Measurements
Both Sexes
- Length
- 16.9–18.5 in
43–47 cm - Wingspan
- 28.3 in
72 cm - Weight
- 9.7–12.3 oz
275–350 g
Other Names
- Foulque d'Amérique (French)
- Avoceta Americana, Piqocurvo (Spanish)
Cool Facts
- In response to predators, the American Avocet sometimes issues a series of call notes that gradually changes pitch, simulating the Doppler effect and thus making its approach seem faster than it actually is.
- Nesting American Avocets aggressively attack predators, sometimes physically striking Northern Harriers or Common Ravens.
- A female American Avocet may lay one to four eggs in the nest of another female, who then incubates the eggs. American Avocets may parasitize other species' nests too; single American Avocet eggs have been found in the nests of Mew Gulls. Other species may also parasitize avocet nests. Avocets have incubated mixed clutches of their own eggs and those of Common Terns or Black-necked Stilts. The avocets reared the stilt hatchlings as if they were their own.
- American Avocet chicks leave the nest within 24 hours after hatching. Day-old avocets can walk, swim, and even dive to escape predators.
Habitat
Marsh
Shallow fresh and saltwater wetlands.
Food
Insects
Aquatic invertebrates.
Nesting
Nesting Facts
- Clutch Size
- 3–4 eggs
- Egg Description
- Greenish brown with irregular dark spots. Pointed on one end.
- Condition at Hatching
- Downy and able to walk.
Nest Description
A scrape in the ground, lined with grass or other vegetation, feathers, pebbles, or other small objects, or completely unlined.
Nest Placement
Ground
Behavior
Probing
In its pre-copulation display, the male American Avocet preens himself with water, gradually gaining intensity to the point of frenzied splashing just before he mounts the female. After copulating, the pair intertwines their necks and runs forward.In territory establishment and in self-defense, performs elaborate ritualized displays. One notable display involves two pairs, or a pair and a third individual, facing each other in a circle and then stretching their bills toward each other. Upon the approach of a terrestrial predator, may approach the predator with a teetering gait and outstretched wings, as if on a tightrope. Also crouches on the ground as if incubating, only to move and crouch again in a new location.Feeds in shallow water, while wading or swimming. Locates food by sight and snaps it up, or sweeps its long bill through the water, capturing prey by touch.
Conservation
Least Concern
Populations declined in the 1960s and 1970s, largely from the loss of wetlands from water diversion for human use. Contamination of wetland habitat with selenium caused increased developmental abnormalities and mortality. Since 1995, owners of selenium-contaminated sites in northern California have been required to provide safe wetland habitat for the species. Breeding success on the newly created sites has been much greater than initially expected, but long-term prospects for breeding at these sites are not clear.
Credits
- Robinson, J. A., L. W. Oring, J. P. Skorupa, and R. Boettcher. 1997. American Avocet (Recurvirostra americana). In The Birds of North America, No. (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA., No. 275 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and the American Ornithologists' Union, Washington, D.C.