The importance of genetic evidence for identifying intra‐specific brood parasitism

Intra‐specific brood parasitism is widespread among birds. When genetic evidence is not available, criteria like super‐normal clutch size, high within‐clutch variance in egg morphology, and shorter than normal laying intervals have been used to identify parasitized broods. Here we report genetically determined parentage of a clutch of super‐normal size in a species with fixed clutch size, the northern lapwing Vanellus vanellus . Results from multi‐locus DNA fingerprinting revealed no loss of parentage in this brood. Furthermore, no loss of parentage was found in another clutch with a high variance in egg size and colouration. These findings add to previous evidence that reliable classification of brood parasitism requires molecular analysis.