Sources of Variation in Survival and Recovery Rates of American Black Ducks

Publisher Website
Google Scholar
Abstract
Band recovery data from 10 preseason and 10 winter populations of the American black duck (Anas rubripes) were analysed and survival and recovery rates estimated. Adults showed higher survival rates and lower recovery rates than 1st-year birds. Higher harvest rates of juveniles probably explain much of the age-related mortality differential, but higher vulnerability to nonhunting mortality factors probably also plays a role. Adult males had higher survival rates than adult females but recovery rates were similar to those of adult females. Young males and females had similar survival rates, but recovery rates of young males were higher than those of young females. We suggest that most of the differential mortality of females is due to higher risk on the breeding grounds. Geographic variation was detected more frequently in recovery rates than in survival rates, and variation in both survival and recovery rates for young was more common than for adults. Recovery rates were strongly time dependent, but survival rates were not. The absence of strongly time dependent survival rates suggests that variations in hunting mortality are compensated for by other mortailty sources. Further analysis and monitoring of the American black duck population is needed to evaluate the efficacy of current management.

This publication has 2 references indexed in Scilit: