Perch selection by singing chaffinches: A better view of surroundings and the risk of predation

Abstract

Predation risk varies among perches, and the vulnerability of singing chaffinches (Fringilla coelebs) might differ depending on where they perch in a tree. To find out how singing of the chaffinch is associated with antipredatory behavior, I studied perch selection in mature pine forest and in pine saplings, two habitats differing in the amount of cover for protection from predators. My results show that male chaffinches prefer to sing below the canopy of mature pines and in the uppermost parts of sapling pines. Although these are the canopy parts most exposed to sparrowhawk (Accipiter nisus) attacks, staying in open sites may be a beneficial strategy for singing chaffinches because it makes it possible to improve antipredatory vigilance. This assumption was supported by the hawk experiments. After being exposed to the sparrowhawk model, all of the singing birds selected the conspicuous perch below the canopy of mature pines. The males that perched higher in the canopy before the experiment moved to the lower canopy, whereas those males that sang below the canopy did not change their singing perch.