The call notes of the Douglas squirrel are similar to those of the red squirrel but are softer, more slurred. The common call is the long, trilling "burr," loud at first and becoming gradually softer. On hot afternoons in late summer a barking "pauf" note is given. This sound is repeated several times at intervals of a minute or so. It has remarkable carrying power. The danger signal is a loud, explosive "pe-ee." Another common call is a short barking or chirping "bauf" with a musical, questioning sound. This is repeated at intervals of a few seconds when the presence of danger is suspected. At times it, rather than the loud danger signal, is given also when a person is sighted. A low chirping note is often given while the squirrel is busily at work. This is made while the squirrel is moving about. Other calls described are made from a standing or sitting position and are accompanied by a jerk or a flick of the tail. The Douglas squirrel eats seeds of the Douglas fir, seeds of maple, hazelnuts, dogwood berries and mushrooms. The berries of forest shrubs, such as the red huckleberry, salal and Oregon grape, may also be eaten. Two broods of young may be born in a year. The first is born in early June. Embryos found from June 11 to 28 varied in number from 6 to 8. A nursing female was taken as early as June 10, 1938, and one was taken as late as October 10, 1938. Douglas squirrels commonly have a few fleas and 2 to 5 ticks at the bases of the ears. No lice, cases of mange, or serious infestations of parasites have been seen. =Glaucomys sabrinus= (Shaw) Northern flying squirrel [Illustration: FIG. 91. Northern flying squirrel (_Glaucomys sabrinus_), probably from near Seattle, in Woodland Park Zoo, Seattle, Washington, January 28, 1941. (Fish and Wildlife Service photo by Victor B. Scheffer, No. 1137.)] _Description._--The northern flying squirrel is slightly smaller than the red squirrel (_Tamiasciurus_). The head and body measure about 7 inches and the tail about 5 inches. The most distinctive feature is the loose fold of skin that stretches from the wrist of the foreleg to the ankle of the hind leg. The fur is extremely soft and plushlike. It is not separated into guard hair and underfur, and because all hairs are of approximately the same length, the fur appears extremely sleek. The fur of the tail is of the same texture as that on the body but is dorso-ventrally compressed. The eyes are large and dark. The color of the upper parts varies from reddish brown in some races to brownish gray in others. The underparts are buffy gray.