Search results for "Glaucidium passerinum"
showing 3 items of 3 documents
Younger bank voles are more vulnerable to avian predation
2008
The importance of predation on prey populations is mainly determined by the number of eaten prey. However, the total impact of predation might also be determined by the selection of certain prey individuals, e.g., different sexes or age categories. Here we tested selective predation by an avian predator, the pygmy owl ( Glaucidium passerinum (L., 1758)), on bank voles ( Myodes ( Clethrionomys ) glareolus (Schreber, 1780)). We compared the sex, age, and mass of hoarded prey with the animals snap-trapped from the field. There were no differences in the sex ratio between hoarded bank voles and those available in the field. However, hoarded voles were significantly younger than ones in the fie…
Risk of predation and foraging sites of individuals in mixed-species tit flocks
1993
Abstract Abstract. Foraging sites of individual willow tits, Parus montanus, and crested tits, P. cristatus, on spruce were studied in a winter when the risk of predation from pygmy owls, Glaucidium passerinum, was high and in a winter when it was low. Mixed-species flocks consisted of two crested tits (a pair) and three to six willow tits. The risk of predation from owls is likely to be highest on the most exterior tree parts. Female crested tits foraged further out on the branches than other individuals when predation risk was low, but foraged in the safer sites close to the tree trunk when the risk was high. Male crested tits retained both their relative distance to the trunk and their r…
Effect of Willow TitPoecile montanusalarm calls on attack rates by Pygmy OwlsGlaucidium passerinum
2013
One suggested anti-predator function of alarm calls is to deliver a message to a predator that it has been detected. Moreover, giving the alarm call could provide a signal to the predator that capturing the individual giving the alarm is more difficult than capturing its silent group members, as the caller is probably the most aware of the predator's location. In an aviary experiment using stuffed dummy Willow Tits Poecile montanus, we assessed whether an authentic alarm call given by Willow Tit affected Pygmy Owl Glaucidium passerinum prey preference. In the experiment, the Owls attacked only the ‘silent’ dummy individuals, suggesting that alarm calling could offer direct fitness benefits …