Trends in Duck Breeding Populations, 1955-2008

This report summarizes information about the status of duck populations and wetland habitats during spring 2008, focusing on areas encompassed by the U.S. Fish and Wildlife (USFWS) and Canadian Wildlife Services\u27 (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 (Figure 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 37.3 ± 0.6 [SE] million birds. This estimate represents a 9% decline over last year\u27s estimate of 41.2 ± 0.7 million birds, but remains 11% above the 1955-2007 long-term averagea (Table 1). Estimated mallard (Anas platyrhynchos) abundance was 7.7 ± 0.3 million birds, which was similar to last year\u27s estimate of 8.3 ± 0.3 million birds and the long-term average (Table 2). Blue-winged teal (A. discors) abundance was 6.6 ± 0.3 million birds. This value is similar to last year\u27s estimate of 6.7 ± 0.4 million birds and 45% above the long-term average. Estimated abundances of gadwall (A. strepera; 2.7 ± 0.2 million) and Northern shovelers (A. clypeata; 3.5 ± 0.2 million) were below 2007 estimates (-19% and -23%, respectively) but remain well above their long-term averages (+56% and +56%, respectively). Estimated abundances of green-winged teal (A. crecca; 3.0 ± 0.2 million) and redheads (Aythya americana; 1.1 ± 0.1 million) were similar to last year\u27s and were \u3e50% above their long-term averages. Estimates of canvasbacks (A. valisineria; 0.5 ± 0.05 million) were 44% below the 2007 estimate (0.9 ± 0.09 million) and 14% below the long-term average. The estimate for Northern pintails (Anas acuta) was 2.6 ± 0.1 million, which was 22% below the 2007 estimate of 3.3 ± 0.2 million, and 36% below the long-term average. The scaup estimate (Aythya affinis and A. marila combined; 3.7 ± 0.2 million) was similar to 2007, and remained 27% below the long-term average of 5.1 ± 0.2 million