Potential Reproductive Consequences of Winter-Diet Restriction in Mallards

Food restriction during winter may subsequently affect waterfowl reproduction. Therefore, we tested the effects of restricted and ad libitum (control) food availability during winter 1987-88 on reproductive performance of captive wild-strain and game-farm female mallards (Anas platyrhynchos) in Mississippi. Females fed restricted diets weighed less (P 0.05) between females fed restricted diets and those fed ad libitum. Few wild-strain females renested, but clutch sizes of game-farm females declined (P < 0.01) after initial nests. Simulation modeling revealed that recruitment rates (i.e., n F/breeding F) may decrease 3-15% if free-ranging mallards were to experience nesting delays of 1-3 weeks. We hypothesize that poor feeding conditions during winter could negatively affect mallard recruitment primarily through delayed nesting, but replication of our study with wild-strain ducks and other experimental design considerations is recommended. J. WILDL. MANAGE. 58(4):780-786