Trail Cameras Reveal New Details of the Breeding Behaviour of an Endangered Vulture Species

The Egyptian vulture (Neophron percnopterus) is a globally endangered species distributed in Eurasia and Africa, with a declining population in most of its range. Even though the species is well-studied, some aspects of its breeding behaviour, more precisely the share of parental care between the sexes within the pair (i.e. nest building, incubation, food provisioning), still remain poorly documented. We used trail cameras as a tool to monitor the breeding behaviour of six Egyptian vulture pairs in Bulgaria during 22 breeding attempts between 2011 and 2021. We found that the male contributes more than the female to the nest arranging (chi(2) = 4, p = 0.04), and females participate less in nest buildings than males (chi 2= 92.5, p < 0.05). The rate of copulations recorded in the nest is similar throughout the years (H = 11.95, df = 7, p = 0.1). Both sexes seem to contribute almost equally (7.14 +/- 0.126 SD hours per day on average for the female and 5.87 +/- 0.123 SD on average for the male) to the incubation across the entire period (chi(2) = 0.125, p = 0.72). Only 23% of the food delivered to the nest would be found in the remains at the end of the breeding season.