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American Avocet

Recurvirostra americana

Avocet

Decription

The tallest and longest-legged bird in its family, the American avocet is 17-18 inches long. It is also the only avocet with distinct breeding and non-breeding plumages. Breeding plumage is obtained in the first year and is a rusty cinnamon along the head and neck, while basic plumage is a gray head. Adult breeding plumage appears from January to March and is lost in July to September. Both plumages feature very prominent black-and-white patterns. Other prominent features are an obviously upturned black bill and light blue legs. Females are similar to males except for a shorter and more upwardly-curved bill; the male's bill is almost straight.

Distribution and Habitat

American avocets are found throughout the western United States, south through Mexico into Central America. A migratory species, the majority of individual avocets travel relatively short distances to their winter habitats compared to other shorebirds, but small flocks have been known to winter along the east coast of the United States as far north as North Carolina, as well as on Cuba and other Caribbean islands.

districution of the American avocet

The preferred habitat includes ponds, freshwater marshes, mud flats, and flooded fields, but American avocets are also found on lakeshores, rocky and sandy seashores, bay and coastal islands, and tidal flats.

Reproduction

Breeding season runs from April through June, during which several dozen pairs will share a common nesting ground. American avocets are monogamous during the breeding season, but mating pairs do not appear to reform from year to year. Mating is acompanied by an elaborate ceremony that involves various crouching and bowing postures in and out of water, dancing with outspread wings, and swaying from side to side. The mating itself usually occurs in the water.

The nest is a shallow depression on a beach or mudflat, usually lined with bits of dry grass. Up to 8 eggs are laid at intervals of 1-2 days, with 4 being the average-sized clutch. The eggs are pale ashy-yellow or olive-brown in color, covered evenly with dark brown spots and blotches. Both parents share incubation duties, which last 22-24 days.

Chicks can leave the nest almost immediately after hatching. They are protected by both parents, but must find their own food. Fledging takes 28-35 days, and total independence is reached at about 10 weeks of age.

Diet

American avocets swoop their open bills back and forth in shallow water to take in food. In deep water they will "tip up" like dabbling ducks. While aquatic insects form the largest part of their diet, a variety of other small aquatic inertebrates are taken, and they will also feed on aquatic vegetation and seeds.

Other Habits and Behaviors

Outside of the breeding season American avocets may gather in flocks of several hundred and feed in dense groups.

Usually fairly quiet, they become extremely aggressive on breeding and nesting grounds and will protest loudly and dive bomb when intruders approach.

Scientific Classification

Phylum Chordata
Subphylum Vertebrata
Class Aves
Order Charadriiformes
Family Recurvirostridae
Genus & Species Recurvirostra americana

SOURCE
Animal Diversity Web animaldiversity.org/accounts/Recurvirostra_americana/

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The Robinson Library >> Science >> Zoology >> Birds >> Order Charadriiformes

This page was last updated on July 25, 2017.