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AMERICAN WIGEON
Anas americana American Wigeon, known to hunters as "baldpates," nest from the Arctic Ocean south to the southern Rocky Mountains. Because of the varied habitats within the summer and winter ranges of these ducks, wigeon are adapted to utilize a variety of behaviors to supply their nutritional needs. They feed in winter and migration mostly on leaves, stems and seeds of aquatic and terrestrial vegetation. They are better adapted to grazing on land than other surface-feeding ducks. Their terrestrial foods range from grass to waste grain in farm fields. On the water wigeon may be closely associated with American Coot (Fulica americana) and diving ducks, from whom wigeon often steal plant materials gathered below the reach of dabblers like wigeon. On their breeding grounds their diet shifts to more seeds, fruits and aquatic insects (Mowbray 1999). DISTRIBUTION. During the 1987-1992 field work seasons of the TBBA project, observers found a single probable breeding site in El Paso County and 2 possible records on the Rolling Plains (see the region map in Lockwood and Freeman [2004]). These authors describe wigeon as local in the summer, especially in the Panhandle, with no evidence of nesting. Atlasers in Oklahoma found no breeding evidence for American Wigeon in that state (Reinking 2004). Most wigeon in North America breed from central Alaska across northern Canada to Hudson Bay and south into the United State to the Pacific Northwest, Rocky Mountains and northern Great Plains. Highest breeding densities of the wigeon are in the western Canadian Prairie Provinces, the Mackenzie Delta and Old Crow Flats in the northern Yukon and Northwest Territories. Winter populations of these ducks are largest in the Pacific Northwest, throughout the Central Valley of California and southern high plains of Texas and New Mexico. Some wigeon also winter in Mexico, Central America and the West Indies (Stiles and Skutch 1989, Howell and Webb 1995, Am, Ornithol. Union. 1998, Mowbray 1999). SEASONAL OCCURRENCE. American Wigeon are common to abundant migrants and winter residents of Texas, especially on the |
s8- |
playa lakes
of the High Plains, one of the more important wintering areas for this
species.
Most of these ducks depart in March with the last leaving in May.
Fledgling American Wigeon were observed by atlasers in Colorado
from July 7 to August 18, suggesting a breeding season for Texas would
start no
later than May. Fall migrants have been reported as early as
September 6 with most present by early October (Oberholser 1974,
Leukering and
Kingery 1998, Mowbray 1999, Lockwood and Freeman 2004). BREEDING HABITAT. Colorado atlasers found about 60% of fledged young of American Wigeon on lakes without emergent vegetation, about 20% on open water swamps and the rest on water with floating or emergent plants (Leukering and Kingery1998). Nests of these ducks are usually a hollow in dry ground, often a considerable distance from water in brushy grasslands. The hollow is lined with dry grass, plant stems and pale gray down feathers. More down feathers are added during incubation. In this nest the female usually lays 8-9 (range 3-11) deep cream to nearly white, unmarked eggs, indistinguishable from those of the Gadwall (Anas strepera). Incubation by the female lasts 22-25 days. The male usually abandons her during this time. After hatching the precocial young leave the nest with their mother within 24 hours. She leads them to water, usually within 0.5 km (0.3 mi) of the nest site and broods them until they reach at least pre-flight size. The ducklings feed themselves by dabbling and surface gleanings and are capable of flight from 37-48 days after hatching, depending on latitude. One brood is raised per year (Harrison 1979, Mowbray 1999). STATUS. American Wigeon numbers vary widely between droughts and wetter periods (Mowbray 1999), but data from the North American Breeding Bird Survey for 1980-2007 suggest little population change for this period (Sauer et al. 2008)' The abundance of wigeon in Texas as a winter resident indicates their future in this state is favorable. Text by Robert C. Tweit (2008) |
