Parentage analyses in the pied flycatcher Ficedula hypoleuca at the western boundary of its central European range.

The study deals with the occurence of extra-pair copulations within a Pied Flycatcher population near Lingen/Emsland (52.27 degrees N, 7.15 degrees E) in northern Germany. As a whole, 31 Pied Flycatcher broods were investigated using oligonucleotide DNA fingerprinting. In 4 broods (12.9 %) a sum of 9 nestlings were found to be due to extrapair copulations of the females. Their proportion with regard to the total number of nestlings investigated (n = 165) amounts to 5.5 %. Integrating the pairing status of males into the analyses a significant difference was found: Only one of 20 obviously monogamous males was cuckolded, while for 3 of 7 bigyneous males' nestlings were identified that resulted from extra-pair copulations of the females. The proportion of cuckolded bigyneous males may be even underestimated, because in three cases the primary broods could not be investigated.