Variation in Band-recovery and Survival Rates of Mottled Ducks in Florida

The failure to recognize heterogeneity in band-recovery and survival rates can lead to biased estimates and spurious inferences regarding population status. We examined band-recovery data for sources of variation in recovery and survival rates of mottled ducks (Anas fuhigula) in Florida. Distances between banding and recovery sites were small (median = 38 km), suggesting that mottled ducks live much of their lives within the same drainage basin. Recovery rates varied among regions of banding, perhaps because of spatial heterogeneity in bandreporting rates. Cohort-specific survival rates also may have varied by region, but data were inadequate to test these hypotheses. Fledged and unfledged young had similar recovery distributions and rates. Young of both sexes had higher recovery rates than adults, but age-specific survival differed only among males. Differences in recovery and survival rate estimates between sexes were small (<24%), consistent with reports for other waterfowl species that have long-lasting pair bonds. Temporal variation in recovery and survival rates was not related to restriction of hunting regulations, perhaps because of low statistical power (<0.3) and unmodeled geographic variation in recovery rates.

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