The largest bird migration occurs over Alaska. Each spring and fall, billions of birds from around the world migrate through Alaska as they travel between their breeding and wintering grounds. This incredible phenomenon is known as the great Alaska migration.
When does the great Alaska migration occur?
The Alaska bird migration happens twice a year, in the spring and fall. The spring migration occurs from late April to early June. During this time, birds are traveling north from their winter homes in the tropics to their summer breeding grounds in Alaska and other northern regions. The fall migration takes place between August and October as the birds return south for the winter.
Why do birds migrate through Alaska?
Alaska provides critical resting and feeding habitat for migrating birds. Its strategic location along migratory flyways and abundant food resources make it an ideal place for birds to stop during their long journeys. Alaska acts as a land bridge connecting Asia and North America, funneling birds through as they travel between continents.
Which species migrate through Alaska?
Over 200 bird species migrate through Alaska, including:
- Shorebirds like plovers, sandpipers, and phalaropes
- Waterfowl such as geese, swans, and ducks
- Raptors including peregrine falcons, gyrfalcons, and golden eagles
- Songbirds like warblers, sparrows, and thrushes
How many birds pass through Alaska during migration?
It’s estimated that around 5-6 billion birds migrate through Alaska annually. While exact numbers are difficult to determine, some astounding migration statistics for Alaska include:
- Up to 80% of the world’s Pacific black brant population, or 160,000-180,000 birds, pass through the Yukon-Kuskokwin Delta
- Up to 1 million shorebirds stop over at the Copper River Delta
- Around 120 million birds have been recorded migrating along the Arctic Coastal Plain per season
Major migration routes through Alaska
There are five major flyways that birds follow through Alaska:
- The Pacific Flyway along the southern coastline
- The Central Flyway through interior and northern Alaska
- The Arctic Coastal Plain Route above the Arctic Circle
- The Cordova Route through Prince William Sound
- The Southeast Coastal Route along the Alaska panhandle
Pacific Flyway
The Pacific Flyway follows Alaska’s southern coastline along the Aleutian Islands and the Alaska Peninsula. Many waterbirds like geese, swans, cranes, and ducks use this route.
Central Flyway
The Central Flyway passes through central and northern Alaska crossing the Brooks Range, Yukon River, and Arctic Foothills. Shorebirds, raptors, and songbirds utilize this path.
Arctic Coastal Plain
This route follows Alaska’s northern coast along the Beaufort and Chukchi seas. It is used by shorebirds and waterfowl that breed in the Arctic tundra.
Cordova Route
The Cordova Route passes through Prince William Sound and the Copper River Delta, which support huge shorebird concentrations.
Southeast Coastal Route
The Southeast Coast Route extends along Alaska’s panhandle through coastal fjords and islands. Sea birds and songbirds often follow this path.
Major stopover sites in Alaska
Alaska has many important stopover areas that provide food and rest for migrating birds. Some key sites include:
- Yukon Delta National Wildlife Refuge – Supports millions of waterfowl and shorebirds yearly. Largest site in Alaska.
- Copper River Delta – Critical shorebird stopover with peak numbers up to 1 million birds.
- Bristol Bay – Key stop for shorebirds, waterfowl, gulls, and terns migrating along the Pacific Flyway.
- Stikine River Delta – Diverse mix of waterbirds, raptors, and songbirds stop here.
- Cook Inlet – Supports several million shorebirds and waterfowl annually.
Threats birds face during migration through Alaska
Migrating birds face many threats and challenges on their journeys through Alaska including:
- Habitat loss from development, resource extraction, and climate change
- Disturbance from human activity near migration sites
- Exhaustion if birds cannot find enough food at stopovers to refuel
- Severe weather events that may blow birds off course
- Pollution from oil spills or contaminants
- Collisions with vehicles, buildings, or communication towers
Conservation efforts in Alaska
Many conservation initiatives aim to protect migratory birds in Alaska including:
- Establishing wildlife refuges and protected migration corridors
- Monitoring programs to track bird populations and trends
- Regulations limiting development and human disturbance
- Habitat restoration projects, especially along coastlines
- Education campaigns to raise awareness of migration challenges
Conclusion
In summary, Alaska hosts the largest bird migration in the world each year as billions of birds traverse the state between their wintering and breeding grounds. A variety of species follow routes along Alaska’s coasts, through its wetland deltas and river valleys, and across mountain ranges. Key stopover sites provide crucial rest and refueling habitat. However, birds face many threats during their journeys through Alaska and conservation efforts are ongoing to protect this amazing natural phenomenon.