ABSTRACT Diet composition of different populations of the same raptor species may differ according to the structure of local food supply. Moreover, some prey species may be preferred more than others following raptors' prey selection. This study aimed to describe diet composition of breeding Eurasian sparrowhawks ( Accipiter nisus ) in relation to land cover and food supply, and to test the effect of several prey species characteristics on sparrowhawks' prey selection in a Central European rural area (Czech Republic). Data on the sparrowhawks' diet were gathered in the vicinity of their nests (a total of 1107 prey items from the surroundings of 62 nests). The structure of food supply within sparrowhawks' assumed hunting areas was estimated. Sparrowhawks' diet composition was compared with the structure of land cover and with the food supply in their hunting areas. The effect of prey species characteristics on their vulnerability to sparrowhawk predation was tested. The diet consisted almost exclusively of birds, and the diet composition was affected by the structure of land cover around the sparrowhawks' nests. Some prey species were more preferred than others. Intermediate body mass, lower population density, and brighter plumage colouration of prey species were associated with increased vulnerability to sparrowhawk predation. These results suggest that sparrowhawks specialize in hunting birds, but they can hunt a wide variety of available bird species. Their diet composition may be based on habitat structure in their hunting areas, and some prey species may be more preferred than others depending on their specific set of characteristics.
Dvořák et al. (Tue,) studied this question.