The eared grebe (Podiceps nigricollis) is a small waterbird in the podicipedidae family. They are found across North America and Eurasia in freshwater lakes and marshes. Eared grebes breed in colonies across these regions during the summer months before migrating south to overwinter. Their breeding and wintering ranges span a large portion of the Northern Hemisphere.
Breeding Range
Eared grebes breed across a large portion of North America and Eurasia. Their breeding grounds extend from western Europe across Russia and Siberia to Alaska and Canada.
In North America, they breed from central Alaska across central Canada to the Great Lakes region and into the northern Great Plains states. Their range extends southward along the Pacific coast to southern California and the southwest United States.
Some key areas where they breed in North America include:
- Central and Western Alaska
- Throughout much of the Canadian provinces
- Northern Great Plains including Montana, North Dakota, and Minnesota
- Great Lakes region including Michigan, Wisconsin, and Minnesota
- Pacific Northwest including British Columbia and Washington
In Eurasia, eared grebes have an extensive breeding range stretching from western Europe across Russia to Siberia. Key breeding areas include:
- Iceland, Scotland, Scandinavia
- Russia including western Siberia
- Mongolia and northern China
They breed in small colonies on freshwater lakes and marshes across these regions. Shallow lakes with extensive emergent vegetation are prime nesting habitat.
Breeding Habitat
Eared grebes require shallow freshwater lakes and marshes for breeding. They nest in colonies along the edges of emergent vegetation like cattails and bulrushes. Ideal breeding lakes are shallow (1-6 ft deep) with abundant submerged and emergent aquatic vegetation. These wetlands provide food resources as well as cover from predators.
Some key aspects of eared grebe breeding habitat include:
- Shallow freshwater lakes and marshes
- Abundant emergent vegetation like cattails
- Submerged aquatic vegetation
- Adjacent mudflats for foraging
- Areas protected from wind and waves
Nesting colonies can number from just a few pairs up to a few hundred pairs. Nests are floating platforms anchored to emergent vegetation in shallow water near wetland edges.
Wintering Range
During the winter months, eared grebes migrate from their breeding grounds to ice-free lakes and coastlines across North America and Eurasia. Their winter range extends along the Pacific and Gulf coasts of North America and scattered lakes further inland.
In North America, the bulk of the wintering population is concentrated along the Pacific Coast. Huge numbers winter in the San Francisco Bay and along the coast of California south into Mexico. Other important wintering areas include:
- Gulf Coast of Texas and Mexico
- Chesapeake Bay
- Great Lakes
- Colorado River basin
Smaller numbers remain further inland on large lakes if they remain ice-free.
Across Eurasia, eared grebes winter along the coasts of Europe and Asia. Important wintering regions include:
- Coastal Western Europe including the United Kingdom
- Black Sea and Mediterranean Coast
- Persian Gulf
- Japan and Korea
They are mostly found in marine habitats during winter, especially near estuaries and bays. But some will utilize freshwater lakes in milder regions.
Winter Habitat
While they nest in freshwater wetlands, eared grebes move to more saline habitats in the winter. Their winter habitat includes both marine and freshwater sites.
Coastal marine waters are a major winter habitat, especially estuaries and bays. These areas provide ample food resources for the winter. Grebes forage in shallow waters and intertidal mudflats.
Some key aspects of their winter habitat include:
- Marine – estuaries, bays, coastlines
- Freshwater lakes and reservoirs if ice-free
- Shallow, protected waters
- Intertidal mudflats and sandbars
Even on marine waters, eared grebes prefer areas with some emergent vegetation for cover. They also utilize inland lakes that remain unfrozen.
While concentrated along the coasts, some birds do winter on inland lakes. Major wintering lakes include the Great Lakes and reservoirs along the Colorado River.
Migration
Eared grebes undergo migratory journeys of up to 3,000 miles between their breeding and wintering grounds. They travel across large expanses of North America between nesting sites and wintering grounds.
In North America, northern breeders migrate southward in the fall through the Central Flyway. This routes them through the interior of the continent towards winter sites along the Gulf Coast and southern California. Routes follow major river valleys southwards.
Birds breeding along the Pacific Coast follow routes within the Pacific Flyway. They travel shorter distances to reach coastal California and Mexico.
North American migration occurs September through November in the fall and March through May in spring. Exact timing varies by region and population.
Eurasian birds follow similar broad front migrations moving south and southwest from breeding areas towards the Mediterranean, Black Sea, Persian Gulf and East/South Asia.
Eared grebes travel in flocks during migration, sometimes joining with other grebe species. Flight is direct and fast with rapid wing beats.
Population and Conservation
Global population estimates place the total eared grebe population at approximately 5 million breeding adults. In North America, Partners in Flight estimate 1.5 million breeding adults. They are considered a species of low conservation concern due to this large population.
Their numbers fluctuate locally based on habitat conditions in breeding wetlands. While still common, some populations have declined from historical levels due to wetland drainage and degradation. Conservation of key breeding and staging wetlands is important for maintaining populations.
While an overall abundant species, eared grebes face threats from:
- Wetland loss and degradation
- Disturbance at nesting colonies
- Fluctuating water levels
- Exposure to pesticides and contaminants
Monitoring breeding populations, protecting wetland habitats, and managing water levels are conservation priorities to maintain stable eared grebe populations into the future.
Conclusion
In summary, the eared grebe can be found across a large swath of North America and Eurasia. Their breeding grounds center on shallow freshwater marshes across Alaska, Canada, and northern Eurasia. They migrate long distances to winter along coastlines and unfrozen lakes. While still abundant, conservation of wetland habitats is important for this waterbird. Their specialized habitat needs and long migrations make them vulnerable to habitat changes across continents. Maintaining a network of suitable wetlands will help conserve eared grebe populations into the future.