Braakballen van Sperwers Accipiter nisus als schatkamer
De Takkeling , Volume 10 - Issue 3 p. 232- 237
In the Forestry of Staphorst (935 ha), situated in the eastern Netherlands amidst extensive farmland, large numbers of nestboxes sustain high densities of cavity- nesting passerines, particularly tits and pied flycatchers. Including nestbox-breeding pairs in the vicinity of the forestry, 10,076 nestling tits and pied flycatchers were banded in 2001 (Table 1). Seven pairs of Sparrowhawks were located in the forestry in 2001, of which 5 pairs raised 3-5 fledglings each. During visits in the nestling stage, pellets were collected on plucking sites near the Sparrowhawks eyries. These pellets revealed a total of 118 rings of four tit species and pied flycatcher Ficedula hypoleuca. Blue tits Parus caeruleus, great tits P. major, pied flycatchers and coal tits P. ater were depredated in order of abundance (Table 1), i.e. Sparrowhawks did not show a preference for any of these species. The age-distribution of captured ringed passerines showed a clear preponderance of juveniles in the Sparrowhawk diet, i.e. hunting Sparrowhawks significantly selected juveniles as prey during their chick-rearing period (Table 2). The spatial distribution of captured passerines, as depicted by their natal sites, revealed clear hunting ranges for each Sparrowhawk pair but with considerable overlap between pairs (Fig. 1).
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