Context-dependence of the relationship between extra-pair paternity and breeding synchrony in the house wren Troglodytes Aedon.

LABARBERA, K., P.E. LLAMBÍAS AND I. J. LOVETTE

Pitsburgh, USA

Congreso; The Wilson Ornithological Society and Association of Field Ornithologists’ joint meeting; 2009

Wilson Ornithological Society

Rates of extra pair paternity (EPP) vary widely among and within bird species. Several hypotheses link EPP rates to patterns of breeding synchrony, but the available data have no clear pattern linking these variables. We investigated whether the lack of a consistent association between EPP and synchrony might be due to variation in life history traits, which could alter the implications of high or low synchrony and thereby change the direction of an EPP rate synchrony relationship. We studied breeding synchrony and EPP rates for two field seasons each in one northern temperate (Ithaca, NY) and one southern temperate (Buenos Aires, Argentina) population of House Wrens. These populations differ innumerous life history traits, including whether they migrate. The northern population had significantly higher EPP rates and higher breeding synchrony, although the difference in synchrony was modest. In neither population was the proportion of extra pair young within a nest related to the nest’s synchrony index. These results suggest that the contradictory data on the EPP rate synchrony association are notcaused by differences in life history context, but instead may be due to a lack of any direct relationship between these variables.