The Eared Grebe
WOULD YOU BELIEVE THIS WETLANDS PARK VISITOR IS RELATED TO THE FLAMINGO?
It’s really true – recent DNA analysis shows grebes (Podiceps nigricollis) and flamingoes are close relatives! I don’t know about you, but I would never have guessed. Appearances certainly can deceive!
Eared grebes are the most abundant grebe species in the world, ranging across western North America and in the Old World, from Europe and the British Isles to the Near East, Africa, India, and Pakistan. A common winter visitor, eared grebes at Clark County Wetlands Park are members of the population that breeds in shallow alkaline inland ponds and marshes throughout the interior of the western United States and Canada.
These small grebes have thin, upturned bills, high, rounded backs, red eyes, and fluffy, almost “tail-less” appearance. When swimming, they paddle along with lobed feet similar to those of coots, appearing to be lower in the water at the “head” than the “tail” end. They may also hide below the water’s surface by compressing air trapped in their feathers and simultaneously squeezing it out of their internal air sacs, sinking until only their heads are exposed.
At the Park, we usually see them in their winter plumage – gray below and black above, with red eyes popping against their black heads and clean white collars. In summer, they trade the white collar for a black neck, exchange their gray undersides for golden brown, and add wispy golden feathers across the sides of their heads that look like somewhat like ears. These seasonal wardrobe changes give them both of their common names: eared grebe, for the golden feather “ears,” and black-necked grebe, from the black neck.
Migrating eared grebes undergo a truly strange annual cycle of physical changes. During the nesting season, the grebes dive and feed on the surface of the water, capturing mostly aquatic beetles, dragonfly larvae, flies, and mayflies, along with some crustaceans, mollusks, tadpoles, and small fish to feed their nestlings. However, during the autumn migration season (August to October), almost every eared grebe in North America leaves its summer nesting colony to congregate in one of two locations: the Great Salt Lake, Utah, or Mono Lake, California. There, the grebes feast on brine shrimp that thrive in these saline lakes, consuming about 30,000 shrimp per bird every day, with a sprinkling of alkali flies!
While they fatten in preparation for their fall migration (south or southeast to coastal California and Mexico or to the Gulf Coast), their digestive organs enlarge and their flight muscles shrink until they can no longer fly. About three weeks before migration, the process reverses, with flight muscles enlarging and digestive organs shrinking in readiness for their night flights to wintering areas. This process of alternating “atrophy and hypertrophy” occurs three to six times a year in eared grebes. They are actually unable to fly for nine to ten months of the year – the longest flightless period known for any bird that can fly at all.
The great fall concentrations of eared grebes at only two locations raises concern for what could happen to them if those vital migration staging areas were lost. The Great Salt Lake, for example, is now less than 29% of its former surface area and shrinking steadily. Concern for the saline lakes of the Great Basin (including Great Salt Lake and Mono Lake) has led to the recent passage of national legislation sponsored by the National Audubon Society. Under the Saline Lake Ecosystems in the Great Basin Act, scientific monitoring and assessment programs will hopefully protect and preserve the saline lake staging areas vital to the incredibly specialized eared grebe, and to other migratory waterfowl.
Stay tuned and keep an eye out for floating eared grebes as you walk the Park trails!
– By Chris Leavitt, President; photo by David Walker
Please enjoy these YouTube videos!
Eared Grebes Swimming
A Beautiful Black Necked Grebe Diving and Feeding