Observations on the roosting behaviour of adult male Golden Eagles from satellite telemetry

Abstract

ABSTRACT The roosting behaviour of two adult male Golden Eagles Aquila chrysaetos was studied using GPS satellite tags. One eagle (tag 816) used 120 different roost sites over two years and the other (tag 991) more than 87 roosts over one year. These numbers of roost sites were substantially greater than expected from previous field-based studies. Around 70% of the roost sites were used on only one night and such roosts accounted for 17–25% of roosting behaviour. Seven roosts that were used for more than ten nights each (multi-use roosts) were located for one bird and five for the other. Roosts that were used on only one night tended to be used more than expected on evenings when winds were light (<5 ms-1), while multi-use roosts were used more than expected on evenings with strong winds (>10 ms-1). Hence, eagles appear to select more-sheltered, multi-use roost sites during strong winds.