フクロウ
Ural owls regularly live concurrently in different parts of their range with other owl species. Most sympatric species also share a preference for small mammals, largely voles, especially when they occur in relatively northerly temperate places such as the haunts of the Ural owls. Thus, the Ural owl is frequently considered to be a competitor with sympatric owl species. Most especially, the Ural owl has often being compared and studied in areas of sympatry with its close cousin, the tawny owl. The tawny owl may co-exist with Ural owls today in many parts of the latter’s European distribution, including southern Fennoscandia, eastern and central Europe and European Russia. The dietary habits of the two species are largely concurrent, as in Uppland, Sweden, where prey species and groups were almost identical in rank of importance to their diets (i.e. field vole, water vole, "Apodemus" species, birds and frogs). On Mount Krim in Slovenia, both tawny and Ural owls took the same primary prey species but the tawny owl was shown to be adaptable to alternate prey during the low part of the vole population cycle while the Ural was less adaptive to alternate prey. The diets were largely similar between tawny and Ural owls as well in the Bavarian Forest of Germany but the tawny species took proportionately fewer field voles and more insects, and was estimated to take prey weighing on average 43% less than that taken by Ural owls. In Finland, food niche breadth for Ural owls overlapped about 73% with the tawny owl but the mean prey size was more than twice as much for the Ural owl, for tawny vs for Ural, and the tawny owl was recorded to take non-mammalian prey significantly more so than Ural owls. In Belarus, tawny owl prey sizes were between 31 and 49% smaller on average (utilizing two different calculation methods) than those of Ural owl but the smaller species had a considerably greater food niche breadth, which averaged 12.96 for tawnys and 5.48 for Urals. Compared to the tawny owl, the Ural owl is considerably larger in size and talon size (which is about 30% greater in the Ural), with the talon shape further indicating their different ecological roles, being proportionately shorter and more curved in tawny owls in accordance with its more varied diet and heavier and straighter in the Ural owl for dispatching relatively larger mammals. It is known that when ranges overlap between tawny and Ural owls, the Ural owl tends to dominate and sometimes kill the tawny owl. In Slovenia, Ural owls actually responded more consistently to recorded calls of tawny owls (40% of call exposures causing a vocal or physical response) than to recordings of calls of their own species (34% of call exposures eliciting a response). However, cases of interspecific killing between the species are fairly infrequent, and recent study indicates that the tawny owl’s relatively checkered distribution in northerly areas such as Fennoscandia is not likely due to this competition but rather due to the regional habitat type favoring the Ural owl. The tawny owl is not as well suited to taiga habitats as is the Ural species and locally are less suited to alternate nest sites (i.e. nesting in areas lacking tree cavities or nest boxes, whereas the Ural can locally also use old bird nests and tree stumps). Warming average temperatures in Fennoscandia have appeared to effect many owl species negatively due to the limiting nature on vole cycles, but the tawny owl, being confined to the south, has had the most decreased effect locally due to the lowering vole numbers (and despite their general ability to adapt to different prey) while the Ural owl, in central Finland at least, is not yet showing as drastic a negative effect due to this. Similarly, the tawny owl and Ural owl are largely segregated by altitudinal range and habitat in eastern Europe (i.e. the Carpathian mountains) and Poland, with little evidence that this is due to interspecific competition or predation but rather the suitably of the montane habitats. Here the tawny owl tends to occur at lower elevations while the Ural owl occupies the foothill forests at higher elevations. Generally, despite higher densities of the Ural in some mountainous parts of central and eastern Europe, the tawny owl is far more numerous in all countries of that region than the Ural owl. In Slovakia, 13.3% of Ural owl territories overlapped with those of tawny owls, a relatively low overlap given the overall environment. Despite the Ural owl’s presumed dominance, in Slovenia, a tawny owl was observed to fiercely attack a Ural owl until it left the vicinity, though it is not clear whether this was a territorial encounter or antipredator mobbing. In Poland, during post-dispersal in winter tawny owls were able to temporarily utilize parts of Ural owl territories, taking advantage of the Ural owls less aggressive behaviour outside of the breeding season.