Variation in territorial behaviour and breeding fates among male Chaffinches

Abstract

The territorial behaviour of male Chaffinches Fringilla coelebs was studied by radio tracking in coniferous forest in southern Finland. In total 24 males were tracked in 1988-90. The local Chaffinch population consisted of birds of different breeding status : most of the males were paired and started to breed, but some of them remained unpaired forthe whole breeding season or remained unpaired after the disappearance of their mates. Nest predation increased asynchrony in breeding. The reaction to nest predation and the behaviour after successful fledging differed among both males and females. After fledging some males fed their young, whereas others did not participate in feeding but started to sing intensively. Some females made a new attempt at nesting whereas others disappeared, leaving their mates alone. The activities of the male Chaffinches were not restricted to the singing territory: all males made extra-territorial trips in every breeding stage. These trips were made for foraging or inconspicuously to the territories of other males, apparently in search of extra-pair copulations. Because of the asynchrony in the nesting cycles of different pairs, the local population included fertile females throughout the season, which increased the opportunities to pursue a mixed reproductive strategy .