DO RESTRICTIVE HARVEST REGULATIONS RESULT IN HIGHER SURVIVAL RATES IN MALLARDS - A COMMENT

Smith and Reynolds (1992) analyzed recovery and survival rates for mallards (Anas platyrhynchos) during periods of liberal (1979-84) and restrictive (1985-88) harvest regulations to examine the relationships between harvest and survival. Using a model explicitly relating survival to recovery rates, Smith and Reynolds (1992) concluded that restrictive harvest resulted in higher survival rates for mallards. We reanalyzed these data to examine relationships between survival rates and both harvest and population size. Mallard population size declined (P = 0.038) over the interval in question. Therefore, the apparent relationship between harvest and survival found by Smith and Reynolds (1992) is potentially spurious because kill rates and population size declined from 1979 to 1988. In our analyses, the hunting-mortality model failed to provide an explanation of variation in annual survival rates of mallards substantially superior to models of density dependence or constancy in survival rates. We conclude that there is little evidence that restrictive harvest regulations improved mallard survival, and we renew the call for experimental harvest regulations necessary to address the relationship between these 2 variables.