78 Syntheosciurus brochusTamiasciurus douglasii (Bachman, 1839)
Douglas’s Squirrel
description: Douglas’s squirrel is a small tree squirrel. Its
dorsa l color at ion v a r ie s f rom ol iv ace ous g r ay to g r ay brow n,
often with a dark or chestnut midline band. In the summer
it has a prominent lateral black stripe (which is faint or ab-
sent in the winter) separating the dorsal coloration from the
underparts, which vary from white or pale buff to yellowish
or reddish orange. The tail is similar in color to the back, but
with more black in it, and is fringed with yellow- or white-
tipped hairs. It has distinct white eye rings and slight ear
tufts that are most evident in the winter.
size: Female—HB 185.0 mm (n = 66); T 145.0 mm (n = 7);
Mass 199.3 g (n = 115).
Male—HB 181.0 mm (n = 2); T 119.0 mm (n = 2); Mass
206.9 g (n = 1).
Sex not stated—HB 189.7 mm (n = 3); T 126.3 mm (n = 2);
Mass 242.5 g (n = 4).
distribution: This species is found in the Coast and Cas-
cade ranges and the Sierra Nevada, from southwestern Brit-
ish Columbia (Canada, but excluding Vancouver Island) to
southern California (USA).
geographic variation: Two subspecies are recognized in
Tamia s c iur u s dougla sii.T. d. douglasii—immediate vicinity of the Pacifi c coast in
Washington and Oregon (USA). It can be recognized by
a yellowish fringe on its tail.Tamiasciurus Trouessart, 1880
This genus contains three species.
natural history: This species is diurnal and crepuscular.
Bangs’s mountain squirrels can be seen on the ground, but
they are secretive, remaining in heavy cover; this species
uses all forest levels frequently. S. brochus nests in cavities
and will forage in the upper canopy for fl owers, fruits, sap,
and bark. Mating occurs in the spring, when six to eight
males will chase the female throughout the canopy. Litter
sizes are two to fi ve young. Individuals appear to remain in
family groups for extended periods and will forage alone or
with a partner. Males and females will travel together, rest
during the day next to each other, and sleep in den cavities
together, suggesting a level of pair-bonding that is extremely
uncommon among tree squirrels.general references: Emmons and Feer 1990; Enders
1953, 1980; Giacalone et al. 1987; F. A. Reid 1997; Wells and
Syntheosciurus brochus. Photo courtesy Gregory E. Willis. Gia calone 1985.