Survival and Hunting Mortality of Pacific Black Ducks and Grey Teal

Abstract

To examine the importance of hunting mortality in the population dynamics of waterfowl in southwestern Australia, we estimated survival and recovery rates of 19,523 Pacific black ducks (Anas super-ciliosa) and 2,487 grey teal (A. gibberifrons) banded in 1968-76 and recovered by 1978. Both species showed strong evidence of year-to-year variation in survival rates, which averaged 63 +/- 4(SE)% and 56 +/- 6% for adult and young Pacific black ducks, respectively, and 55 +/-17% for adult grey teal. First-year recovery rates indicated the average annual hunting mortality over 6 years for Pacific black ducks and grey teal exposed to heavy hunting pressure was 23 +/-2% and 17 +/-2%, respectively. Hunting mortality was 9% in 1 year for Pacific black ducks exposed to light hunting. Estimates of mortality rate on opening day of hunting seasons at a site of intense hunting varied between 7 and 20% for Pacific black ducks and 5 and 16% for grey teal. In an intensively hunted waterfowl population in southwestern Australia, nearly 60% of all mortality of Pacific black ducks and 40% of grey teal mortality resulted from hunting. Hunting probably caused <25% of mortality in most parts of southwestern Australia, however, and there was no evidence of hunting reducing survival rates.