Breeding Waterfowl Populations in South Dakota

Abstract

Breeding waterfowl in South Dakota were censused on 500 legal quarter sections within 125 clusters representing a proportional stratified random sample of 0.16 percent of the state area. Two breeding pair counts, one in May and second in June, were conducted each year on the sample units in 1973 and 1974. Densities of total breeding pairs averaged 5.58 and 2.30 pairs per km2 in 1973 and 1974, respectively. Estimated populations based upon these densities were 1,067,500 breeding pairs in 1973 and 439,600 breeding pairs in 1974. The 58.8 percent decrease in the population occurred concurrently with intensification of drought conditions throughout South Dakota in 1974. Blue-winged teal (Anas discors), mallard (Anas platyrhynchos), pintail (Anas acuta), and gadwall (Anas strepera) were, in that order, the most abundant species. Diving ducks constituted less than 5 percent of the population each year. Highest diving duck densities were restricted to the northern periphery of the Coteau des Prairies. Most of the remaining diving duck pairs occurred in the central Coteau des Prairies and in the Coteau du Missouri. Highest dabbling duck densities were found in the northern Coteau des Prairies and in the major portion of the Coteau du Missouri. Median densities occurred in the Minnesota River-Red River Lowland and the major portion of the James River Lowland. Low densities were found in the remainder of the state. Population estimates from this method compared favorably with those obtained by aerial transect methods used by the U.S.Fish and Wildlife Service