Differential migration in the polygynandrous Alpine Accentor Prunella collaris

Abstract

Capsule Differential migration by sex and age occurs in the Alpine Accentor Prunella collaris. Aims To characterize the wintering phenology of migrating Alpine Accentors, and to test for differences in sex and age ratios between wintering sites. Methods Alpine Accentors wintering at low elevation, in Mediterranean France, were monitored (census, ringing) over four winters. Individual arrival date, duration of stay and departure dates were analysed according to sex and age. Within‐day use of the site was characterized. Results were combined with previously published data to test for differential migration. Results Post‐breeding migration was recorded in November. Yearlings arrived 22 days later than adults at the wintering site. Females stayed longer (108 days) than males (77 days). The study site – a picnic place – was mainly used by the birds in the afternoon. Males departed earlier (22 February) than females (7 March). The inter‐annual return rate was 0.61 (without transients). Conclusion Combining these results with available estimates of age and sex ratios from other wintering populations revealed that female and yearling Alpine Accentors are more prone to migrate than adult males. Differential migration probably results from the ecological selective pressures faced by the species, particularly their high‐altitude breeding grounds and their polygynandrous mating system.