Abstract:

Red-footed Falcons are gregarious trans-equatorial migrants, forming up to several thousand strong roost sites after the breeding season and before commencing migration. This pre-migration period is presumed to play a major role in defining the survival of long-range migrants. Here we investigate the autumn movements of 8 individu­als caught and satellite-tagged within the Carpathian Basin. We found that birds may use multiple roost sites that can be separated by large distances. A single individual’s home range was 88 km² (80% kernel home range) and was near concentrical to the roost site. Two individuals travelled to southern Ukraine soon after tag-deployment. Our results demonstrate that even a small number of satellite tagged birds show behavioural plasticity in terms of roost site selection indicating that post-breeding foraging habitat choice decisions may have substantial variability. The night localization points of birds marked out 2 and 5 yet unknown potential roost sites in Hungary and in the Ukraine, res­pectively. Using the data of an international weekly survey (2006–2011) carried out in the Carpathian Basin, we cross-referenced the departure dates of tagged individuals with the 6 year means of counted individuals. The tagged birds initiated migration with the first 25% percent of the surveyed population.