Breeding dispersal of Eurasian Hoopoes (Upupa epops) within and between years in relation to reproductive success, sex, and age

摘要

Breeding dispersal is often affected by previous reproductive success, age, and sex. Birds with multiple broods within a season can disperse not only between, but also within, years. Little is known about factors that govern dispersal within a season or how strong it is compared with dispersal between years. We studied breeding dispersal of Eurasian Hoopoes (Upupa epops) in Valais, Switzerland, using capture-recapture data collected over 8 years (n = 712 individuals). We analyzed breeding dispersal probability and distance, both between and within years, in relation to age, sex, and reproductive output, using multistate capture-recapture models and generalized linear models. Between years, females dispersed more often and over longer distances than males (mean distance, females = 1.98 km; males = 0.83 km), but dispersal was only weakly affected by age and previous reproductive success. Dispersal within a year also differed between sexes (mean distance, females = 1.45 km; males = 0.46 km) and varied little with age or previous reproductive success. Dispersal probability within years was lower and occurred over shorter distances than dispersal between years. Thus, dispersal decisions did not seem to depend on different cues, although dispersal within the breeding season might be constrained by habitat saturation. Breeding dispersal was common in Hoopoes, compared with other bird species. Together with the fact that immigration is an important component of this species' population dynamics, such dispersal patterns suggest that successful conservation of Eurasian Hoopoes requires extended breeding grounds to maintain sustainable populations.