EXTRA-PAIR COPULATIONS AND PATERNITY IN SHAGS - DO FEMALES CHOOSE BETTER MALES

DNA fingerprinting of a colony of shags (Phalacrocorax aristotelis) revealed that the frequency of extra-pair paternity (EPP) is correlated with the level of reproductive success in the colony, and that pairs that have smaller broods at fledging are more likely to have an EPP chick. Observation of all the courtship and mating activities for two of the years showed that the females that failed to fledge chicks in years of poor breeding success were the females that had most of the extra-pair copulations (EPCS). Males that bred successfully in these two years were more successful in attracting females to their territories for Epcs. These findings are consistent with the hypothesis that females SoliCit EPCS to enhance the genetic quality of their offspring.