ABSTRACT
The booted eagle (Hieraaetus pennatus) is mainly a summer resident in Eurasia, wintering in sub-Saharan Africa. It migrates by soaring-gliding flight, alone or in small, loose, flocks. In order to reach their wintering grounds, the majority of booted eagles concentrate at bottle-necks such as the Strait of Gibraltar, the Bosphorus and Batumi. The bulk of the European population breeds in the Iberian Peninsula and spend the winter in Sahel, even if some individuals remain in Spain. Others migrate towards Italy, using a route that is showing an increasing trend in the last years, albeit with a strong annual variation. Satellite tracking of Spanish birds show that these long-distance migrants need three to four weeks to reach the wintering grounds. In contrast with the majority of other migrant species, higher travel rates (hourly speed, daily distance, overall migration speed and overall straightness) are attained during autumn rather than during spring migration.
