Extra-pair paternity and intraspecific brood parasitism in the European starling, Sturnus vulgaris: evidence from DNA fingerprinting

Abstract

Abstract. The frequency of extra-pair paternity and intraspecific brood parasitism was determined, using multilocus DNA fingerprinting, in a single population of the European starling during two subsequent breeding seasons. The results were compared with behavioural data about the rates of extra-pair copulation and intraspecific brood parasitism. Fourteen families including 62 chicks were analysed. Behavioural observations suggested a low level of intraspecific brood parasitism and indeed only one case was detected by DNA fingerprinting. Extra-pair copulations were not observed, but the DNA fingerprint data revealed six offspring (9·7%) from four broods (28·6%) where the putative father of the chick was not the genetic father. One brood was fathered by three different males. Behavioural observations suggested that at least three cases of extra-pair paternity (three offspring from two broods) could have arisen through rapid mate replacement rather than through extra-pair copulations. There was no significant evidence that polygynous males suffer from a higher risk of being cuckolded than monogamous males.