Absence of strict monogamy in the Eurasian jackdaw, Coloeus monedula

The Eurasian Jackdaw is thought to be archetypically monogamous, but recent tagging research uncovered extra-pair copulations in the species. Here we examined extra-pair paternity (genetic monogamy) in Eurasian jackdaws breeding in the Judean Hills, Israel, at the global edge of the species range, using a set of highly polymorphic molecular microsatellites. We found roughly a sixth of nests sampled showed deviations from monogamy, more than previously found in DNA fingerprinting studies of jackdaws, suggesting a mixed mating strategy in this population. These findings support the trend of extra-pair paternity in avian species, even when social monogamy remains the rule, and highlight the importance of continued study of species throughout their geographical range.