The long-billed curlew (Numenius americanus) is a large shorebird that breeds primarily on the prairies and fields of the interior West and migrates through the Great Plains to wintering grounds on the coasts of Mexico and Central America. Measuring up to 2 feet long with a wingspan of over 3 feet, the long-billed curlew is the largest North American shorebird. It is easily identified by its long, thin, downward-curving bill.
Long-billed curlews were once abundant across the shortgrass and mixed-grass prairies of the Great Plains. However, the conversion of native prairie to cropland over the past century has dramatically reduced curlew breeding habitat. The long-billed curlew is currently listed as a species of conservation concern at both the state and federal levels due to significant population declines and ongoing threats. Understanding the geographic distribution and habitat requirements of long-billed curlews is critical for developing effective conservation strategies for this iconic grassland bird.
Breeding Range and Habitat
The core breeding range of the long-billed curlew centers on the shortgrass prairies of the western Great Plains in states such as Colorado, Wyoming, Montana, South Dakota, Nebraska, New Mexico, and Texas. Smaller breeding populations occur in the interior valleys of the Northwest in areas such as eastern Washington, eastern Oregon, southern Idaho, and northern Nevada.
Long-billed curlews typically nest in expansive open landscapes with abundant short grasses and scattered shrubs. Favorite nesting habitats include shortgrass prairie, desert grasslands, shrubsteppe, grazed mixed-grass prairie, hayfields, fallow fields, and pastures. The presence of elevated nest sites such as mounds, hummocks, or cow patties is also important. Curlews avoid nesting in areas with tall, thick vegetation or dense woody cover. Access to wetlands, streams, or irrigated fields providing foraging habitat with an abundance of grasshoppers, beetles, and other invertebrate prey is also key.
State | Estimated Breeding Population |
---|---|
Colorado | 5,000-10,000 pairs |
Wyoming | 1,000-2,000 pairs |
Montana | 500-1,000 pairs |
South Dakota | 500-1,000 pairs |
Nebraska | 500-1,000 pairs |
New Mexico | 500-1,000 pairs |
Texas | 100-500 pairs |
Oregon | 100-500 pairs |
Idaho | 100-500 pairs |
Nevada | 100-500 pairs |
Utah | 100-500 pairs |
North Dakota | 50-100 pairs |
Washington | 50-100 pairs |
Oklahoma | 50-100 pairs |
Arizona | 50-100 pairs |
Kansas | 10-50 pairs |
California | 1-10 pairs |
Key Breeding Areas
Some of the most important breeding areas for long-billed curlews include:
– Shortgrass prairie of southeastern Colorado, including Comanche and Pawnee National Grasslands
– Mixed-grass prairie of northern Montana
– Shrubsteppe of southern Idaho
– High plains and interior valleys of Wyoming
– Malheur National Wildlife Refuge in eastern Oregon
– Grasslands and wetlands of western Nebraska’s Sandhills region
– Desert grasslands of the Chihuahuan Desert in southern New Mexico
– Shortgrass prairie of the Texas Panhandle
Migration Routes
Long-billed curlews undertake a lengthy migration between their breeding grounds on the Great Plains and wintering areas along the coasts of Mexico and Central America. After breeding, curlews start migrating south in July. They follow central flyways through the Great Plains and into Texas, converging on the coast of the Gulf of Mexico.
Curlews make frequent stopovers to rest and feed in interior wetlands, agricultural fields, and salt flats along the migration route. Major stopover sites include Cheyenne Bottoms Wildlife Area in Kansas, Great Salt Lake in Utah, the Rainwater Basin of Nebraska, and coastal habitats along the Texas Gulf Coast.
From the Texas Gulf Coast, most long-billed curlews make a nonstop flight across the Gulf of Mexico to wintering grounds in Mexico. A smaller number migrate overland into northeastern Mexico or down through Central America. Satellite tracking studies have documented curlews migrating between breeding sites in Idaho and wintering sites along Mexico’s Yucatan Peninsula – a distance of over 3,000 miles.
Key Migration Stopover Sites
Some of the most important stopover areas used by migrating long-billed curlews include:
– Cheyenne Bottoms Wildlife Area, Kansas
– Buffalo Lake National Wildlife Refuge, Texas
– Quivira National Wildlife Refuge, Kansas
– Audubon National Wildlife Refuge, North Dakota
– San Luis Valley, Colorado
– Rainwater Basin, Nebraska
– Great Salt Lake, Utah
– Summer Lake Wildlife Area, Oregon
– Gray’s Lake National Wildlife Refuge, Idaho
– Copper River Delta, Alaska
Wintering Range
Nearly the entire population of long-billed curlews winters along the Pacific and Gulf coasts of Mexico and Central America. The highest concentrations occur along Mexico’s Gulf Coast between Tamaulipas and Veracruz. Smaller numbers winter along Mexico’s Pacific coast from Sonora to Chiapas. Central American wintering sites extend from Guatemala through Costa Rica.
Preferred wintering habitats include coastal sand flats and beaches, coastal prairies, estuarine sandbars and mudflats, salt evaporation ponds, shrimp farms, and wet agricultural fields. Wintering curlews often forage in mixed flocks with other shorebirds. Key food resources include fiddler crabs, marine worms, and brine shrimp.
Major Wintering Sites
Important wintering sites for long-billed curlews include:
– Laguna Madre, Tamaulipas, Mexico
– Marismas Nacionales, Nayarit, Mexico
– Bahía Santa María, Sinaloa, Mexico
– Lago Cuitzeo, Michoacán, Mexico
– Bahía de Banderas, Jalisco, Mexico
– Laguna Ojo de Liebre, Baja California Sur, Mexico
– Golfo de Fonseca, Honduras
– Golfo de Nicoya, Costa Rica
– Manglares de Tumbes National Reserve, Peru
Threats and Conservation
The long, steady decline of the long-billed curlew stems from widespread habitat loss and degradation on the breeding grounds, migration routes, and wintering areas. Major threats include:
– Conversion of grasslands and prairies to cropland
– Habitat fragmentation from energy development, roads, and urban sprawl
– Alteration of river flows impacting wetland stopover habitats
– Disturbance and predation on breeding and wintering grounds
– Reduced juvenile survival from loss of wetlands and nesting habitat
Various conservation actions aimed at curlew recovery include:
– Protecting and restoring native prairie and wetland habitats
– Managing public lands for curlew breeding habitat
– Increasing protected coastal wintering habitat in Mexico and Central America
– Working with private landowners to implement curlew-friendly grazing and farming practices
– Conducting landbird conservation planning across the full annual life cycle
– Continuing population monitoring, tracking studies, and research
– Raising public awareness and supporting funding for curlew conservation
The continued decline of the long-billed curlew illustrates the urgent need for collaborative conservation partnerships across the species’ vast migration route from the Northern Great Plains to Mexico and Central America. Safeguarding remaining grassland and coastal habitats will be key to ensuring the future of this iconic, long-distance migrant.
Conclusion
In summary, the long-billed curlew breeds primarily on the shortgrass prairies and interior valleys of the western Great Plains, migrates through the Central Flyway along the Great Plains to the Texas Gulf Coast, and winters almost entirely along the coasts of Mexico and Central America. Population declines due to widespread habitat loss underscore the need for collaborative conservation efforts across the curlew’s breeding range, migration route, and wintering grounds. Protecting grassland and coastal habitats as well as working with private landowners to implement curlew-friendly land management will be essential to recovering long-billed curlew populations. Understanding the geographic distribution and habitat requirements of long-billed curlews across their full life cycle is key to guiding effective conservation planning and action for this sensitive species.