Mating system and laying date in birds

Abstract

The hypothesis that polygynous species start breeding later in the season than monogamous ones was examined using two data sets, each with both monogamous and polygynous species—the eight species of wrens which breed in the USA, and five genera (15 species) of British passerines. Comparisons were made within each of 16 states in the USA from which data were available and for each genus in Britain. The hypothesis is supported for most subsets of data, but in some cases polygynous and monogamous species start breeding at the same time (but in no case do polygynous breed earlier than monogamous species). The late breeding of the polygynous species is probably an outcome of the fact that polygynous males tend to participate less in nest activities than monogamous ones.