Trends in Duck Breeding Populations, 1955-2000

This report summarizes preliminary information about the status of duck populations and their habitats during spring 2000, focuses on areas encompassed by the Breeding Waterfowl and Habitat Survey. These numbers are preliminary, and do not include survey information from state or provincial surveys. The traditional survey area includes strata 1-18, 20-50, and 75-77. In the traditional survey area, total duck abundance was 41.8 ± 0.7 million birds, excluding scoters [Melanitta spp.], eiders [Somateria and Polysticta spp.], oldsquaws [Clangula hyemalis], mergansers [Mergus and Lophodytes spp.], and wood ducks [Aix sponsa]). This was similar (P=0.12) to last year’s) record estimate of 43.4 ± 0.7 million birds, and is still 27% above the 1955-99 average (P\u3c0.01). Mallard (Anas platyrhynchos) abundance was 9.5 ± 0.3 million, which is 12% below last year’s record 10.8 ± 0.3 million (P\u3c0.01) estimate but still 27% above the 1955-99 average (P\u3c0.01). Blue-winged teal (Anas discors) abundance was a record-high 7.4 ± 0.4 million. This was similar to last year’s estimate of 7.1 ± 0.4 million (P=0.61), and 69% above the 1955-99 average (P\u3c0.01). Gadwall (Anas strepera; 3.2 ± 0.2 million, +100%), green-winged teal (Anas crecca; 3.2 ± 0.2 million, +80%), northern shovelers (Anas clypeata; 3.5 ± 0.2 million, +73%), and redheads (Aythya americana; 0.9 ± 0.1 million, +50%) were all above their long-term averages (P\u3c0.01), while northern pintails (Anas acuta; 2.9± 0.2 million, -33%) and scaup (Aythya marila and A. affinis combined; 4.0 ± 0.2 million, -25%) were again below their long-term averages (P\u3c0.01). Green-winged teal was the only duck species that increased over 1999 estimates (+21%; P=0.03). American wigeon (Anas americana) and canvasback (Aythya valisineria) estimates were similar to those last year (P\u3e0.42) and to long-term averages (P\u3e0.07)