (Blus et al. 1985). In
the early 1980s, oxychlordane, heptachlor epoxide,
and dieldrin levels in the brains were within levels
associated with mortality in experimental birds (n =
3; Blus et al. 1985). DDE, DDT, PCBs, and several
other chlorinated hydrocarbon pollutants were also
detected (Blus et al. 1985).
Recently, a 20% failure of egg hatch in Nevada
has led to a contaminant analysis of eggshell
thickness and comparison with pre-DDT (prior to
1944) specimens (Oring 2006). Significant eggshell
thinning was determined to have occurred. As most
uses of pesticides containing organochlorides have
been banned in the U.S., it is suggested that Long-billed
Curlews are being exposed to organochloride
pesticides on their wintering grounds (Oring 2006,
Blus et al. 1985).
Spraying for grasshoppers (suborder Caelifera,
order Orthoptera) and Mormon crickets (Anabrus
simplex) is conducted throughout much of the
Long-billed Curlew breeding range when cricket
numbers reach high levels (Animal and Plant Health
Inspection Service 2003). Currently carbaryl,
diflubenzuron, and malathion are the most commonly
used pesticides for control in the U.S. (Animal and
Plant Health Inspection Service 2003). It is unknown
if these pesticides or this spraying constitute a
threat to Long-billed Curlews.
Other
Vehicles.--Vehicle traffic, for recreational,
commercial, and scientific purposes, was documented
in the direct loss of Long-billed Curlew nests and
eggs (King 1978). Farming practices such as field
fertilization, dragging for cow manure in grazed
pastures (Committee on the Status of Endangered
Wildlife 2002), and plowing wheat stubble also led to
nest destruction (King 1978).
Disturbance.--King (1978) noted that in areas
where there were low levels of disturbance, such as
overhead planes or vehicular traffic along roadways,
incubating Long-billed Curlews maintained a
crouched posture and did not respond as if unduly
threatened. However, low level (150 m) military
aircraft flying training maneuvers did elicit alarm
responses in birds in Texas (King 1978), while
regular intense activity at a military bombing range
in Oregon did not elicit an alarm response (Pampush
1980a). Nesting curlews seemed to have become
acclimated to the disturbance and did not treat it as
a threat (Pampush 1980a).
Chapter 1: Status Assessmen t 13
Recommendations
Although the population is higher then previously
thought, Long-billed Curlew populations are lower
than historically and their range continues to
contract. We believe that high levels of concern for
Long-billed Curlews are warranted, particularly
in the shortgrass and mixed-grass prairies of the
western Great Plains. The only existing long-term
monitoring program, the BBS, shows negative
population trends throughout much of the breeding
range, although in many areas these trends are non-significant
(Sauer et al. 2008). Documented declines
have occurred in several parts of the continent,
including the reduction of breeding range and fewer
migrants observed along the Atlantic coast.
The effects of energy development, including wind
power and bio-fuel development, in the Great
Plains and throughout the west, may become
significant forces in changing current habitat and
resulting in the displacement of Long-billed Curlew
breeding populations. Current population level
threats, including habitat loss and fragmentation,
encroachment of woody vegetation, urban
development, the spread of exotic invasive plants,
and threats due to contaminants such as pesticides,
continue to affect the species on both the breeding
and wintering grounds.
In Chapter 2, we present a Conservation Action
Plan for Long-billed Curlews. We believe that the
conservation of this unique and amazing species
should continue to be a high priority throughout the
continent. We hope that this document will direct
and contribute to their long term conservation.
In Chapter 3, we present more detailed summaries
on the status of curlews in states and provinces
throughout their range.
14 Status Assessment and Conservation Action Plan for the Long-billed Curlew (Numenius americanus)
Introduction
The Conservation Action Plan (Plan) for Long-billed
Curlews was developed and prioritized by a diverse
group of partners interested in Long-billed Curlew
conservation. This Plan includes a prioritized list
of actions and needs that we believe will assist us
to achieve long-term rangewide conservation of
Long-billed Curlews (Table 2.1). Implementing
effective conservation measures will require
the cooperation of a coalition of local, regional,
national, and international partners (Harrington
et al. 2002). Since micro-habitat use by Long-billed
Curlews varies within and across seasons and
geographic areas, management will require local
and seasonal components (Colwell and Sundeen
2000, Foster-Willfong 2003). In addition to this
Plan, several states have developed objectives and
actions designed to address state-wide conservation
of Long-billed Curlews as part of their State
Wildlife Grant programs (Hagen et al. 2005, Idaho
Department of Fish and Game 2005, New Mexico
Department of Game and Fish 2006).
The goal of this Plan is to identify appropriate
management techniques to halt and, hopefully,
reverse population declines in this species. To
achieve this goal, several important steps have
been taken towards identifying limiting factors and
creating a prioritized rangewide Plan. The first
step identified to achieve this goal was to estimate
the rangewide breeding population size of Long-billed
Curlews and determine how populations were
distributed within their breeding range (Jones et
al. 2008). A survey in Alberta of breeding Long-billed
Curlews (Saunders 2001) and the subsequent
rangewide survey in 2004-2005 were the first
broad-scale attempts towards achieving a defensible
population estimates for Long-billed Curlews
(Stanley and Skagen 2007, Jones et al. 2008). In
addition, current and historical breeding-range
studies have begun to identify local habitats used by
Long-billed Curlews (Hartman and Oring 2006a, b;
Redmond and Jenni 1982), and these characteristics
can be used in landscape planning efforts. The
Long-billed Curlew Symposium at the 2006 Western
Hemisphere Shorebird Science Meeting in Boulder,
Colorado, helped to facilitate discussion among
Long-billed Curlew scientists and land managers
(Oring 2006). Subsequent discussions have led to
identification and prioritization of the needs outlined
in this Plan.
Results from the rangewide breeding survey
indicated that the overall population of breeding
Long-billed Curlews is greater than previously
thought (Table 1.2; Morrison et al. 2001, 2006;
Jones et al. 2008). These results also indicated that
breeding birds are generally evenly distributed
throughout their present range (Jones et al.
2008). Because of this distribution, there are no
broad-scale threats that have been identified that
are negatively affecting the entire population and
require immediate action or study. However, current
indications are that landscape changes, which led
to the approximately one-third contraction in their
historical breeding range, may still be limiting
population growth of Long-billed Curlews in parts of
their range.
Therefore, we recommend that conservation actions
be prioritized as follows:
(1) Evaluate monitoring methods, specifically those
issues related to the BBS. We must ascertain if
the trends produced from the BBS are reliable,
particularly with regards to timing of the survey
and precision (or bias). We need to know the cur-rent
status of the species, and the direction and
magnitude of any trend.
(2) Identify the types and intensity of current
threats, on breeding, migration, and wintering
grounds. It is important to identify exactly where
and what level of risk perceived threats pose to
Long-billed Curlew populations.
(3) Identify critical migration staging areas and de-termine
if threats there (e.g. development, altera-tions
to hydrology, contaminants, and disease)
are limiting Long-billed Curlews’ ability to gain
weight and successfully complete migration. Re-duction
in stopover quality might also negatively
affect survival and subsequent reproduction.
(4) Identify critical winter areas and specifically de-termine
how Long-billed Curlews are distributed
throughout their wintering range.
(5) Determine the causes of the breeding range con-tractions
and identify those factors that continue
to limit population growth throughout the breed-ing
range.
(6) Determine if Long-billed Curlews are positively
responding to management actions designed for
their conservation.
(7) Assess if environmental factors on the wintering
grounds could be limiting Long-billed Curlew
population growth.
Chapter 2: Conservation Action Plan
Chapter 2: Conservation Action Plan 15
Priority Actions
Population Monitoring and Assessment
BBS data suggest a population decline, although the
results are not statistically significant (1966-2007),
except in USFWS Region 6 and the Central BBS
Region (Sauer et al. 2008), where range contraction
is still occurring. Precision of trend estimates is
poor, which is probably related to the low numbers
of Long-billed Curlews detected on each route
(rangewide = 1.37 individuals/route; Sauer et al.
2008). The priorities are to evaluate the adequacy of
the BBS to monitor breeding populations.
1.0. Inherent BBS assumptions should
be tested to see if they are valid for Long-billed
Curlews.
1.1. Detectability. A basic BBS assumption
is that there is no relationship between detectability
and density (i.e. a constant proportion is always
detected, and the proportion detected is a function
of the number of birds present). This can be
examined using the rangewide survey dataset, since
detectability was estimated using double-observer
and time-removal methods.
1.2. Road Bias. A preliminary analysis
(Stanley and Skagen 2007) determined that Long-billed
Curlew numbers did not vary as a function of
distance from road. Another issue with roads would
be to determine if trends along roads mirror the
broader landscape for suitable Long-billed Curlew
habitat. This could be examined by assessing habitat
similarity near and away from roads using GIS.
There may be regional differences in this effect.
Densities of Long-billed Curlews on roads versus
off-roads would likely be different, but that would
not be an issue if the trends are the same and a
constant proportion is detected (the detectability
assumption specified above is being satisfied).
2.0. Currently, the BBS cannot be used
to monitor Long-billed Curlews due to the low
precision. This can be addressed two ways.
2.1. Increase the number of routes. This
could be achieved by augmenting the number of
BBS routes surveyed, along the lines of the current
project in Canada that is conducting additional
grassland routes (B. Dale, pers. comm.). We would
statistically evaluate this by increasing the number
of routes and investigating the periodicity (e.g. every
5 years), which they would be run.
2.2. Time-of-year. Perhaps the biggest
concern regarding Long-billed Curlew monitoring
is the timing of BBS surveys, which typically occur
in June. This time period corresponds with the
latter stages of breeding when Long-billed Curlews
are most inconspicuous (late incubation period
or, in some areas, after the young have already
fledged and birds have departed the breeding
area). This may create two potential problems: a)
clumped distributions in June could lead to greater
variance (lower precision) in estimates and b) lower
detectability of curlews on routes, since Long-billed
Curlews are more likely to be less visible and
not as vocal. These problems could be examined
by comparing data collected on the range-wide
survey and the BBS. This assumes that inherent
BBS assumptions are still being satisfied and that
increased sample size does not mitigate these
problems.
Long-billed Curlew’s wing, July 3, 2008. Cory Gregory©.
16 Status Assessment and Conservation Action Plan for the Long-billed Curlew (Numenius americanus)
Currently, a survey is being conducted in north
and east North Dakota to use the BBS routes
to survey grassland and marshland breeding
shorebirds (N. Niemuth, pers. comm.). This survey
will be expanded in 2009-2010, and will survey
approximately 15-45 routes in portions of South
Dakota, North Dakota, and eastern Montana
between 1–15 May. This project will use BBS
techniques to improve our understanding of the
population status of breeding shorebirds, including
Long-billed Curlews, Willets (Tringa semipalmata),
Marbled Godwits, Wilson’s Phalaropes (Phalaropus
tricolor), Wilson’s Snipe (Gallinago delicata), and
Upland Sandpipers (Bartramia longicauda; SLJ
and N. Niemuth, pers. comm.).
Migration Staging and Wintering Areas
Although work has been completed on estimating
population size and determining breeding
distribution, we have still not identified all of the
important sites used by wintering and staging Long-billed
Curlews, particularly in México. As a general
strategy, we believe we should initially emphasize
identifying critical migration and wintering areas,
assessing their functional ability to support Long-billed
Curlews, and then, if warranted, develop
conservation actions and evaluation measures for
these areas (Table 2.1).
Habitat Assessment and Management
While many threats have been identified, there has
been little work on Long-billed Curlew responses
to suggested and implemented conservation and
management interventions. For example, there is
some evidence that human activity can alter use of
ocean beaches by shorebirds (Pfister et al. 1992).
However, whether or not Long-billed Curlews are
similarly affected by this type of disturbance has
not been determined. Concomitantly, it is unknown
if Long-billed Curlews would positively respond to
beach closures if this action was taken. The effects
of energy development on Long-billed Curlews are
not fully understood. Pre-project investigations
should be made a priority in areas suggested for
wind power or oil and gas development (Texas Parks
and Wildlife Department 2005). Consequences of
increased biofuel production on Long-billed Curlews
are unknown but could likely decrease breeding
habitat in the eastern portion of their range.
Knowledge of the response of breeding Long-billed
Curlews to invasive species, such as cheatgrass, and
the effects of both timing and method of eradication
actions are needed to make informed management
recommendations. Grazing, haying, and prescribed
burning are all recommended management tools
for maintaining native prairie grasslands for
breeding Long-billed Curlews (Hagen et al. 2005).
Determining the best timing and intensity of these
management tools are important to maximize
benefits and reduce disturbance (Hagen et al.
2005). However, recommendations can vary across
the curlew’s range, and management of other
high priority wildlife species (e.g. prairie-dogs)
could conflict with recommendations developed
for Long-billed Curlews (Clarke and Jansen 2006;
Foster-Willfong 2003; Montana Fish, Wildlife and
Parks 2005). This spatial variation and possible
management conflicts reinforce the need for local
evaluation of management actions that can then be
integrated into a rangewide perspective (Table 2.1).
Research
Research needs were identified and prioritized by
the Long-billed Curlew Working Group. Research
needs are focused on information gaps that could
be helpful in identifying limiting factors and the
risk posed by perceived threats. Also, priority
research needs were identified to focus on data that
is required for population modeling exercises (Table
2.1).
Long-billed Curlew, Galveston Island, Texas. Bob Gress©.
Chapter 2: Conservation Action Plan 17
Table 2.1. Recommended prioritized conservation actions for Long-billed Curlews (LBCU) throughout their range. This list serves to identify conservation action items
that could lead to the conservation of this species. Where “Lead Party” has been identified it is not meant to obligate any party to provide funding or implement the
action. In a few cases, potential partners and costs have been identified; in most cases that needs to be completed.
Task Action Annual Action Lead Potential Cost (K) Cost (K) Duration Comments
Group Cycle Item Party Partners per year Total
1.0 Population Monitoring and Assessment Breeding Test inherent assumptions of the BBS. FWS
	
	
	
1.1 Population Monitoring and Assessment Breeding Detectability as a function of density, i.e., is the FWS USGS,
		 proportion detected a function of the number of 	 state agencies,
		 birds present. 	 NGOs 10 10 1yr
1.2 Population Monitoring and Assessment Breeding Road bias. Do trends along roads mirror the
		 landscape in general for LBCU? FWS USGS,
				 state agencies,
				 NGOs 10 20 2yr
2.0 Population Monitoring and Assessment Breeding Test/develop methods to improve the poor precision FWS State agencies,
	 	 of the BBS. This project will include 2.1 and 2.2, 	 NGOs 21 42 2yr N. Niemuth, and S.
	
		 below. The area of this project is ND, SD, e. MT. 					 Jones, in 2009-2010
	
	
	
	
	
	
	
	
	
2.1 Population Monitoring and Assessment Breeding Increase the number of routes and evaluate the effect. FWS Above 			 Above
2.2 Population Monitoring and Assessment Breeding Time-of-year. Examine by comparing data collected FWS Above 			 Above
		 in rangewide survey vs. BBS data. BBS routes will
		 be run during 1-15 May.
3.0 Population Monitoring and Assessment Migration Identify and map migratory pathways and important FWS,
		 stop-over sites between breeding grounds and the state agencies
		 wintering grounds.
	
	
	
	
	
	
	
	
4.0 Population Monitoring and Assessment Migration Determine movements of birds to and from breeding
		 sites; timing, locations of critical migratory stop-over,
		 and length of stay.
	
	
	
	
	
5.0 Population Monitoring and Assessment Migration Determine micro-habitat requirements for migration
		 sites.
	
	
	
	
	
6.0 Population Monitoring and Assessment Wintering Complete a map of current Long-billed Curlew FWS,
		 wintering range and habitat. state agencies,
			 México
	
	
	
7.0 Population Monitoring and Assessment Wintering Assess the importance of wintering sites through
		 LBCU range.
	
	
	
	
	
8.0 Population Monitoring and Assessment Wintering Determine important areas that support winter roosts.
	
	
	
	
9.0 Population Monitoring and Assessment Wintering Determine distribution, abundance, and habitat use of
		 LBCU wintering at inland and coastal sites.
18 Status Assessment and Conservation Action Plan for the Long-billed Curlew (Numenius americanus)
Table 2.1. continued
Task Action Annual Action Lead Potential Cost (K) Cost (K) Duration Comments
Group Cycle Item Party Partners per year Total
10.0 Population Monitoring and Assessment Wintering Assess existing levels of conservation protection for
		 wintering habitats.
	
	
	
	
	
11.0 Population Monitoring and Assessment Wintering Conduct research on Long-billed Curlew wintering
		 ecology.
	
	
	
	
	
12.0 Population Monitoring and Assessment Wintering Determine importance of water, and required distance
		 from wintering areas.
	
	
	
	
	
13.0 Population Monitoring and Assessment Wintering Determine threats and limiting factors on the federal agencies WHSRN, JVs,
		 wintering grounds. 	 state agencies
	
	
	
14.0 Population Monitoring and Assessment Wintering Quantifying the effects of disturbance on coastal Universities, FWS
		 wintering grounds e.g. human recreational activity, NGOs
		 particularly on foraging rates and habitats.
	
	
	
	
	
1.0 Habitat Assessment and Management Breeding Determine micro- and macro- habitats across the FWS Texas A & M 10 10 1 year Completed, Saalfeld
		 breeding range, using data from rangewide survey. 					 et al. 2008.
2.0 Habitat Assessment and Management Breeding Improve LBCU breeding habitat in North America, Shorebird FWS, USGS,
		 including publishing recommendations as Best Temperate Grp; NGOs
	
	
		 Management Practices. JVs
	
	
	
2.1 Habitat Assessment and Management Breeding Improve LBCU breeding habitat and Best JVs FWS, USGS, 10 10 1 year
		 Management Practices - Northern Prairies. 	 NGOs
	
2.2 Habitat Assessment and Management Breeding Improve LBCU breeding habitat and Best JVs FWS, USGS, 10 10 1 year
		 Management Practices - Great Basin and 	 NGOs
		 sagebrush grasslands.
	
	
2.3 Habitat Assessment and Management Breeding Improve LBCU breeding habitat and JVs FWS, USGS, 10 10 1 year
		 Best Management Practices - shortgrass prairies. 	 NGOs
3.0 Habitat Assessment and Management Breeding Determine minimum habitat requirements.
	
	
	
	
4.0 Habitat Assessment and Management Breeding Determine effects of energy development, particularly
		 oil and gas and wind farms; determine appropriate
		 mitigation recommendations.
	
	
	
	
	
4.1 Habitat Assessment and Management Breeding Assess effects of wind power and oil/gas development -
		 habitat fragmentation.
	
	
	
	
	
4.2 Habitat Assessment and Management Breeding Assess effects of wind power and oil/gas development -
		 infrastructure.
	
	
	
	
	
4.3 Habitat Assessment and Management Breeding Assess effects of wind power and oil/gas development -
		 nesting success.
Chapter 2: Conservation Action Plan 19
Table 2.1. continued
	
	
	
	
	
Task Action Annual Action Lead Potential Cost (K) Cost (K) Duration Comments
Group Cycle Item Party Partners per year Total
4.4 Habitat Assessment and Management Breeding Assess effects of wind power and oil/gas development -
		 interference with breeding/territorial display/defense.
	
	
	
	
4.5 Habitat Assessment and Management Breeding Assess effects of wind power and oil/gas development -
		 strike hazard.
	
	
	
	
5.0 Habitat Assessment and Management Breeding Assess effects of invasive species (e.g. cheatgrass)
		 on LBCU nesting success, across the geographic
		 and habitat range of the species.
	
	
	
	
	
6.0 Habitat Assessment and Management Breeding Determine the best timeline for habitat restoration,
		 seed mixtures, and the response to restoration,
		 across its range.
	
	
	
	
	
7.0 Habitat Assessment and Management Breeding Determine if collisions are a threat and methods
		 to reduce/mitigate risks from collisions (e.g. wind
		 farms, communications towers).
	
	
	
	
	
8.0 Habitat Assessment and Management Migration Protect, restore, and protect migration and staging
		 habitat. 	 WHRSN, JVs,
				 state agencies
	
	
	
9.0 Habitat Assessment and Management Wintering Protect and improve LBCU habitat in wintering
		 grounds.
	
	
	
	
	
	
1.0 Research Breeding Reduce critical knowledge gaps regarding Researchers, Universities,
		 demographics, population size and trend, adult USGS NGOs,
		 survival, and life history. 	 state agencies
	
	
	
	
	
1.1 Research Breeding Estimate reproductive success and breeding habitat FWS State agencies,
		 use in geographic areas where information is lacking. 	 NGOs
	
	
	
1.2 Research Breeding Determine adult and juvenile survival rates across
		 breeding range and in a variety of micro-habitats.
	
	
	
	
	
1.3 Research Breeding Increase knowledge about dispersal patterns
		 (juvenile and adult) and factors affecting dispersal.
	
	
	
	
	
2.0 Research Breeding Assess potential effects of various non-habitat limiting
		 factors.
	
	
	
	
	
2.1 Research Breeding Assess role of water in different areas, and at different
		 stages in the reproductive cycle.
				20 Status Assessment and Conservation Action Plan for the Long-billed Curlew (Numenius americanus)
Table 2.1. continued
	
	
	
	
	
Task Action Annual Action Lead Potential Cost (K) Cost (K) Duration Comments
Group Cycle Item Party Partners per year Total
2.2 Research Breeding Evaluate the effect of predation across a wide
		 geographic range.
2.3 Research Breeding Evaluate the effect of cattle/bison grazing at different
		 stocking rates and rotation timing.
	
	
	
	
	
2.4 Research Breeding Evaluate the effects and timing of other disturbances
		 (e.g. haying, fire).
	
	
	
	
	
3.0 Research Breeding Compile information on reproductive success from
		 across the breeding range, for an evaluation for a
		 population viability analysis.
	
	
	
	
	
4.0 Research Breeding Assess how important and extent of colonial and
		 semi-colonial nesting.
	
	
	
	
	
5.0 Research All Assess importance of contaminants such as pesticides,
		 heavy metals.
	
	
	
	
	
6.0 Research Breeding Investigate correlations between climate changes,
		 timing of spring arrival of LBCU on breeding grounds.
	
	
	
	
1.0 Education and Outreach Breeding LBCU projects for education and outreach on the value
		 of conserving intact native shortgrass and mixed-grass
		 prairie.
					Chapter 2: Conservation Action Plan 21
Education and Outreach
Development of education and outreach tools
were recurring themes in every category of the
recommended conservation actions. Long-billed
Curlew conservation will require public and
landowner education and outreach on the value of
conserving intact native shortgrass prairie. Long-billed
Curlews are large, conspicuous birds and
are a good flagship species of prairie grassland
ecosystems. As such, they can be effectively used to
introduce prairie conservation into classrooms and
communities (Table 2.1).
Other Species Covered
Many grassland management actions, such as
increasing dense nesting cover to increase waterfowl
nesting, have the potential to negatively affect
habitat use by breeding Long-billed Curlews
(Prairie Habitat Joint Venture 2000). While a
number of grassland breeding shorebirds overlap
with Long-billed Curlews in range and general
habitat use, this species may not be a good indicator
or umbrella species for habitat management.
However, many of these species will be covered in
the monitoring survey discussed above. Marbled
Godwits, Willets, and Upland Sandpipers generally
use similar habitats in portions of the Long-billed
Curlew’s range, but significant portions of their
ranges do not overlap with curlews. In addition,
micro-habitat needs (i.e. gradients of grass density
and wetness) for Willets and Upland Sandpipers
do not overlap well with Long-billed Curlews.
Mountain Plover (Charadrius montanus) habitat
requirements are generally quite different from
those of Long-billed Curlews, although their ranges
do overlap. In areas where Long-billed Curlews are
a component of the breeding bird community, habitat
managers should try to integrate adequate curlew
habitat requirement needs into their management
plans.
Priority Populations and Regions
Long-billed Curlews can be divided into ecological
groups, based on vegetation regimes, ecoregions,
and political boundaries (Table 1.2). Within each
physiographic region, Long-billed Curlews appear
to have some different micro-habitat requirements
which need to be taken into consideration when
implementing management actions. Population
numbers have been estimated for these divisions
(Table 1.2).
Conservation Strategy
This Plan is a product of a diverse group of agencies,
organizations, and individuals with an interest in
Long-billed Curlew conservation. The conservation
strategy outlined here will address threats to both
breeding and non-breeding habitat and assess
potential threats from non-habitat factors. During
2001 and 2002, the Temperate Breeding Group
(Bart et al. 2005) of the shorebird monitoring group,
Program for Regional and International Shorebird
Monitoring (PRISM), initiated work on a number of
the conservation actions for Long-billed Curlews. In
February 2006, a workshop was held on Long-billed
Curlew research and conservation and management
needs, which provided the basis for the conservation
needs identified here. The conservation strategy
for this species includes maintaining an active
Long-billed Curlew working group, developing
a broad-based partnership to deliver Long-billed
Curlew and temperate breeding shorebird
conservation, increasing available funding for
Long-billed Curlew research, and increasing partner
attention to the habitat needs of the species.
Completed and On-going Conservation Actions
Since its inception in 2001, the Temperate Breeding
Group (Bart et al. 2005) of PRISM has initiated, and
completed, work on a number of the conservation
actions identified for Long-billed Curlews.
(1) Completed the rangewide survey (Stanley and
Skagen 2007, Jones et al. 2008).
(2) Analyzed the population size estimates, including
those in Canada (Jones et al. 2008).
(3) Analyzed habitat and distribution data from the
rangewide survey (Saalfeld et al. 2008).
(4) Designed, and planning to conduct in 2009-2010,
a BBS-based monitoring survey in portions of
South Dakota, North Dakota, and Montana (SLJ
and N. Niemuth, pers. comm.).
(5) Conduct research on various aspects of the life
history and ecology (Hartman and Oring 2006a,
b; Oring 2006).
(6) Established a Long-billed Curlew ListServ.
(7) Established a web site to exchange current
reports on Long-billed Curlew research (http://
www.fws.gov/mountain%2Dprairie/species/birds/
longbilled%5Fcurlew/).
(8) Convened two workshops to discuss Long-billed
Curlew conservation and status (LaCrosse,
Wisconsin, in 2002 and Boulder, Colorado, in
2006). These workshops were attended by a wide
range of agencies, organizations, and individuals.
Participants at these meetings developed strate-gies
and recommendations for specific actions
needed to achieve the conservation of the species.
In some cases, lead agencies, partners, and costs
have been identified; in many cases, the scope
of the action is unknown and will only be known
after initial development of projects have been
completed (Table 2.1).
(9) A third workshop is planned for the 2009 West-ern
Hemisphere Shorebird Group meeting in
México. It is hoped that this meeting will provide
an opportunity for researchers from México to be
involved, to share their research, and to further
implement the identified priority wintering and
migration needs.
22 Status Assessment and Conservation Action Plan for the Long-billed Curlew (Numenius americanus)
Introduction
This chapter presents the individual status
assessments for U.S. and Mexican states and
Canadian provinces where Long-billed Curlews are
currently found in large numbers (Table 1.1). State
and provincial status, along with information about
ocurrence are given. Status assessments have been
combined where Long-billed Curlews have either
been extirpated (Illinois, Indiana, Iowa, Michigan,
Minnesota, and Wisconsin) or have only a few
wintering or migrating individuals yearly (Alabama,
Florida, Georgia, Louisiana, Mississippi, North
Carolina, and South Carolina).
No status assessment is included for the Canadian
province of Manitoba; breeding Long-billed Curlews
have been extipated from this province and there is
no information available.
Most of the accounts for México were developed
from materials submitted for the Western
Hemisphere Shorebird Reserve Network’s
(WHSRN) site-based conservation plan project.
Individual state status assessments have not
been included for the states of Chiapas, Durango,
Guanajuato, Guerrero, Morelos, Oaxaca, Querétaro,
Quintana Roo, Yucatán, Zacatecas, or the Distrito
Federal, since data are sporadic and largely
anecdotal. No records of Long-billed Curlews
occurring in Aguascalientes, Campeche, Hidalgo,
Estado de México, Michoacán, Puebla, San Luis
Potosí, Tabasco, and Tlaxcala were found.
The status assessments presented here all follow the
same format. Where no information is available or is
not relivant to the state or province that section may
be omitted. Many of the states and provinces have
limited information on Long-billed Curlews and this
is reinforced in these summaries.
Chapter 3: State and Provincial Summaries of
Long-billed Curlew Status
Long-billed Curlew chick with transmitter. Cory Gregory©. Long-billed Curlew. Cory Gregory©.
Chapter 3: State and Provincial Summaries of Long-billed Curlew Statu s 23
United States
Arizona
Summary: Long-billed Curlews are a rare breeder
in Arizona. The only breeding recorded was in 1993
in the White Mountains area. It is an uncommon
to locally and irregularly common migrant and is
generally rare to locally uncommon in winter in
southern Arizona, but is possibly increasing.
Status:
State: Long-billed Curlews do not have a state
designated status.
Natural Heritage Rank: Arizona rank S1B
(Critically Imperiled Breeder), S3S4N (Vulnerable
to Apparently Secure Nonbreeding); National rank:
N5N, N5B (Secure Nonbreeding, Breeding); Global
rank: G5 (Secure; NatureServe 2006).
Trends:
North American Breeding Bird Survey (BBS)
trends and abundance data: Long-billed Curlews
were not detected on any routes (Sauer et al. 2008).
Christmas Bird Count (CBC): The first Arizona
CBC was conducted in 1910, with 1-7 counts
conducted irregularly into the 1960’s. Number of
count circles gradually increased from then to the
2005 level of 33 circles. Curlews were undetected in
69 years out of the 85-year history of Arizona CBC.
First recorded on a CBC in 1975 (1 individual).
Fewer than 10 recorded in 11 of the years since then.
Peak numbers were from the years 1986 (90 birds,
Elfrida CBC), 1988 (74 birds; 71 Elfrida CBC, 2 Gila
River CBC, 1 Patagonia CBC), 2003 (122 birds; 106
Gila River CBC, 15 Elfrida CBC, 1 elsewhere) and
2005 (81 birds, Gila River CBC). Recorded in 6 of
the 10 years from 1996 to 2005 (National Audubon
Society 2006). The increase in occurrence may be
due to greater observer coverage and knowledge
of where to look for them rather than actually
representing a true increase in winter numbers.
Range:
Breeding: One pair with three small young were
located approximately 2.4 km west of Eagar, Apache
County on 21 June 1993 at approximately 2176 m
elevation, for the first and only confirmed breeding
in the state (Corman and Wise-Gervais 2005).
Additional summer observations have occurred
within a few miles of Eagar since 1993. Two pairs
were also seen displaying approximately 6.4 km west
of Eagar near a prairie-dog town in April 2006 (T. E.
Corman, pers. comm.). Breeding is also suspected
near the Springerville/Eagar airport, where adults
were observed mobbing a Ferruginous Hawk (Buteo
regalis) by the airport in either 1994 or 1995 (T. E.
Corman, pers. comm.). Big Lake, Apache County
may represent another potential breeding location.
Historically, one individual was observed in late
June 1915 (Goldman 1926); a pair was also observed
in this area in mid-June 1993 (Corman and Wise-
Gervais 2005).
Migration:
Approximate timing: Spring migrants arrive
in the lower Colorado River Valley in early March,
peaking in April; small numbers persist through
May and early June. Fall numbers start increasing
in mid-June and could represent fall migrants or
failed breeders. Their numbers peak from mid-
July through early September and numbers are
less through mid-October (Rosenberg et al. 1991).
Records suggest migration peaks in March and July;
most of these observations are from outside the
lower Colorado River Valley (eBird 2008).
Location of staging areas: Long-billed
Curlews occur statewide in appropriate habitats but
are most numerous in the lower Gila and Salt River
Valleys and along the lower Colorado River. There
are no known predictable staging areas.
Numbers, particularly high counts:
Maximum counts are of 124 near Mesa (Maricopa
County) on 3 April 1952 and 125 at the same location
on 12 March 1964 (Monson and Phillips 1981); 190
were reported at San Luis (Yuma County) on 28
September 1974 (Rosenberg et al. 1991).
Winter:
Approximate timing: Long-billed Curlews
are found throughout the winter in Arizona.
Locations: Most consistent in the Gila
River Valley from Phoenix downstream to the
lower Colorado River Valley in Yuma County (T.
E. Corman, pers. comm.). They are also recorded
regularly in the Arlington Valley near Buckeye and
on the Paloma Ranch near Gila Bend (Maricopa
County). They are occasional but not annual in
higher-elevation agricultural fields in the Sulphur
Springs Valley of southeastern Arizona (e.g. near
Elfrida, Cochise County) and occasionally found
elsewhere.
Numbers, particularly high counts: 106,
Gila River CBC, 27 December 2002; 140 in Arlington
Valley on 26 December 2005 (T. E. Corman, pers.
comm.); “several hundred” wintering near Yuma in
recent years (H. Detwiler, pers. comm.).
Abundance and Population: There has only been
one documented case of breeding in Arizona.
Habitat: Long-billed Curlews in Arizona primarily
are found below 305 m elevation in agricultural
fields, especially in flooded fields or cut-over alfalfa
fields during winter. They use “fields” (Monson and
Phillips 1981), plowed or grassy agricultural fields,
and are occasionally observed roosting on sandbars
and lakeshores (Rosenberg et al. 1991) during
migration.
Threats: Threats include loss of grasslands
through conversion to agriculture or urbanization.
Submitted by William H. Howe
Reviewed by Troy E. Corman
24 Status Assessment and Conservation Action Plan for the Long-billed Curlew (Numenius americanus)
California
Summary: Long-billed Curlews occur in California
year round, with lowest numbers in May, but status
varies considerably seasonally and regionally. The
breeding population is relatively small and restricted
to the northeastern region of the state. California
is an important area for wintering and migrating
curlews, with the lowland areas in the interior of the
state supporting the bulk of the population, likely
between 10,000-20,000 individuals. Important areas
to wintering and migrating curlews in the interior of
the state include the Central Valley, Imperial Valley,
and Carrizo Plain. Agricultural land, particularly
dry and irrigated pastures, alfalfa fields, and post-harvest
rice fields, are the most important inland
habitats in winter and migration. Several thousand
curlews occur on the California coast during fall
migration and in winter; primary coastal habitats
are wetlands, beaches, and (locally) pastures.
Urbanization of agricultural land, changing
agricultural practices, and intake of contaminants
such as pesticides and herbicides are potential
serious threats. Overall trends in curlew populations
in California are unknown, and the species is poorly
monitored in the state.
Status:
State: No official status. Formerly considered
a California Bird Species of Special Concern
(California Department of Fish and Game 1992),
but no longer given this designation (Shuford and
Gardali 2008).
Natural Heritage Rank: California rank: S2
(Imperiled); National status: N5B, N5N (Secure
Breeding, Nonbreeding); Global rank: G5 (Secure;
NatureServe 2006).
Trends: Overall trends in curlew populations in
California are unknown.
North American Breeding Bird Survey (BBS)
trends and abundance data: Trend and relative
abundance are analyzed from 8 routes in California.
Relative abundance equaled 0.57 individual per
route. Data suggest a positive trend in California
from 1966-2007; however, the trend is not
significant (22.8% per year; P = 0.48; Sauer et al.
2008). Credibility of the BBS is poor, with a BBS
Credibility Indicator equal to Red (data have
important deficiency, such as low abundance and low
sample size; Sauer et al. 2008). The BBS may include
data from the Central Valley, where curlews do not
breed, and the June timing of the BBS overlaps with
Long-billed Curlew nonbreeding movements (G. W.
Page, W. D. Shuford, and C. M. Hickey, pers. comm.).
Christmas Bird Count (CBC): Statewide, the
number of Long-billed Curlews reported per party-hour
has increased on the CBC from 1960-1961
through 2005-2006 (National Audubon Society 2006).
However, this is associated with an increase from 14
to about 40 in the number of CBC circles reporting
Long-billed Curlews (National Audubon Society
2006). The available analyses on the Audubon
website are not sufficient to assess recent trends in
winter curlew abundance in California.
Range:
Breeding:
Approximate timing: Small numbers of
Long-billed Curlews breed from April to July in
northeastern California.
Breeding atlas or lat-long locations: Not
available.
Counties recorded: Inyo, Lassen, Modoc,
Mono, Plumas, Shasta, Sierra, and Siskiyou (G. W.
Page, W. D. Shuford, and C. M. Hickey, pers. comm.).
Migration: During migration, Long-billed Curlews
occur widely in California, particularly along the
coast, in the Central Valley, in the western Great
Basin, and in the southern deserts.
Approximate timing: Spring migration
generally extends from mid-March through mid-
April. Fall migration occurs primarily from mid-July
through mid-October. Peak numbers are seen in
early spring, from 1 March through 1 April and
in the post-dispersal period 1 July through 15
November (eBird 2008). Patten et al. (2003) reported
fall migration peaks in the Imperial Valley in July
and August.
Location of staging areas: Because Long-billed
Curlews occur at many of the same coastal
and inland locations in fall, winter, and spring, it is
difficult to distinguish if there are migratory staging
areas and if so, whether they differ from wintering
areas. Further obscuring knowledge of staging areas
is that small numbers of non-breeding curlews spend
the summer in the same areas where they migrate
and winter (G. W. Page, W. D. Shuford, and C. M.
Hickey, pers. comm.).
Numbers, particularly high counts: Patten
et al. (2003) reported 7,890 curlews on 28 July 1987
and Shuford et al. (2004) also reported 7,476 on a
single day in August 1995 in the Salton Sink. The
numbers of curlews migrating in autumn is around
10,000-20,000 individuals (G. W. Page, W. D. Shuford,
and C. M. Hickey, pers. comm.).
Winter: Long-billed Curlews are present along
the coast from Humboldt to San Diego counties
and in the interior of the state in the Central Valley,
Imperial Valley, and Carrizo Plain (Fig. 3.1). Small
numbers of birds also winter locally in valleys within
the Coast Ranges and in the southern California
deserts.
Approximate timing: Wintering birds
begin arriving 21 June in the Elk River estuary of
Humboldt Bay (Colwell and Mathis 2001) where
about 300 curlews are resident from June to April
(Colwell 2006). Females arrive as early as late June,
with males and juveniles arriving later (Colwell
2006). Individual birds typically depart to breeding
areas in early April (Colwell 2006). In other areas,
departure from wintering areas extends from late
March to early May (Jurek 1973), with the majority
Chapter 3: State and Provincial Summaries of Long-billed Curlew Statu s 25
of birds departing in the first half of April (Shuford
et al. 1989).
Abundance and Population: Anecdotal
observations and data from broad-scale and site-specific
surveys suggest the breeding population is
around 100-200 pairs (G. W. Page, W. D. Shuford, and
C. M. Hickey, pers. comm.). The numbers of curlews
migrating in autumn statewide are probably around
10,000 individuals (G. W. Page, W. D. Shuford, and C.
M. Hickey, pers. comm.). The wintering population
ranges from 1000-5000 individuals on the coast (Page
et al. 1999) and is likely 10,000-20,000 individuals
inland. Statewide CBC early winter totals from
1995-1996 to 2005-2006 averaged 7838 individuals
(sd = 2013; National Audubon Society 2006). The
highest and second highest totals were 11,082 (2004-
2005) and 10,666 individuals (1995-1996; G. W. Page,
W. D. Shuford, and C. M. Hickey, pers. comm.).
Habitat:
Breeding: At Lower Klamath NWR, Siskiyou
County, Long-billed Curlew nests were found in
various low grass-forb communities (Brown 1986).
Also, there are anecdotal observations of breeding
in heavily grazed pastures, wet meadows, and salt
grass (W. D. Shuford, pers. comm.).
Migration: On the coast, Long-billed Curlews
are found in wetlands, on beaches, and in grassy
areas. In the interior, curlews forage primarily on
agricultural lands. Roosts of curlews have been
found at water treatment ponds, agricultural waste
water ponds, managed wetlands, and saline lakes
(Shuford et al. 2002b, 2004).
Winter: Primary foraging habitats are tidal
mudflats, sloughs, and salt marshes in coastal
wetlands (Stenzel et al. 1976, Colwell and Mathis
2001, Colwell et al. 2002), wet pastures (Colwell
2006) and some outer coast beaches (Lehman
1994). At low tide, curlews aggregate on bay tidal
flats (Colwell 2006); at one site with particularly
high curlew densities, 10-15 curlews were recorded
defending low-tide feeding territories ranging in
size from 0.2-4.7 ha. The residency of individual
curlews varies greatly (12-71% of 130 daily low tide
observations made between June-April; Colwell
2006). Winter rains create supplemental foraging
habitats in pastures adjacent to the bay, where
they feed on earthworms and other invertebrates
(Colwell 2006).
Non-wetland habitats used near the coast include
wet and dry pastures and grasslands (Colwell
and Mathis 2001), sewage ponds, and active and
fallow agricultural fields (Shuford et al. 1989). In
the Central Valley, curlews forage on agricultural
lands including dry and irrigated pastures, dry and
flooded post-harvest rice fields (Elphick and Oring
1998), alfalfa and other hay fields, fallow fields, and
occasionally tilled fields (G. W. Page, W. D. Shuford,
and C. M. Hickey, pers. comm.). In the Imperial
Valley, curlews favor agricultural fields (Patten et
Figure 3.1. Christmas Bird Count data for the California region for 2002-2003 (National Audubon Society
2006).
26 Status Assessment and Conservation Action Plan for the Long-billed Curlew (Numenius americanus)
al. 2003). Along the Salton Sea shore, they roost in
shallow impoundments (Patten et al. 2003, Shuford
et al. 2004).
Monitoring: Monitoring has included Point Reyes
Bird Observatory’s (PRBO) 1988-1994 surveys
of coastal and interior wetlands in California and
PRBO’s 1971-2006 counts of wintering waterbirds
at Bolinas Lagoon in Marin County. Habitat and
geographic coverage by these surveys was not
widespread enough to determine population size or
trend for Long-billed Curlews in California.
Research: Because of the large numbers of
indiviuals wintering in California, most work has
focused on non-breeding birds, particularly at
the northern limit of the species’ winter range
in Humboldt Bay (Colwell 2006). Other research
in California has been on diet, particularly in
coastal wetlands (Stenzel et al. 1976, Colwell and
Mathis 2001, Leeman et al. 2001), and wintering
territory habitat use and spacing (Colwell and
Mathis 2001, Colwell et al. 2002). Only one study
has been completed on seasonal abundance, nest
site characteristics, and timing of curlew nesting in
California (Brown 1986).
Long-billed Curlews establish and defend
nonbreeding feeding territories in coastal wetlands
(Colwell 2006), with the number of territorial
curlews declining from fall into winter (Colwell and
Mathis 2001). Curlews feed for similar proportions
of time in summer (84%) and winter (88%). Summer
diets differed because curlews ate many bivalves
on 2 of 8 territories; diets also differed in numbers
of shrimp, crabs, and worms. During winter, diets
were similar among three territories (Colwell et al.
2002). Further work has examined the importance,
use and distribution of non-breeding curlews, in a
coastal estuary (Mathis et al. 2006), in rain-soaked
pastures in the coastal environment (Leeman and
Colwell 2005), and in post-harvest rice fields in the
Sacramento Valley (Elphick and Oring 1998).
Further research on wintering habitats, timing
and use; breeding natural history; and effects of
contaminants are important areas of research for the
conservation of Long-billed Curlews in California.
Conservation Activities (ongoing): None specific
to Long-billed Curlews.
Threats: Loss of habitat, including agricultural land
to urbanization, and changing agricultural crops
and practices are pressing threats. Pesticide and
herbicide contamination, excessive grazing, and
disturbance are other potential threats in California
(G. W. Page, W. D. Shuford, and C. M. Hickey, pers.
comm.).
Submitted by Gary W. Page, W. David Shuford, and
Catherine M. Hickey
Revised by Stephanie L. Jones
Reviewed by Mark A. Colwell and Susan M. Thomas
Colorado
Summary: Long-billed Curlews breed in the Central
Shortgrass Prairie Region of eastern Colorado.
Although there currently are no monitoring,
conservation, or management activities specifically
aimed at curlews, they may benefit from some of the
grassland nesting bird initiatives and activities being
conducted throughout the state.
Status:
State: Long-billed Curlews are a Species of
Concern in Colorado and have been ranked as a Tier
I Species of Greatest Conservation Need (Colorado
Division of Wildlife 2006).
Natural Heritage Rank: Colorado rank: S2B
(Imperiled Breeding); National rank: N5N, N5B
(Secure Nonbreeding, Breeding); Global rank: G5
(Secure; NatureServe 2006).
Trends:
North American Breeding Bird Survey (BBS)
trends and abundance data: Long-billed Curlews
are reported on 15 routes. Relative abundance
equals 1.24 birds per route. Data suggest a
nonsignificant negative trend from 1966-2007
(-6.0%/yr; P = 0.22) within Colorado. Credibility of
the BBS is poor, with a BBS Credibility Indicator
equal to Yellow (data have a deficiency such as low
abundance, low sample size, or significantly different
sub-interval trends; Sauer et al. 2008).
Christmas Bird Count (CBC): Long-billed Curlews
are not present in Colorado during winter (Andrews
and Righter 1992).
Long-billed Curlew. Cory Gregory©.
Chapter 3: State and Provincial Summaries of Long-billed Curlew Statu s 27
Range:
Breeding: Long-billed Curlews are found primarily
in the Central Shortgrass Prairie as well as on the
Front Range, Southern Rocky Mountains, and
Wyoming Basin regions of Colorado (Colorado
Division of Wildlife 2006). The Colorado Breeding
Bird Atlas (Kingery 1998) documented the highest
statewide density of breeding curlews in extreme
southeastern Colorado, in Baca and Las Animas
Counties, primarily east of the Purgatoire River.
Relatively high breeding density also occurs north
of the Arkansas River, from El Paso and Pueblo
Counties, east to the Kansas border. Lower densities
of curlews occur sporadically throughout east-central
and northeastern Colorado (Kingery 1998).
There are few West Slope records (Bailey and
Niedrach 1967). Low densities of breeding curlews
likely exist in northwestern Colorado as breeding
was suspected in Moffat and Mesa counties (Kingery
1998). Surveys conducted in 2004 and 2005 by Rocky
Mountain Bird Observatory documented curlews
only in southeastern Colorado (Sparks et al. 2005,
Sparks and Hanni 2006).
Approximate timing: Kingery (1998)
provided limited information on phenology.
Courtship activity was reported as early as 19 April.
Nesting activity was reported primarily in May and
June. Fledged young were reported as early as 11
June and as late as 15 July. King (1978) observed
mating activities between 12-15 April but thought
that they were nearing completion.
Breeding atlas or lat-long locations:
Evidence of breeding in Colorado was documented
primarily on the eastern plains of Colorado (Kingery
1998). Breeding evidence was “confirmed” in 24 atlas
blocks, “probable” in 21 blocks, and “possible” in 33
blocks.
Migration: Andrews and Righter (1992) described
Long-billed Curlews as a rare spring and fall
migrant in western valleys, mountain parks, and
on the eastern plains of Colorado. They are regular
migrants along the reservoirs in eastern Colorado
(Bailey and Niedrach 1967). No large staging areas
are recorded.
Abundance and Population: Breeding population
was estimated at 943-3233 individuals based
on Breeding Bird Atlas data (Kingery 1988).
Populations are thought to have declined from
historical levels, but few data are available to
estimate the size of the historical or current
population.
Surveys conducted by Rocky Mountain Bird
Observatory in 2003 did not produce a sufficient
number of observations of Long-billed Curlew
in Colorado to estimate density within the study
area (Hanni and McLachlan 2004). During 2005, a
graduate research project was designed to estimate
occupancy and abundance of rare grassland
breeding birds in eastern Colorado (H. C. Tipton,
pers. comm.). Occupancy surveys conducted
between 1 May and 30 June resulted in detection
of Long-billed Curlews on 18 of 282 randomly
selected plots. Abundance surveys conducted 19
May through 6 June using double-observer sampling
methods resulted in the detection of seven Long-billed
Curlews on a total of six of the 282 plots. Data
were insufficient to estimate occupancy, abundance,
or density of Long-billed Curlews in eastern
Colorado (H. C. Tipton, pers. comm.). Colorado was
one of 16 western states involved in the 2004-2005
Rangewide Long-billed Curlew Breeding Survey
conducted by the U.S. Fish and Wildlife Service and
the U.S. Geological Survey. During the two-year
survey, twenty-one 32-mile long road-based routes
were run within the state’s known breeding range.
Long-billed Curlews were not detected during the
survey on any of the routes (SDF). None of the
above-mentioned survey programs were designed to
specifically provide population estimates for curlews
in Colorado.
Habitat: Long-billed Curlews are found primarily
on shortgrass prairies, playas, and in open water.
They also use mixed-grass prairies, dryland and
irrigated crops, Eastern Plains rivers and streams,
grass- and forb-dominated wetlands, and sand dune
complex grasslands (Colorado Division of Wildlife
2006). They Curlews were observed in highest
densities within native prairie on sites with 3%
or less shrub cover (Hanni and McLachlan 2004).
During a study of breeding grassland birds in
eastern Colorado in 2005, Long-billed Curlews were
observed using grassland, dryland agriculture, and
prairie dog colony plots (H. C. Tipton, pers. comm.).
Monitoring: There are no current Long-billed
Curlew-specific monitoring programs in Colorado.
Section-based surveys were conducted by Rocky
Mountain Bird Observatory in 2003-2006 throughout
the shortgrass prairie region in Colorado (Hanni
and McLachlan 2004, Sparks et al. 2005, Sparks and
Hanni 2006). Long-billed Curlews were observed
during these surveys; however, the number of
observations were low and the section-based
monitoring program is likely inadequate to monitor
population trends of this species.
Based on survey projects conducted between 2003
and 2005, the following recommendations were made
for future monitoring of curlews in eastern Colorado:
1) employing a stratified sampling frame and/or
one with unequal inclusion probabilities to increase
sample size within the core curlew habitat while still
sampling throughout the plains but at a relatively
lower intensity; 2) tailoring plot size to Long-billed
Curlew biological requirements; 3) timing occupancy
visits closely together in May; and 4) do not survey
on roads (H. C. Tipton, pers. comm.). However,
based on data from the 2004-2005 rangewide survey
(Jones et al. 2008) surveys would be more effective
if conducted during mid-April in eastern Colorado
to coincide with the local preincubation period. No
obvious road-bias was demonstrated during the
2004-2005 rangewide survey (Stanley and Skagen
2007).
28 Status Assessment and Conservation Action Plan for the Long-billed Curlew (Numenius americanus)
Research: King (1978) investigated habitat use
of breeding Long-billed Curlews in Baca County.
She was able to document breeding behavior, time
of nesting, nest characteristics, and habitat use by
breeding and foraging Long-billed Curlews.
Conservation Activities (ongoing): There are no
Long-billed Curlew specific conservation activities in
Colorado at this time. Several specific conservation
actions have been suggested to maintain and
restore habitat and address other threats within
the state (Colorado Division of Wildlife 2006).
Avoiding destruction of large tracts of native
prairie, providing incentives such as conservation
easements, re-seeding with native, site-appropriate
species, and use of compatible grazing management
practices will help protect breeding habitat for
Long-billed Curlews. Restoring playas and reducing
groundwater pumping will also have wide-ranging
benefits to wildlife in the region.
Threats: Colorado Division of Wildlife (2006)
assessed threats and concluded Long-billed Curlews
were subjected to disturbance from motorized
and non-motorized recreation and proximal non-recreation
sources, habitat loss due to conversion of
grasslands to cropland and native shortgrass prairie
degradation, and general water pollution as well as
concerns about pesticide spraying and run off.
Management: There are no Long-billed Curlew
specific management actions currently taking
place in Colorado. For nesting curlews, the Playa
Lakes Joint Venture has developed habitat
recommendations based on population objectives
and modeling efforts. These efforts call for an
increase in acreage of large blocks of shortgrass
prairie with a focus on central eastern Colorado and
the counties north of the South Platte River (Playa
Lakes Joint Venture Landbird Team 2007). Their
habitat recommendations include: 1) large blocks of
grasslands at least 530 ha in size, 2) located within
1.6 km of a water source, 3) less than 81 ha of shrub,
4) less than 8 ha of woodlands, and 5) less than 20 ha
of roads (Playa Lakes Joint Venture Landbird Team
2007).
Submitted by Suzanne D. Fellows and
David S. Klute
Reviewed by Heather C. Tipton
Idaho
Summary: There are low numbers of breeding Long-billed
Curlews found in the state. Sporadic short
term monitoring projects have been conducted.
Idaho researchers were among the earliest to look
at breeding biology, productivity, and habitat needs
in Long-billed Curlews. As in most parts of their
range, habitat loss is the biggest threat; however
disturbance from recreational vehicles has also been
documented.
Status:
State: Long-billed Curlews are classified as a
Species of Greatest Conservation Need in the Idaho
Comprehensive Wildlife Conservation Strategy
(Idaho Department of Fish and Game 2005).
Natural Heritage Rank: Idaho rank: S3B
(Vulnerable Breeding); National rank: N5N, N5B
(Secure Nonbreedin