engleski

Spacing behaviour of middle spotted (Dendrocopos medius) and great spotted woodpecker (Dendrocopos major) in an urban forest

Although urbanization generally decreases biodiversity of an area, some urban areas may provide beneficial conditions for existence of some species. Urban forests may provide better habitat conditions for woodpeckers than surrounding non-urban but managed forests if specific habitat and area requirements are satisfied. Very dense populations of middle spotted Dendrocopos medius (29 p/km2) and great spotted woodpecker Dendrocopos major (43 p/km2) exist in the Maksimir park of Zagreb (Croatia). Total area of park is 3 km2 with 1.5 km2 of compact old sessile oak-hornbeam forest which is in some parts older than 300 years. In order to test hypothesis that in such dense populations home ranges should be small, we radio-tracked 11 adult great spotted and 7 adult middle spotted woodpeckers to investigate their spacing behaviour. The field work was carried out in breeding seasons of 2007 and 2008, from the second half of May to the end of June. Home-range sizes (95% MCP) in great spotted woodpecker averaged 2.4 ha (n=5, SE=0.89) and in middle spotted 4.9 ha (n=4, SE=1.34). Core areas (50% MCP) averaged 0.256 (SE=0.08) and 1.2 ha (SE=0.41) respectively. Average home range of middle spotted woodpecker was twice as big as the home range of great spotted, while core areas were even five times bigger. Unlike middle spotted, great spotted woodpecker used gardens and orchards in the park's neighbourhood as supplemental feeding grounds. Birds that breed closer to the edge of the park were more apt to take ventures to gardens than those that breed in the park's centre.

Dendrocopos major ; Dendrocopos medius ; home range ; radio-tracking

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