Attack success in Bonelli’s Eagle Aquila fasciata

Abstract

This paper presents the first study of foraging behaviour and hunting success in Bonelli's Eagle. Attack success was modelled as a function of biological and environmental vari-ables using observations made during a long-term monitoring. The overall attack success was 28.2%, based on 110 attack observations recorded between 1985 and 2008 in south-eastern Spain. Group size of prey was the most explicative independent variable, indicat-ing that the probability of attack success declined with increasing prey group size. Sur-prise was the main and most successful attack mode, mainly on preys foraging on the ground. The probability of success in surprise and non-surprise attacks probably declined with prey group size due to the effects of vigilance and confusion, respectively. The best model for attack success also suggested that attacks were more likely to be successful when directed at prey in areas with low bush canopy cover. This finding highlights the im-portance of open habitat types which provide foraging opportunities for the Bonelli's Eagle. Management measures for increasing open habitats in territories may create a habi-tat structure more favourable for prey detection by Bonelli's Eagles.