Forest size and isolation have no effect on reproductive success of Eurasian Nuthatches (Sitta europaea)

Abstract

We collected data on breeding success, nestling mass, fledging date, and recruitment of Eurasian Nuthatch (Sitta europaea) nesting attempts in a number of small (<30 ha) forest fragments and parks, as well as in two larger (>200 ha) forests. Most study areas were dominated by well-developed oak stands. We found no differences in reproductive parameters between fragments and the two large forests, nor any relationship with the size or degree of isolation of individual fragments. Failed nests more often were taken over by nest competitors (particularly starlings) in fragments, but this did not seem to affect overall success rates. Pairs nesting in parks had a lower chance to produce recruits than pairs in similar-sized oak fragments, and early broods recruited more offspring than late broods. We conclude that fragmentation does not affect the suitability of mature oak stands for reproduction of nuthatches within the size range of oak stands frequented by this species.