[3][7] The subspecific name honours Orii Hyōjirō, collector of the type specimen in "Uyenai" (植苗) (now part of the city of Tomakomai), old Iburi Province, on 13 March 1920.

[4] While the Siberian flying squirrel (Pteromys volans) at species level may be found across the coniferous forest zone from Finland and the Baltic to Korea, the Hokkaidō population is recognized as a distinct, endemic subspecies.

[4] On Hokkaidō, it inhabits the coniferous, broad-leaved deciduous, and mixed forests, both montane and lowland, and may also be found in windbreaks and groves in urban parks.

[8] The Ezo flying squirrel is entirely herbivorous, feeding on leaves, buds, flowers, seeds, acorns, catkins, and fruits of both broad-leaf trees and conifers, with significant seasonal variation.

), Japanese white birch (Betula platyphylla), and East Asian alder (Alnus japonica); in summer, cherries, mulberries, birch and maple seeds, and the unripe acorns of the daimyō oak (Quercus dentata) and Mongolian oak (Quercus crispula); prior to winter, in order to put on weight—and increase the chance of survival—there is increased foraging of highly nutritious pine nuts; during the winter, birch and alder leaves and buds are consumed.

[4][5][9] Predators include the Ezo red fox (Vulpes vulpes schrencki), Ezo sable [ja] (Martes zibellina brachyura), Ural owl (Strix uralensis), Blakiston's fish owl (Bubo blakistoni), sparrowhawk (Accipiter nisus), black kite (Milvus migrans), and domestic cat (Felis catus).

[5] A study of thirty-six winter nests found Sakhalin fir (Abies sachalinensis) was the preferred choice (52.8%), followed by the painted maple (Acer pictum subsp.

[5][10] Repurposed nests include those of the great spotted woodpecker (Dendrocopos major), Oriental turtle dove (Streptopelia orientalis), and members of the crow family (Corvidae).

[5] Approximately forty days after birth, young leave the nest for the first time and begin to consume solid food.

[11] Using Inau sticks, and praying to the sacrificed squirrel for assistance, he should give the meat to his wife to eat, again without her knowing from what "bird" it was derived.