Birds of Srilanka (Part 1)

Grabes


Grebes are small to medium-large in size, have lobed toes, and are excellent swimmers and divers. However, although they can run for a short distance, they are prone to falling over, since they have their feet placed far back on the body.

Grebes have narrow wings, and some species are reluctant to fly; indeed, two South American species are completely flightless. They respond to danger by diving rather than flying, and are in any case much less wary than ducks. Extant species range in size from the Least Grebe, at 120 grams (4.3 oz) and 23.5 cm (9.3 inches), to the Great Grebe, at 1.7 kg (3.8 lbs) and 71 cm (28 inches).

Grebes have unusual plumage. It is dense and waterproof, and on the underside the feathers are at right-angles to the skin, sticking straight out to begin with and curling at the tip. By pressing their feathers against the body, grebes can adjust their buoyancy. Often, they swim low in the water with just the head and neck exposed.

In the non-breeding season, grebes are plain-coloured in dark browns and whites.However, most have ornate and distinctive breeding plumages, often developing chestnut markings on the head area, and perform elaborate display rituals. The young, particularly those of the Prosodics genus, are often striped and retain some of their juvenile plumage even after reaching full size.


When preening, grebes eat their own feathers, and feed them to their young. The function of this behaviour is uncertain but it is believed to assist with pellet formation , and to reduce their vulnerability to gastric parasites.

Grebes make floating nests of plant material concealed among reeds on the surface of the water. The young are precocial, and able to swim from birth.