Density and foraging habitat selection of waterbirds breeding in the San Luis Valley of Colorado

We determined density and foraging habitat selection of American avocet (Recurvirostra americana), killdeer (Charadrius vociferus), Wilson's phalarope (Phalaropus tricolor), cinnamon teal (Anas cyanoptera), gadwall (A. strepera), mallard (A. platyrhynchos), redhead (Aythya americana), and white-faced ibis (Plegadis chihi) during prenesting and nesting on a wetland complex in the San Luis Valley, Colorado from 15 April to 4 July 1995 and 1996. Selection patterns differed among species and between the prenesting and nesting periods for cinnamon teal and redheads. Most species preferred seasonally flooded basins with no emergent vegetation and wetlands with short (<40 cm) emergent vegetation compared to other available habitats. The results suggest that, for each of these species, biologically meaningful differences occur among foraging habitats at the spatial resolution we measured. Because we used water depth to control for differences in habitat availability for individual species, we speculate that differences in food abundance, vegetation structure and composition, and behavioral strategies during the breeding season collectively influence selection of foraging habitats.