thumb|Calls recorded in Palo Alto, California
The American avocet (Recurvirostra americana) is a large wader in the avocet and stilt family, Recurvirostridae, found in North America. It spends much of its time foraging in shallow water or on mud flats, often sweeping its bill from side to side in water as it seeks crustacean and insect prey.
Taxonomy
The American avocet was formally described in 1789 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae. He placed it with the pied avocet in the genus Recurvirostra and coined the binomial name Recurvirostra americana. Gmelin based his description on that by the English ornithologist John Latham who in 1785 had described and illustrated the American avocet in his A General Synopsis of Birds. Latham cited the earlier publication by William Dampier and also that by Thomas Pennant. The genus name combines the Latin meaning 'bent' or 'curved backwards' with meaning 'bill'. The species is monotypic: no subspecies are recognised.
The American avocet is a member of the order Charadriiformes, which includes shorebirds, gulls, and alcids. Its family, Recurvirostridae, includes stilts and avocets. The genus Recurvirostra includes three other species: the Andean avocet, the pied avocet, and the red-necked avocet. The bill is black, pointed, and curved slightly upwards towards the tip. It is long, surpassing twice the length of the avocet's small, rounded head. Like many waders, the avocet has long, slender legs and slightly webbed feet. The legs are a pastel grey-blue, giving it its colloquial name, blue shanks. The plumage is black and white on the back, with white on the underbelly. During the breeding season, the plumage is brassy orange on the head and neck, continuing somewhat down to the breast. After the breeding season, these bright feathers are swapped out for white and grey ones. The avocet preens its feathers, commonly considered to be a comfort movement. Avocets use three distinct calls: common call, excited call, and broken wing call.
Behavior and ecology
Breeding
The American avocet breeds in anything from freshwater to hypersaline wetlands in the western and mid-west United States. After reaching their breeding grounds, the avocets quickly establish territory in pairs. American avocets are also known to have parasitized other birds' nests. Time spent caring for newborn chicks equates to that spent incubating. The newborns are precocial, able to walk and capable of feeding themselves. The young are expected to begin flying four to five weeks after hatching.
Food and feeding
The American avocet tends to prefer habitats with fine sediments for foraging. In the winter, it feeds extensively on brine shrimp. Usually, this entails the avocet pecking while walking or wading on the shore, but it can also swim to expand foraging area. During the breeding season, avocets continue to eat brine shrimp but switch mainly to consuming brine flies. Brine flies and brine fly larvae are so abundant in avocet breeding grounds that they often blacken the surface of any exposed mud. Brine flies sustain the avocet during its breeding season. The avocet employs both visual and tactile methods of feeding.
Threats and conservation status
thumb|John James Audubon's depiction of the American avocet in breeding plumage
Shooting and trapping of American avocets led to population decline until the 1900s. During this time, the species was extirpated from most of the East Coast of the United States.
In culture
In his famous The Birds of America, John James Audubon describes a day of stalking and spying on the avocet. He judiciously noted their foraging, nesting, defensive, and flight behaviors.