SPATIAL NICHE DYNAMICS UNDER PREDATION RISK IN THE WILLOW TIT PARUS-MONTANUS

Behavioural studies indicate that the use of foraging niches in winter ing tits is the outcome of a trade-off between using sites rich in foo d and keeping exposure to predators as low as possible. Previous studi es suggest that predation risk varies within the tree and is higher fo r 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 a ttacks using scuffed predators. After spotting an avian predator the t its shifted to forage to a larger extent in sheltered parts of the tre e than before the attack. The result shows that niche use in Willow Ti ts is directly linked to the perceived predation risk and that the bir ds assess the predation risk to be lower on the inner parts of the bra nches than further out.