Aythya americana

Description

This large diving duck gets its name from the male's chestnut-red head, which looks similar to that of the canvasback. Unlike the canvasback, however, the male redhead has a high, up-and-downish forehead. His feet are bluish gray, and his eyes are orange-yellow. The head of the female is a yellowish brown that is somewhat darker on the crown. She has a slight pale ring around her brown eyes, and her feet are bluish in color. Both the male and female have a pale blue bill with a white ring around the black tip.

Distribution and Habitat

Redheads range from southern Canada to the northern United States (Washington to Maine). Some populations breed in the prairie pothole region of the northern Great Plains; there are also some breeding populations in central Alaska. Their winter range extends from California to the southern Atlantic Coast and south into central Mexico. They are found on shallow freshwater lakes, ponds, and marshes, so long as the body of water is at least 28 inches deep so that the ducks can dive; they are also found on brackish and coastal bays and lakes.

Reproduction

Courtship is initiated by the female. Pairing begins in late winter, but courtship behavior may continue into the spring. The male deserts the female as soon as eggs are laid.

Nesting begins in midsummer, in marshes and prairie potholes. Nest sites may be located on dense vegetation over water, on islands, or on dry land. If the nest is on land, water must be nearby. If at all possible the female will build her nest from hardstem bulrush and cattails.

Three types of egg-laying behaviors have been observed among redheads. "Normal" egg-laying involves the hen laying and incubating her own eggs in her own nest. "Semiparastic" egg-laying entails the hen laying her eggs in more than one nest, none of which are built by her. "Parasitic" egg-laying occurs when the hen lays her eggs in another redhead's nest after incubation has occurred. The parasitic female's eggs will probably not hatch, however, because they are off schedule from the other eggs.

Hens usually lay one egg a day, but may skip a few days before the entire clutch is laid.

Redheads are known for the early desertion of their young, as the mother leaves the ducklings as soon as they are able to fly.

Diet

Redheads feed primarily on vegetable matter obtained from the bottom of a body of water. They will also take mollusks from the bottom, and will occasionally dabble on the surface of shallow marshes for insects.

Habits and Behaviors

Redheads migrate south in September and return north in March. They migrate in V-formations at great speeds, flying for long distances in the morning and evening.

Redheads are normally found singly, in pairs, or in flocks up to 15 birds. At popular wintering areas, however, they can be found by the hundreds, and sometimes thousands.

When settled in deep water, a flock of redheads may suddenly rise into the air en masse for no apparent reason.

Scientific Classification

phylum Chordata
subphylum Vertebrata
class Aves
order Anseriformes
family Anatidae
subfamily Anatinae
genus & species Aythya americana

Animal Diversity Web http://animaldiversity.org/accounts/Aythya_americana/

Canvasback

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