Migratory movements of western European Montagu's Harrier Circus pygargus: a review

Abstract

We review the migratory movements of European Montagu's Harriers, based on 152 ringing recoveries (from data published up to 1993) and published data on counts at migratory convergence points. Data were analysed according to age groups and time of the year (pre- and post-breeding migration). Results showed two main migratory routes across the Mediterranean for the western European Montagu's Harriers (Gibraltar and the Sicily Channel). Passage frequency was higher in the post-breeding than the pre-breeding migration in the Gibraltar Strait, but the opposite occurred in the Sicily Channel. We discuss the possibility that Montagu's Harriers present a partially circular migration, maybe as a result of movements within the wintering areas. Recovery frequency varied according to age group, being lower for first-year birds than expected from random, which suggests that some first-year birds do not return to the breeding areas during their first summer.