Survival and Recovery Rate of Canada Geese Staging in Interior Alaska

Abstract

Abstract: Lesser Canada geese (Branta canadensis parvipes) are indistinguishable from other subspecies of small Canada geese on the wintering grounds using current survey methods. Consequently, managers are unable to adequately measure their abundance. Without direct estimates of abundance, researchers often use estimates of vital rates that influence abundance (e.g., annual survival) to monitor potential impact of harvest on the population. Based on capture and re‐sighting data records of 567 geese marked from 1994 through 1998, we calculated annual survival and recovery rates for different age and sex classes of white‐cheeked geese staging in interior Alaska. We compared those survival and recovery rates with those of other neck‐collared white‐cheeked geese. The best approximating model allowed survival to vary by age class while holding Seber's recovery probability (r̂) constant over sex, age class, and time. We estimated annual survival to be 0.49 (SE = 0.05) for hatch‐year geese and 0.68 (SE = 0.03) for after‐hatch‐year geese based on the weighted average of all models with a change in Akaike's Information Criterion adjusted for small sample size and lack of fit < 4. Estimates of annual survival of white‐cheeked geese in this study are among the lowest and recovery estimates are among the highest for migratory populations of neck‐collared geese. Low survival estimates of Canada geese in our study suggest that harvest rates may be higher than in many other populations. Surveys to estimate abundance or other population parameters such as reproductive success and recruitment are necessary to determine whether this population is self‐sustaining. Furthermore, we recommend monitoring abundance and harvest of small white‐cheeked geese east and west of the Cascade Mountain Range separately to better determine harvest pressure on white‐cheeked geese wintering east of the Cascades.