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Desert Wildlife -
American AvocetRecurvirostra americana
DISTRIBUTION, ABUNDANCE, AND SEASONALITY
A common to abundant winter visitor to salt ponds, fresh and saline emergent wetlands, and mudflat habitats throughout the Central Valley and the central and southern coastal areas. Breeds from March to mid-July, and is relatively common during this period in northeast California, the Central Valley, and coastal estuaries (Cogswell 1977). Common most of the year at the Salton Sea, but only a few pairs have been known to nest (Garrett and Dunn 1981).
SPECIFIC HABITAT REQUIREMENTS
Feeding: Forages on mudflats, salt or alkali flats, in shallow ponded areas with silt bottoms, and in salt ponds (Hamilton 1975, Cogswell 1977). Feeds by probing in mud, sweeping bill through water or soupy mud, or by swimming and tipping-up like ducks. Preferred foods include aquatic insects, crustaceans, snails, worms, and occasionally seeds of aquatic plants (Cogswell 1977).
Cover: May flock together during storms on the leeward side of levees and dikes for cover (Rigney and Rigney 1981).
Reproduction: Primary nesting habitats are relatively barren islands in salt ponds or alkali lakes, levees, dikes, or untravelled road beds, near feeding areas. Also may nest on salt flats or in wet meadows (Bent 1927, Gibson 1971, Cogswell 1977). Nest is a simple scrape 0.5 to 3 cm (0.2 to 1.2 in) deep on the top of a levee, or on an island or salt flat. Nest usually lined with vegetation or small pebbles.
Water: No additional data found.
Pattern: For breeding, depends upon relatively undisturbed levees and islands within or near feeding areas, on estuarine salt ponds, or other estuarine or inland shallow-water impoundments or lakes.
SPECIES LIFE HISTORY
Activity Patterns: Yearlong, diurnal activity, except migration apparently is nocturnal (Gibson 1971).
Seasonal Movements/Migration: A portion of the central coast wintering population is migratory, moving inland to the Central Valley, northeastern California, and eastern Sierra Nevada in mid-March to breed. A somewhat smaller population (600-800 pairs) is resident in the San Francisco Bay area (Gill 1973, Rigney and Rigney 1981).
Home Range: No additional data found.
Territory: Gibson (1971) identified 3 types of territories during different periods in the nesting cycle. Prior to egg laying, territory was centered around feeding area. During incubation, both the nest and a secondary feeding area 50-130 m (162-422 ft) in diameter were defended. Once the eggs hatched, adults defended an area 20-100 m (65-325 ft) in diameter centered around chicks.
Reproduction: Peak egg-laying is April, and hatching occurs from early to mid-June. Three or 4 eggs laid; average 3.7 per nest (Gibson 1971). Single-brooded; both parents incubate the eggs for 22-24 days (Harrison 1978). Precocial young are mobile within 3-4 hr after hatching. Defended by both adults, and family remains intact for about 25 days (Harrison 1978).
Niche: Nests are subject to flooding if water levels in salt ponds are raised.
Bent, A. C. 1927. Life histories of North American shorebirds. Part 1. U.S. Natl. Mus. Bull. 142. 420pp. Cogswell, H. L. 1977. Water birds of California. Univ. California Press, Berkeley. 399pp. Ehrlich, P. R., D. S. Dobkin, and D. Wheye. 1988. The birder's handbook. Simon and
Schuster, New York. 785pp. Garrett, K., and J. Dunn. 1981. Birds of southern California. Los Angeles Audubon Soc. 408pp. Gibson, F. 1971. The breeding biology of the American avocet (Recurvirostra americana) in central Oregon. Condor 73:444-454. Gill, R. E., Jr. 1973. The breeding birds of the South San Francisco Bay estuary., M.A. Thesis, San Jose State Univ., San Jose, CA. 145pp. Hamilton, R. B. 1975. Comparative behavior of the American avocet and the black-necked stilt (Recurvirostridae). Ornithol. Monogr. No. 17. 97pp. Harrison, C. 1978. A field guide to the nests, eggs and nestlings of North American birds.
W. Collins Sons and Co., Cleveland, OH. 416pp. Harrison, C. J. O., ed. 1978. Bird families of the world. Harry N. Abrams, Inc., New York. 264pp.
Rigney, M., and T. Rigney. 1981. A breeding bird survey of the South San Francisco Bay salt pond levee system. U.S. Dep. Inter., Fish and Wildl. Serv., San Francisco Bay Natl. Wildl. Refuge Special Rep. 130pp.
Life history accounts for species in the California Wildlife Habitat Relationships (CWHR) System were originally published in: Zeiner, D.C., W.F.Laudenslayer, Jr., K.E. Mayer, and M. White, eds. 1988-1990. California's Wildlife. Vol. I-III. California Depart. of Fish and Game, Sacramento, California. Updates are noted in accounts that have been added or edited since original publication.
Written by: M. Rigney
Reviewed by: L. Mewaldt
Edited by: E. Beedy, R. Duke
Adults have long legs, a rust head and neck, a long up-turned bill and a white lower body with a distinctive
black and white pattern on the wing and back.
Their breeding habitat is marshes, prairie ponds, and shallow lakes in the mid-west and on the Pacific coast of North America. They nest on open ground, often in small groups, sometimes with other waders.
They are migratory and most winter on the southern Atlantic and Pacific coasts of Mexico and the United States.
These birds forage in shallow water or on mud flats, often sweeping their bills from side to side in water. They mainly eat crustaceans and insects.