Nesting Giant Canada Geese in Western South Dakota

Giant Canada geese (Branta Canadensis maxima) began nesting on 27 March 1976 and 2 April 1977. Peak hatch occurred from 15 to 21 May 1976 and 22 to 28 May 1977 and the nesting season lasted 69 days in 1976 and 83 days in 1977. Average clutch size was 4.8 eggs per nest in 1976 and 5.0 in 1977. Thirty-three percent of all eggs observed in 1976 and 23% in 1977 failed to hatch. Infertility and desertion were the main reasons that eggs did not hatch. Seventy percent of the territorial pairs in 1976 and 41% in 1977 nested. Nesting success was 76% in 1976 and 79% in 1977. Mean brood size was 4.6 in 1976 and 4.7 in 1977. The estimated number of geese in the study area in 1977 was 1196 of which 573 were territorial pairs (0.5 geese per section). Approximately 3.7 goslings per breeding pair in 1976 and 3.5 goslings in 1977 survived through the flight stage. Thirty variable were analyzed using a discriminant function analysis to evaluate goose nesting habitat on stockponds. Size, headwater development, presence of an island, permanence of the pond and disturbance by livestock accounted for 52% of the variation between ponds used and ponds not used by geese. Stockponds were assigned to 1 of 4 habitat classes with Class 4 representing optimal goose nesting habitat. Size, headwater development, percent basin water, density of surrounding vegetation, distance to nearest farmstead, and southward drainage were the 6 variables which best separated the 4 classes of ponds. When “class” and the other 30 variables were entered into the analysis the presence of absence of geese on stockponds was predicted by the computer with 92% and 93% accuracy, respectively. A total of 2674 stockponds was estimated for the study area of which 1390 (52%) ponds were considered to have potential as goose nesting habitat