TITLE

Breeding synchrony and extra-pair mating in red-winged blackbirds

AUTHOR(S)
Weatherhead, P. J.
PUB. DATE
March 1997
SOURCE
Behavioral Ecology & Sociobiology;Mar1997, Vol. 40 Issue 3, p151
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
Using data from a 6-year paternity study of red-winged blackbirds, Itested the hypotheses that increased nesting synchrony should eitherpromote extra-pair mating by increasing the advantage of extra-pairmating to females, or decrease extra-pair mating by constraining malesfrom seeking extra-pair copulations. Contrary to these hypotheses, the occurrence of extra-pair paternity did not vary with nesting synchrony over the breeding season, or vary with the number of synchronousnests within territories or within marshes, or with nesting order onterritories. However, for nearly all nests with extra-pair young, there were fewer females synchronous with that nest on the cuckolder's territory than on the territory of the cuckolded male. This 'advantage' of a synchrony difference was less pronounced for older males thatcuckolded younger males, particularly when the two males were not neighbors. Collectively, these results suggest that breeding synchrony affects extra-pair mating by affecting mate guarding, but that breeding synchrony alone can not be used to predict which females are more likely to engage in extra-pair mating, nor with which extra-pair males they will mate. Understanding why extra-pair mating by older males is less affected by breeding synchrony may explain much about both the proximate and ultimate causes of extra-pair mating in red-winged blackbirds.
ACCESSION #
8393156

 

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