Foraging opportunism and feeding frequency in the red-footed falcon (Falco vespertinus) in Slovakia: case study from 2017

Foraging opportunism and feeding frequency are less studied parameters of behaviour in insectivorous falcons, many of which are endangered bird species. In this short study, prey composition and feeding frequency of red-footed falcon (Falco vespertinus) nestlings were studied using the method of camera recordings during seven days in July 2017 in southwestern Slovakia. Camera recording analyses of 2–3 chicks (14–26 days old) in three nests revealed a significant preference for insects (97%, n = 305 prey items), of which the Italian locust (Calliptamus italicus) was highly predominant (54%). We also found very high average chick feeding frequency (9.9 feedings per hour, n = 29 hours 22 min of regular observations), whereby the females fed their young ones more frequently (64.9%, n = 305 feedings) than the males (35.1%). Analyses of food composition in adverse weather conditions showed that unfavourable weather had a negative effect on chick feeding frequency, and in rainy weather the males fed significantly less than the females.