Kunnen Boomvalken Falco subbuteo nestpredatie voorkomen?

A single nest of Hobbies was observed in the nestling stage during 21 visits in 1997. It was an old crow’s nest, at a height of 12 m in a poplar in open farmland in the province of Groningen. It contained three young, which fledged between 15 and 18 August. During the survey, nine other raptors were recorded in the vicinity of the Hobby nest: 2x Goshawk Accipiter gentilis, 1x Sparrowhawk A. nisus, 2x Common Buzzard Buteo buteo and 3x Kestrel Falco tinnunculus. All raptors within a 200 m radius around the nest were chased and/or attacked. A juvenile female Goshawk elicited a fierce response (steep diving, calling), and despite taking cover in trees, she was forced to leave the immediate surroundings of the Hobby nest. It is suggested that Hobbies in The Netherlands have a better chance of rearing young in open farmland than in woodland. The latter used to be the core breeding habitat, but Hobbies declined by at least 50% during the last decade (Bijlsma & de Vries 1996), especially in woodland habitats and probably because of Goshawk predation. Nest defense against Goshawks is presumably more effective in open habitats than in woodland.