Age-dependent responses to alarm calls depend on foraging activity in Willow Tits Poecile montanus

Abstract

Survivorship in animals depends on both foraging activities and avoidance of predation, and thus behavioural decisions often reflect a trade-off between predation risk and foraging efficiency. In this experimental study, we compared behavioural responses of free-living adult and juvenile Willow Tits Poecile montanus to a conspecific alarm call in two treatments. The alarm call was played back when a focal bird was either not feeding, or feeding on a sunflower seed on the middle part of a spruce branch. When feeding at the time of the alarm call, juveniles more often stayed motionless or moved shorter distances than adults. Our results suggest that in hierarchical groups, juveniles are forced to take greater risks to maintain access to food or lack experience to optimize between food and safety. © 2011 The Authors. Ibis © 2011 British Ornithologists' Union.