Densities and dispersion of breeding Eurasian Hobbies Falco subbuteo in southeast England.

摘要

Capsule: Breeding Hobbies are more numerous in parts of southeast England than previously recognized, and in suitable habitat their breeding dispersion shows a regular pattern. Aims: To establish the density and breeding dispersion pattern of a population of Hobbies in southeast England. Methods: Surveys to locate every pair of Hobbies present were conducted in six study areas of between 48.0 and 201.2 km2 in three counties in southeast England during 2005-10. Results: Each study area held between 7 and 21 pairs. Densities were higher than in previous studies conducted in Britain, at between 9.0 and 15.0 pairs per 100 km2. Mean densities per unit area of non-developed habitat were also consistently higher than expected, at between 10.1 and 17.3 pairs per 100 km2. The mean nearest known neighbour distances fell within the range 1.8-2.8 km. In all six study areas, pairs were regularly spaced. The majority (68.0%) of nesting and territorial pairs occupied sites in woodland. Conclusions: Breeding Hobbies are considerably more numerous in parts of southeast England than previously recognized, and numbers appear to be continuing to increase. Accurate population estimates for Hobbies require species-specific fieldwork.Digital Object Identifier http://dx.doi.org/10.1080/00063657.2011.644261