EXTRA-PAIR PATERNITY IN THE EUROPEAN STARLING - THE EFFECT OF POLYGYNY

We determined the frequency of extra-pair paternity and intraspecific brood parasitism in European Starlings (Sturnus vulgaris) by performin g multilocus DNA fingerprinting on 22 complete families from a populat ion in southern Sweden. Among 92 nestlings, we did not detect any succ essful intraspecific brood parasitism. This confirms observational dat a that successful intraspecific brood parasitism is rare in this popul ation. We detected eight extra-pair young. Except for one case, where all (two) nestlings were fathered by another male than the one attendi ng the nest, no more than one nestling in each nest was fathered by an extra-pair male. Although the degree of extra-pair paternity was high er in nests of secondary females than in those of primary and monogamo us females, this difference was not significant. There was no relation ship between a male's paternity with his primary and secondary female during the same reason. There was a tendency for males to loose patern ity in the broods of secondary females when the fertile periods of his females overlapped considerably. We suggest that the relative ease by which female Starlings can be mate-guarded, the fact that mate-attrac tion and mate-guarding do not have to be exclusive activities and the high within pair copulation frequency in Starlings may keep the degree of extra-pair paternity low.