The importance of landscape structure for nest defence in the Eurasian Treecreeper Certhia familiaris

Abstrakti

Forest loss and fragmentation induces harmful ecological effects especially for species preferring mature forests. The Eurasian Treecreeper, Certhia familiaris, is highly special-ised in foraging on large tree trunks and can only occasionally forage outside of mature fo-rests. We quantified nest defence behaviour of Treecreeper parents toward a stuffed model of Great Spotted Woodpecker Dendrocopos major in central Finland. We used a Geographical Information System (GIS) to measure the landscape structure within a 200 m radius around the nest. We found that females with more fledged offspring gave alarm calls from farther away from the predator model than did females with fewer fledged off-spring. The alarming distance of females was longer when the forest patch around the nest was larger. In males, however, alarming distance decreased with increasing home patch size. It seems that forest loss may influence parental nest defence behaviour, which is one of the fundamental life-history traits in birds. The association between habitat characteris-tics and nest defence behaviour of birds need more attention to understand how human modified habitats affect bird breeding success.