Grebes look like ducks and loons but their nearest kin are flamingos
Grebes swim low, dive for food and resemble loons, so for a long time scientists grouped the two together. That turned out to be convergent evolution. Molecular studies, backed by at least eleven shared anatomical quirks, now point to a far stranger relative: the flamingo.
The family holds 22 living species, from the least grebe at about 120 g to the great grebe at 1.7 kg. Their scientific name joins Latin words for rear end and foot, because the legs sit so far back on the body. That placement makes them superb swimmers and clumsy walkers that tend to topple over on land. Instead of fully webbed feet they have broad lobes on each toe, which slice forward with little drag and spread wide on the backstroke, pushing the bird along rather as a frog kicks.
Their feathers are remarkable. An average grebe carries about 20,000 of them, a count beaten only by the tundra swan and the emperor penguin, packed so densely on the belly that they feel like fur. No birds spend more effort on grooming, coating their plumage with a waxy gland oil that repels water and parasites. Oddly, grebes eat their own feathers and feed them to their chicks, possibly to help form pellets and shield the gut from sharp fish bones. By pressing feathers against the body, they can adjust how high they float.
Flying is not their strength. Many must patter across the water to take off, and several species living on stable lakes have become flightless, with shrunken wings and larger bodies. Courtship, by contrast, is spectacular: many pairs dance in perfect synchrony across the surface before building a floating nest of vegetation.
The flamingo link is written in odd details, such as both groups laying eggs with a chalky coating. True grebes appear suddenly in fossils 23 to 25 million years ago, probably originating in the Southern Hemisphere. Today about a third of species face conservation concern from habitat loss, poaching and introduced predatory fish, and three have already gone extinct.
Source: Grebe
