EXTRA-PAIR PATERNITY IN THE COMMON MURRE1

Abstract

Multi-locus DNA fingerprinting was used to estimate the frequency of extra-pair paternity in the Common Murre (Uria aalge), a colonial, sexually monomorphic seabird that breeds at very high densities and in which extra-pair copulation is frequent. Common Murres produce a single chick. We detected 6 cases of extra-pair paternity in 77 families (7.8%). This value was higher than the proportion of successful extra-pair copulations (1.6%) estimated from behavioral data from an earlier study of the same population.