Hunger-dependency of hiding behaviour after a predator attack in dominant and subordinate Willow Tits.

We studied rank-specificity of predation risk taking in captive Willow Tits Parus montanus. Level of risk taking was expressed by duration of hiding after a simulated predator attack. By manipulating available food, we separated the effects of hunger and other rank associated factors on accepted predation risk. As expected, hungry birds took more risks than satiated ones. When both the dominants and the subordinates were hungry or satiated, no rank-related differences existed in the duration of hiding. When the dominants had consumed more food than the subordinates, they also hid longer. Similarly, the subordinates hid longer when they were satiated and dominants hungry. We conclude that in cautiousness of subordinates, reported earlier with regard to variety of antipredatory behaviours of flocking birds, probably reflects a strategy to cope with high risk of starvation resulting from restricted access to food.

Koivula K., Rytkonen S. & Orell M, ARDEA 83 (2): 397-404