FOOD-HABITS OF FALL MIGRANT SHOREBIRDS ON THE TEXAS HIGH-PLAINS

The feeding ecology of 9 migrant shorebird species (Calidris minutilla, C. mauri, C. himantopus, Limnodromus scolopaceus, Recurvirostra americana, C. bairdii, Tringa flavipes, Phalaropus tricolor, Charadrius vociferus) using inland freshwater habitats (playa lakes) on the Texas High Plains was studied from September 7-21, 1980. Shorebirds were collected from a representative playa lake where species-specific dietary and foraging site comparisons were determined. Migrant shorebirds seemed attracted to specific foraging sites where food was abundant. The occurrence of these sites within the overall playa lake regime was probably limited, but shorebirds appeared to use food resources efficiently. Based on diets, coefficients of dietary overlap, behavior and foraging sites selected by each species, shorebirds did not appear to be competing. An hypothesis is presented that shorebirds experience some population regulation during the migratory portion of their annual cycle.