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.
Boreal owl
The boreal owl breeds in dense coniferous forests across northern North America and Eurasia, and in mountain ranges such as the Alps and the Rockies. It lays 3–6 eggs in a tree hole. Across much of Europe, and to a lesser extent in Asia and North America, naturalists and biologists put up nest boxes for these and other small owls.