Reevaluating the Cost of Natal Dispersal: Post-Fledging Survival of Red-bellied Woodpeckers

Abstract

Accurate estimates of juvenile survival are critical to understanding population processes. However, information about post-fledging vital rates is lacking for most avian species because of the difficulty of following individuals after they leave the nest. We radio-tagged 43 Red-bellied Woodpeckers (Melanerpes carolinus) as nestlings. We tracked the birds for 5 months after fledging, during exploratory forays and after natal dispersal. We modeled the influence of intrinsic, temporal, social, and landscape factors with the potential to affect survival during the post-fledging period. Estimates of post-fledging survival were best explained by fledgling age. Predictions of weekly survival rates were 0.94 for birds 1 week after fledging, then quickly increased to over 0.99 for birds 7–22 weeks after fledging. We calculated period survival for the entire 5 months as 0.80 (95% CI: 0.65–0.90). We observed no mortalities after the birds departed natal territories, suggesting that exploratory and dispersal behaviors are not costly in this species.