Diet and Nutrition of Breeding Female Redhead and Canvasback Ducks in Nevada

Diet, nutrition, and foraging strategies of breeding female canvasback (Aythya valisineria) and redhead ducks (A. americana) were studied by collecting foraging birds in 1980 and 1981 at Ruby Lake National Wildlife Refuge (Ruby Lake NWR). Female canvasbacks consumed a small number of food items, most of which were not abundant in the marsh. The diet of redheads changed with each stage of the reproductive cycle; they usually foraged on the most abundant foods in the marsh. Nutrient and energy content of the diet of canvasbacks varied little from laying through brooding, but both were quite variable in the diet of female redheads. Female canvasbacks retained large lipid reserves during formation of the clutch but used 68% from late laying to the incubation stage. Redheads expended 46% of their lipid reserves during formation of the clutch and 30% from late laying to incubation.