Spatial niche dynamics under predation risk in the Willow Tit Parus montanus

Behavioural studies indicate that the use of foraging niches in wintering tits is the outcome of a trade-off between using sites rich in food and keeping exposure to predators as low as possible. Previous studies suggest that predation risk varies within the tree and is higher for tits using outer parts of branches and low positions in trees. This is the first study of the use of foraging sites in the tree by Willow Tits Parus montanus that actually manipulates the perceived likelihood of a predator attack. Captive Willow Tits were subject to simulated attacks using scuffed predators. After spotting an avian predator the tits shifted to forage to a larger extent in sheltered parts of the tree than before the attack. The result shows that niche use in Willow Tits is directly linked to the perceived predation risk and that the birds assess the predation risk to be lower on the inner parts of the branches than further out.