Trends in Duck Breeding Populations, 1955-2007

This report summarizes information about the status of duck populations and wetland habitats during spring 2007, focusing on areas encompassed by the U.S. Fish and Wildlife (USFWS) and Canadian Wildlife Services’ (CWS) Waterfowl Breeding Population and Habitat Survey. This report does not include information from surveys conducted by State or Provincial agencies. In the traditional survey area, which includes strata 1-18, 20-50, and 75-77 (Fig. 1), the total duck population estimate (excluding scoters [Melanitta spp.], eiders [Somateria and Polysticta spp.], long-tailed ducks [Clangula hyemalis], mergansers [Mergus and Lophodytes spp.], and wood ducks [Aix sponsa]) was 41.2 ± 0.8 [SE] million birds. This was 14% greater than last year’s estimate of 36.2 ± 0.6 million birds and 24% above the 1955-2006 long-term average (Tables 1-12). Mallard (Anas platyrhynchos) abundance was 8.0 ± 0.3 million birds, which was 10% above last year’s estimate of 7.3 ± 0.2 million birds and 7% above the long-term average (Appendix A). Blue-winged teal (A. discors) abundance was 6.7 ± 0.4 million birds. This value was the third highest estimate since 1955, 14% greater than last year’s estimate of 5.9 ± 0.3 million birds, and 48% above the long-term average. Estimated abundances of gadwall (A. strepera; 3.4 ± 0.2 million) and Northern shovelers (A. clypeata; 4.6 ± 0.2 million) were also above those of last year (+19% and +24%, respectively) and well above their long-term averages (+96% and +106%, respectively). Estimated abundance of American wigeon (A. americana; 2.8 ± 0.2 million) was 29% greater than last year but similar to the long-term average. Estimated abundances of green-winged teal (A. crecca; 2.9 ± 0.2 million), redheads (Aythya americana; 1.0 ± 0.08 million), and canvasbacks (A. valisineria; 0.9 ± 0.09 million) were similar to last year’s, but were each >50% above their long-term averages. Abundances of Northern shovelers, redheads, and canvasbacks were the highest ever estimated in this survey area, and the