US Fish & Wildlife Service
Date of this Version
7-20-2001
Citation
U.S. Fish and Wildlife Service. 2001. Waterfowl population status, 2001. U.S. Department of the Interior, Washington, D.C. 50 pp.
Abstract
In the traditional survey area (strata 1-18, 20-50, and 75-77), total duck abundance was 36.1 ± 0.6 [SE] million birds. This was 14% below (P< 0.001) last year’s estimate of 41.8 ± 0.7 million birds, but still 9% above the long-term (1955-2000) average (P < 0.001). Mallard (Anas platyrhynchos) abundance was 7.9 ± 0.2 million, which is 17% below (P<0.001) the 2000 estimate of 9.5 ± 0.3 million and similar to the long-term average (P=0.08). Blue-winged teal (Anas discors) abundance was 5.8 ± 0.3 million, which was 23% below last year’s estimate of 7.4 ± 0.4 million (P=0.001), but 29% above the long-term average (P = 0.001). Green-winged teal (Anas crecca) abundance was 2.5 ± 0.2 million, 39% above the long-term average (P<0.001) but 21% lower than last year (P=0.007). Gadwall (Anas strepera; 2.7 ± 0.1 million, +66%) and northern shovelers (Anas clypeata; 3.3 ± 0.2 million, +60%), were above their long-term averages (P < 0.04), while northern pintails (Anas acuta; 3.3 ± 0.3 million, -23%) and scaup (Aythya marila and A. affinis combined; 3.7 ± 0.2 million, -31%) remained below their long-term averages (P<0.01). Redheads (Aythya americana; 0.7 + 0.07 million) were 23% below 2000 numbers (P=0.04), and similar to their long-term average (P=0.22). American wigeon (Anas Americana; 2.5 + 0.1 million) and canvasback (Aythya valisineria; 0.6 + 0.05 million) estimates were similar to those of last year (P≥0.19) and to long-term averages (P≥0.22). Habitat conditions in May in the traditional survey area were generally wetter than last year, but varied considerably among areas. The estimate of May ponds in Prairie Canada and the U.S. combined was 4.6 ± 0.1 million, up 18% from 2000, but not statistically different from the long-term average (P=0.07). The eastern survey area comprises strata 51-56 and 62-69. The 2001 total duck population estimate for the eastern survey area was 3.3 ± 0.3 million birds, similar to last year’s total duck estimate of 3.2 ± 0.3 million birds. Abundances of individual species were similar to last year, with the exception of ring-necked ducks (Aythya collaris; 0.35 + 0.04 million, -43%, P=0.001) and buffleheads (Bucephala albeola; 0.10 ± 0.02 million, +93%, P = 0.05). The mid-continent mallard fall flight is predicted to be 10.5 million mallards, 6% lower than that of last year (P=0.02).