Article Abstract:
The spectacled eider duck has been listed under the Endangered Species Act because of a decline in its population over recent years. A crucial aspect of the ducks' decline is the survival of juveniles. A study conducted on the Yukon-Kuskokwim Delta, AK, has used radiotelemetry to track mortality rates among adult female ducks and their young. The findings show that duckling survival rates were similar to those for dabbling ducks and higher than those for common eiders. However, survival rates for brood-rearing adult females were low, with predation and lead poisoning being the main causes of death, and this could be an important factor in the population decline.
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Article Abstract:
Poisoning from spent lead shot has been identified as one of the potential causes of spectacled eider mortality in the Yukon-Kuskokwim (Y-K) Delta, Alaska. A new study investigates the effect of spent lead shot on the survival rates of adult female spectacled eider in two sites on the Y-K Delta. It is shown that adult females exposed to lead shot before egg hatching have a lower survival rate than unexposed females and that lead poisoning may prevent the recovery of local populations.
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Article Abstract:
A model was developed to estimate the survival rate of young waterfowl and the associated standard error for brood mixing in random samples of male and female adult birds. The model was patterned after the general modeling frameworks of the Kaplan-Meier procedure and modified Mayfield procedure. It assumes that individuals within the population have varying and independent survival probabilities. The results of the tests conducted are presented.
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