Apparent survival, natal philopatry, and recruitment of Barrow’s goldeneyes (Bucephala islandica) in the Cariboo–Chilcotin region of British Columbia, Canada

Abstract

We used capture–resight data to evaluate apparent survival, natal philopatry, and recruitment of Barrow’s goldeneyes ( Bucephala islandica (Gmelin, 1789)) in British Columbia, Canada. Median ages of first pairing and first breeding for females were 2 years and 3 years, respectively. The Cormack–Jolly–Seber model that best fit our data indicated that apparent survival rates (Φ) differed according to sex, year, and age class at marking. Estimates were similar for after-hatch-year (AHY) females (0.62) and AHY males (0.58), which was consistent with predictions. However, contrary to predictions, apparent survival rates of hatch-year (HY) females (0.68) were similar to those of AHY females and significantly higher than those of HY males (0.35). We interpret this difference as being primarily related to higher dispersal probabilities by HY males. Also evident was a negative correlation between apparent survival rate during the 1st year after capture for HY birds and their subsequent apparent survival rates, which suggests that probability of dispersal increased after these birds reached reproductive maturity and began to compete for breeding territories. We interpret this as evidence for density-dependent control of access to limited resources such as nest cavities.