Great grebe

Appearance

This is a very large grebe, with proportions more like a goose or a cormorant than a typical grebe. They range in length from 67 to 80 cm and usually weigh about 1,600 grams, but can scale to at least 2 kg. They are buffy-rufous on the neck and chest, blackish on the back and have a whitish belly. The head is sooty gray with a reddish-brown eye. Due to its size and unique coloration, the great grebe is unlikely to be confused with any other bird, including other grebes.

Habitat

This species occurs mainly in open waterways. Most birds are seen on low altitude lakes and sluggish rivers, as well as estuarine marshes. While breeding, it frequents the heavily vegetated inlets off of large lakes. Outside of the breeding season, most birds will move to estuaries and bays, usually heavy with kelp. Non-breeding birds may live along the coasts all year.

These birds are widespread and common through most of their range. Much of their native habitat has not been cleared, especially in the southern portions of their range.

Reproduction

After living in groups numbering up to the hundreds, these birds move inland to breed. Most populations lay their eggs from October to January, becoming later further south. In the isolated Peru population, nesting occurs in September and October, with a possible second clutch in January or February. They are moderately social when breeding, occasionally forming colonies. Three to five eggs are laid. Two broods, or possibly more, can be raised at the same time.

Food

The great grebe lives on a diet mostly of fish, sometimes over 11 cm long, but usually smaller. Prey competition can occasionally occur with the neotropic cormorant over fish, but that species usually takes larger fish. Also insects, crustaceans and mollusks are taken. The diet can switch to almost half crabs during the wintertime along the coasts, and these birds can also take the young of other waterbirds, especially coots.