Nesting behaviour of short-toed eagles (Circaetus gallicus) in central Italy, as revealed by nest cameras

Abstract

During 2021, from 1 March to 31 August, we used camera-traps to monitor two short-toed eagle pairs in the Tolfa hills (Latium, central Italy) with the intention of observing differences in behaviour between the two sexes and between different pairs during the entire breeding cycle. Males carried mainly dry twigs during the pre-laying period; females carried mostly leafy twigs usually after laying. Brooding is carried out almost entirely by the females (83 vs 17%), and females alone were observed to brood during the night. The adults’ behaviour differed even further during the fledging period: the male went hunting and limited himself almost exclusively to delivering the prey, while the female continued to remain at the nest until the chick was 22 days old, after which her absences increased constantly up to the 45th day, which is more than half of the fledging period. Female-chick interactions can be frequent and lasts up to the middle of the fledging period. Significant behavioural differences emerged from the comparison between the two pairs during the pre-laying period: in particular the average daily presence at the nest (72 vs 31 min) and the number of prey items offered at the nest by the male (29 vs 4). We also observed evident differences between pairs in the nest courtship displays. In one nest we observed an unmistakable and frequent behaviour, that we propose to call “neck display”, and which was never observed in the other nest.