Mate choice in American Redstarts: by territory quality?

Abstract

We consider the hypothesis that mate choice in American Redstarts (Setophaga ruticilla) depends primarily on features of territories held by males. We test the hypothesis that the territories of yearling males are demonstrably different from and inferior for reproduction to those of adult males. Territories held by the two age-classes in New Brunswick, Canada, were floristically different, but there were also major differences in territorial features in three microgeographic areas, both within each age-group and without regard to age. There were greater differences in nest success between areas than between the age-classes. We detected no differences in immediate nest site features between nests built by the mates of yearling and adult males. There were differences across the three areas in the species of trees used as nest sites, probably reflecting differences in availability. Support for the claim of different reproductive success in relation to quality of territories held by the two age-classes of males is not convincing.