Unlike other members of the squirrel family, flying squirrels are completely nocturnal. They are seen in the daytime only when frightened from their retreats. Homes consist principally of old woodpecker holes or other cavities in trees. They are said to build outside nests, similar to those of tree squirrels, but I have found none of these in Washington. The animals can be frightened from their holes by pounding on the bases of trees in which their nests are situated. Certain holes seem to be preferred nesting places. Near Cottage Lake, King County, two flying squirrels were taken from a woodpecker hole in succeeding years. Cowan (1936B: 58) discovered remains of 14 nests of flying squirrels in a single hollow tree near Alta Lake, British Columbia. According to Cowan, hollow trees are used in winter but the young are born in outside nests of shredded bark and lichens. The young usually number 3 and are born in May and June. [Illustration: FIG. 92. Distribution of flying squirrel in Washington. A. _Glaucomys sabrinus oregonensis._ B. _Glaucomys sabrinus fuliginosus._ C. _Glaucomys sabrinus columbiensis._ D. _Glaucomys sabrinus latipes._ E. _Glaucomys sabrinus bangsi._] Only once have I heard the voice of a flying squirrel. Near Dewey Lake, Yakima County, the squirrels were unusually abundant in the black hemlock and Douglas fir forests of the mountain sides. Here a birdlike twittering note caught my attention and occasional dark, sailing shapes were glimpsed against the clear sky. Eight traps set in the afternoon and visited at 11 p. m. held two flying squirrels. In the morning another was in a trap. Seemingly the squirrels are active most of the night. The food consists principally of conifer seeds and probably other nuts, seeds, and fruit. They eat the meat bait of traps set for fur bearers and probably eat the eggs of birds. =Glaucomys sabrinus oregonensis= (Bachman) _Pteromys oregonensis_ Bachman, Jour. Acad. Nat. Sci. Philadelphia, 8:101, 1839. _Sciuropterus alpinus oregonensis_ Rhoads, Proc. Acad. Nat. Sci. Philadelphia, p. 324, June, 1897. _Sciuropterus alpinus olympicus_ Elliot, Field Columb. Mus. Publ. 30, zoöl. ser., 1:225, February 1, 1899 (type from Happy Lake, Clallam County, Washington). _Glaucomys sabrinus oregonensis_ Howell, N. Amer. Fauna, 44:44, June 13, 1918. _Glaucomys sabrinus olympicus_ Howell, N. Amer. Fauna, 44:49, June 13, 1918. _Type._--Obtained "in pine [= conifer] woods of the Columbia near the sea" by J. K. Townsend in 1839. Probably near St. Helen, Columbia County, Oregon (Rhoads, 1897:324). _Racial characters._--Small size, rich color.