The Whimbrel (Numenius phaeopus) is a large shorebird that breeds in subarctic areas and migrates long distances to wintering grounds across the world. Understanding the flight path of the Whimbrel provides important insights into shorebird migration ecology and conservation. This article will explore what is known about the migration routes, stopover sites, timing, and flight speed of the Whimbrel.
Breeding Range
The Whimbrel breeds in subarctic tundra habitats across North America and Eurasia. The main breeding range extends from western and central Alaska across northern Canada to Hudson Bay. Smaller numbers breed along the coasts of Maine and the Canadian Maritimes. In Eurasie, breeding occurs from Norway across northern Russia and Siberia to Chukotka.
Key breeding areas include:
- Western and northern Alaska
- Central and eastern Canadian Arctic
- Hudson Bay lowlands
- Northern coast of Norway
- Northern Russia and Siberia
The tundra provides ideal habitat, with wetlands and ponds surrounded by open areas with low vegetation. Nesting occurs in elevated mounds of grasses and sedges near water. After breeding, Whimbrels gather in large flocks along coastal areas before migrating south.
Fall Migration
The southbound fall migration begins in late July and August. Whimbrels depart the breeding grounds and fly long distances to reach wintering areas. There are three main flyways used during fall migration:
Atlantic Flyway
Many Whimbrels migrating from eastern Canada and Greenland head south over the Atlantic Ocean. Birds follow coastlines south along Greenland, eastern Canada, and the eastern U.S. Key stopover sites include James Bay, the Bay of Fundy, and the mid-Atlantic coast. Some birds stage in large numbers on the beaches of Cape Cod before crossing the ocean.
Interior North American Flyway
Whimbrels from central Canada and Alaska travel south through the interior of North America. They stop to rest on lakes and wetlands across the Prairie Provinces, Great Plains, and Great Basin. Significant stopover sites include Quill Lakes (Saskatchewan), Red Rock Lakes (Montana), Great Salt Lake (Utah), and the Klamath Basin (Oregon/California).
Pacific Flyway
Many Whimbrels follow coastlines south from Alaska along the Pacific Coast. Important stopover sites where Whimbrels concentrate in high numbers include Copper River Delta (Alaska), Skagit Flats (Washington), Grays Harbor (Washington), and Humboldt Bay (California).
Wintering Range
The Whimbrel winters primarily along coastlines from the southeastern U.S. south across the Caribbean and along the coasts of Central and South America. Key wintering regions include:
- Southeastern U.S. from North Carolina to Texas
- Caribbean Islands
- Central America from Mexico to Panama
- Coasts of Colombia and Venezuela
- Coasts of northeastern Brazil
Whimbrels concentrate on beaches, mudflats, mangroves, and estuaries where they forage on fiddler crabs, marine worms, and other invertebrates. A smaller number of Whimbrels winter inland across floodplains and savannas in southern South America.
Spring Migration
In March and April, Whimbrels begin the long northbound migration back to the breeding grounds. They follow the same flyways and stopover sites used in fall. Spring migration starts earlier in South America and progresses northward as the season advances.
Key aspects of spring migration:
- Early departures from Caribbean and South America in March
- Stopovers along Atlantic coast in April
- Arrivals in Hudson Bay lowlands by mid May
- Arrivals on Alaskan breeding grounds by late May
The Whimbrel is one of the earliest shorebird migrants, appearing in the Arctic just after snowmelt exposes the first open tundra.
Migration Speed and Distances
The Whimbrel is capable of very long distance nonstop flights during migration. Some key metrics:
- 5,000-7,000 km nonstop flights
- 200+ km/hr flight speeds
- 4-6 day nonstop flights between breeding and wintering areas
- 8,000-10,000 km one-way migration distances
These long flights are aided by favorable winds, stored fat reserves, and the ability to enter torpor to reduce energy consumption.
However, Whimbrels also require stopovers to rest and feed. Shorter flights of 1,000-2,000 km occur between stopovers where birds replenish energy reserves. The combination of nonstop long-distance flights and shorter hops with stopovers enables the Whimbrel to complete its hemispheric migrations.
Threats and Conservation
The Whimbrel faces a number of threats on its migration routes and in both breeding and wintering habitats. These include:
- Habitat loss in breeding areas due to climate change
- Disturbance and habitat degradation at migration stopover sites
- Sea level rise reducing wintering habitat
- Overhunting on Caribbean islands
Protecting key stopover habitats and mitigating climate change impacts are priorities for conserving Whimbrel populations. Regular surveys at sites across the flyways also help monitor Whimbrel numbers and distribution.
Conclusion
The Whimbrel is a champion migrator, flying vast distances over oceans and continents between its Arctic breeding grounds and wintering areas dispersed across the Americas. Conservation of this iconic shorebird depends on maintaining the wetland and coastal habitats required along its flyways and at either end of its remarkable migratory journeys. Understanding the flight paths, stopovers, and migration ecology of the Whimbrel can help inform management efforts to protect this long-distance traveler.