Changes in physical condition of male mallards (Anas platyrhynchos) during moult

Abstract

The relationship between moult and physical condition was studied in adult male mallards (Anas platyrhynchos) collected between May and October on the Canadian Prairies in 1976. Body weight did not change significantly while birds were moulting. During the flightless period, however, there was a significant decrease in flight muscle weight, whereas leg muscle weight increased. Subcutaneous lipid depots, smallest in breeding birds, increased significantly during the prebasic body moult and decreased temporarily during the flightless period. Carcass lipid depots and total protein remained relatively constant throughout the moult. These data suggest that moulting male mallards did not encounter nutritional stress in south central Canada in 1976.