Eurasian eagle-owl
Even those near the northern limits of their range, where winters are harsh and likely to bear little in food, the eagle-owl does not leave its native range. There are cases from Russia of Eurasian eagle-owls moving south for the winter, as the icebound, infamously harsh climate there is too severe even for these hardy birds and their prey. Similarly, Eurasian eagle-owls living in the Tibetan highlands and Himalayas may in some cases vacate their normal territories when winter hits and move south. Even in those two examples, there is no evidence of consistent, annual migration by Eurasian eagle-owls and the birds may eke out a living on their normal territories even in the sparsest times.
Dietary biology of the Eurasian eagle-owl
While owls are apparently often killed by Eurasian eagle-owls while actively hunting, diurnal raptors are often ambushed at night at their large, conspicuous nests since they are easily located during hunting forays and the raptors are nearly defenseless in nocturnal conditions. The eagle-owl has been specified as the primary predator of common buzzards, peregrine falcons, common kestrel ("Falco tinnunculus") and black kites. The common buzzard and common kestrel are probably the most often selected diurnal raptors because they inhabit the edges most often hunted by the eagle-owls. Studies have shown that peregrine falcon experience lower productivity in areas where they nest closely to eagle-owls, as the eagle-owls pick off both nestlings and adults by night. However, peregrine populations were not hugely effected except in cases where small reintroductions were attempted of falcons or falcon populations were already rare due to other causes. The northern goshawk is itself a serious predator of other raptors. The eagle-owl is the goshawk's only major predator, although goshawks are not as intensely hunted as are buzzards due to their more deeply wooded preferred nesting habitat.