The effect of forest patch size on the breeding biology of the great spotted woodpecker Dendrocopos major

Forest fragmentation leads to a decrease in total forest area and patch size, which enhances predation pressure on birds’ breeding success. Existing data suggest that because hole nesters occupy relatively safe nest sites, their breeding success is not negatively affected by this process. However, fragmentation effects on other reproductive parameters are possible and could have important influences on population growth rates. We examined the hypothesis that a decrease in forest patch size does not influence some aspects of breeding biology of a primary cavity nester-the great spotted woodpecker. We compared clutch size, the number of fledglings, breeding phenology, and nesting success between birds nesting in large forests (> 120 ha) and in small woodlots (2-55 ha). We found that almost all the parameters studied differed in relation to patch size, and were worse in small forests. Only breeding success was similar in both groups of birds.

Mazgajski, T. D. & Rejt, L. 2006, Ann. Zool. Fennici 43: 211-220