Movement patterns of Sooty Falcons Falco concolor tracked via satellite across their annual cycle

Abstract

ABSTRACT Capsule Sooty Falcon Falco concolor movement patterns were strongly dependent on the phase of their annual cycle, and were clearly discernible in terms of the average hourly travel speeds of falcons during those phases. Aims To better understand the movements of Sooty Falcons on migration, during the winter and as non-breeding individuals. Methods Eleven Sooty Falcons were tracked via satellite, and their movements were analysed. Results Movement patterns were strongly dependent on the phases of the annual cycle. Falcons exhibited limited movement (i.e. shortest step-lengths and smallest areas) when on the wintering and breeding grounds. Migration to and from the wintering grounds in Madagascar was characterized by high movement rates (long step-lengths), sometimes over 50 km/h. Some Sooty Falcons stopped on the African mainland coast prior to crossing the Mozambique Channel. Movement patterns during winter were similar to those exhibited by falcons while summering, except that the movements of breeding birds were spatially more restricted. Conclusions Our results highlight the need for conservation approaches appropriate to the different phases of the annual cycle, including the importance of areas immediately around island breeding sites, summering and coastal staging areas, and the need to support prey abundance along the migration route and on wintering grounds.