Ardea
Official journal of the Netherlands Ornithologists' Union

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van Beusekom C.F. (1972) Ecological isolation with respect to food between Sparrowhawk and Goshawk. ARDEA 60 (1-2): 72-96
Sparrowhawk and Goshawk live in almost the same habitats, and use a similar hunting technique. The Goshawk mainly takes species of larger size than does the Sparrowhawk, but there is a certain range of overlap. This relation is more closely analyzed with the use of data from literature. For this purpose the prey species have been divided into seven weight classes. By calculating the average consumption per weight class from their joint supply, it is demonstrated that Sparrowhawk and Goshawk occupy almost quite separate food niches, in spite of the overlap observed. Moreover, these niches appear to be complementary; predation by the two hawk species covers the whole range from very small to big prey animals, and is about directly proportionate to the size of the supply in each weight class.


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