Outside of southwestern Europe, the next closest association between lagomorphs and this species is in the arid steppe of southern Russia, hares are apparently the primary prey of the local eagle-owls. Little has been published in recent ornithological review, but old studies have indicated that the eagle-owls in this region are so dependent on hares, primarily again the mountain hare species, that cyclical reductions in numbers of the hares are followed immediately by a reduction of the local eagle-owls. A similar phenomenon has been noted in the great horned owl in its association with the snowshoe hare in the American boreal forest. The same prey, the mountain hare, was the most important along the Pechora River in Russia, making up 34.1% of prey numbers, although the general habitat is distinctly different from the steppe, as it consists of mountainous sub-taiga dense forests. Together with sizeable numbers of Eurasian red squirrels and large forest grouse which are the next most significant prey types by number, the mean prey size along the Pechora is presumably extremely large. Although in surrounding arid lowlands the food is almost totally dominated by gerbils, jirds and their kin, in the Pamir Mountains of Tajikistan and Afghanistan, the cape hare (Lepus capensis) was the leading prey species, making up 44% of the prey numbers. In Mongolia, tolai hare (Lepus tolai), of similar size to the cape and Granada hare, were the most significant contributor of prey biomass, making up 30.6% of biomass but only contributed 4% of the prey by number Other than the prior mentioned species, at least five other species of hare have been found as occasional contributors to the eagle-owl's diet. The only other family in the lagomorph order, the pikas, have been found to factor regularly into the diet of Eurasian eagle-owls as well, mainly in the mountainous regions of Asia. Pikas are much smaller than rabbits and hares, averaging amongst the know prey species. One study in Mongolia found that Daurian pikas (Ochotona dauurica) made up 73% by number of the remains. In the Tibetan Plateau, the plateau pika (Ochotona curzoniae) and gansu pika (Ochotona cansus) were the second and third most numerous prey species. The more sizeable large-eared pika (Ochotona macrotis) was the second most regular prey species in the Pamir Mountains, comprising 10.8% of the remains.