Nest Sites and Food Habits of Long-Eared Owls in Southwestern Idaho

Nest-site selection of the Long-eared OwlAsio otusin northwestern Switzerland

“…Data collected here are consistent with the hypothesis that nest sites may be selected as part of an antipredator strategy, as reported in the USA (Marks 1986, Bull et al 1989). Predator avoidance is also an important factor for nest-site selection of Spotted Owls Strix occidentalis (Buchanan et al 1995), as well as for Sparrowhawks (Selas 1996(Selas , 1997.…”

“…This was also observed in the USA (Marks 1986). The average height of nests is typical of the study area (Cercle ornithologique de Fribourg 1993) and of Germany (Block & Block 1987), although other studies report lower nest heights (< 10 m) (Glue 1977, Marks 1986, Tome 1997. A taller tree can be a protection against terrestrial predators, namely martens, and can favour easy nest access (Moorman & Chapman 1996).…”

Density, diet and productivity of Long-eared OwlsAsio otusin the Italian Alps: the importance ofMicrotusvoles

“…Therefore, to assess breeding output, territories were repeatedly visited during April-June to listen for the persistent food-begging calls of fledged young. These leave the nest when about three weeks old to 'branch' in nearby trees, and in the following two or three weeks are extremely easy to detect and count, their calls being easily audible from up to 500 m away (Mikkola 1983, Marks 1986, Korpimäki & Norrdahl 1991. If no such calls were heard in at least three successive visits distanced more than 50 days apart, the pair was assumed to have failed.…”

Feeding Ecology of Sympatric Barn Owls and Long-Eared Owls in Idaho

“…The disparity in prey size selection between the two species resulted primarily from (1) Barn Owl predation on Thomomys, which apparently are too large for Long-eared Owls to capture easily (see Marks and Yensen 1980), and (2) the comparatively minor proportion of Microtus in Long-eared Owl diets. The disparity in prey size selection between the two species resulted primarily from (1) Barn Owl predation on Thomomys, which apparently are too large for Long-eared Owls to capture easily (see Marks and Yensen 1980), and (2) the comparatively minor proportion of Microtus in Long-eared Owl diets.…”