Ontmoetingen van Boomvalken Falco subbuteo met Sperwers Accipiter nisus

Several interactions between nesting Hobbies and visiting Sparrowhawks are described. The latter’s presence provoked various behavioural responses from the Hobby (all observations made during the nestling period): ‘apparently’ ignoring the Sparrowhawk, agonistic behaviour (circling silently and feinted attacks without physical contact), alarm calling whilst being stationary on the breeding site, and vigorous diving and calling. None of these responses deterred a Sparrowhawk female to use the breeding site of the Hobby to pluck its prey. One of the Hobby fledglings was found plucked near the nest, presumably by a Sparrowhawk.