This week’s Bird of the Week, compliments of the Weminuche Audubon Society and Audubon Rockies, is the eared grebe.
Grebes are birds designed for life on and under the water. They can compress their thick, waterproof feathers against the body to aid in diving by making themselves less buoyant. With legs and lobed feet set far back on the body, they are awkward on land but excellent divers.
In breeding plumage, this small grebe has a peaked black head, and black neck and back. Its sides are cinnamon-colored and eyes are red. It is named for the fan of golden feathers extending out behind the eyes. Nonbreeding birds are grayish black.
Of the more than 20 species of grebes, the eared grebe is the most abundant in the world. It is also one with some strange behaviors. Of all birds that are capable of flight, it is the one that remains flightless for the longest portion of its life. Cycles that involve gorging and fasting which occur three to six times a year result in eared grebes spending 9 to 10 months each year incapable of flight.
During these cycles, eared grebes double their body weight when their digestive organs grow and fat accumulates while their pectoral flight muscles shrink. When it’s time to move on, sometimes not until food sources are depleted, they can quickly reverse this process to allow for flight.
They breed in shallow wetlands of North America whose locations frequently shift with the availability of water. In freshwater they eat a variety of insects, mollusks, crustaceans and a few small fish. They capture prey by diving, pecking at the surface of water or dipping their heads only underwater. Like other grebes, they sometimes eat their own feathers and even feed some to chicks to aid in digestion.
During both spring and fall migrations, eared grebes stop at saline lakes to fatten up on brine shrimp and alkali flies. Mono Lake in California and Great Salt Lake in Utah serve as important staging grounds during stopovers to and from breeding grounds. There have been times when eared grebe numbers at Great Salt Lake have been estimated at 2.5 million. Along with Wilson’s phalaropes, their fate is closely tied to the health of these western saline lakes.
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