Petaurista caniceps 111tions. Hardwood forests are clearly preferred over those of
conifers. Based on spotlight counts, it is estimated that P.
alborufus is signifi cantly more abundant in hardwood for-
ests than in conifer forests, and that it is less abundant than
P. petaurista in conifer stands. There is also signifi cant sea-
sonal variation in the abundance of P. alborufus in hardwood
forests, with the highest densities occurring in the fall (0.44
animals/ha) and the lowest observed in winter (0.22 ani-
mals/ha). In forests where P. alborufus is sympatric with P.
petaurista, both use the same tree species, but P. alborufus
appears to reside higher in the canopy.
natural history: Little information is available on this
species. It is known to nest in hollow trees and cliff crevices.
P. alborufus is noct urna l, a nd it is repor ted to g lide over 400 m.
Although some consider it to be a folivore, its diet is highly
omnivorous and includes seeds, nuts, and fruits; leaves and
other vegetation; and insects and other animal material.
This species is reported to be sympatric with several other
sciurids, including Hylopetes alboniger, Petaurista philippensis,
P. petaurista, and Tr o g o p t e r u s x ant hip e s. In Taiwan, where two
of these species are often found in the same forests, it is sug-
gested that diff erences in body size (P. petaurista = 989–1597 g;
P. alborufus = 1223–1930 g), along with abundant food re-
sources, allow the two to coexist, partitioning nest cavities
and resting sites and thus avoiding competitive interactions,
which are reported to be uncommon. In most sightings in
trees, these squirrels were found at heights of more than 10
m, and none were sighted at less than 3 m above the ground.
The mating behavior of P. alborufus was observed only in
June. Vocalizations by this species, described as high-pitched
whistles, were produced less frequently and were qualita-
tively diff erent from those made by P. petaurista, which were
described as low-pitched sounds. Their reproductive rate is
assumed to be low (less than two young per litter), as in other
members of the genus.
general references: Lee 1998; Lee, Progulske, et al. 1986,
1993; Oshida, Lin, Masuda, et al. 2000; A. T. Smith and Xie 2008.
Petaurista caniceps (Gray, 1842)
Gray-Headed Flying Squirrel
description: Petaurista caniceps diff ers from P. elegans by
the absence of dorsal spots. This species has a grayish dor-
sum, a white throat, and a whitish brown venter. The base
of the ears is light brown, and the sides of feet are orange.
size: Sex not stated—HB 300–370 mm; T 360–400 mm.
distribution: This species is found in Nepal, Bhutan, and
from India into Myanmar and southcentral China.geographic variation: None. There is some question
whether this is a distinct species, or just a subspecies of
P. elegans.conservation: IUCN status—least concern. Population
trend—stable.habitat: Little information is available for this species. P.
caniceps is found in montane oak-rhododendron (Quercus,
Rhododendron) and conifer forests, at elevations usually be-
tween 2100 and 3600 m.natural history: These squirrels are reported to feed on
rhododendron leaves, buds, and conifer cones. They nest in
tree cavities in rhododendron trees and conifers, but they
are also known to construct leaf nests from ferns. Vocaliza-
tions, described as long cries, should aid in locating the ani-
ma ls in surveys. A lthough little is known about its reproduc-
tive behavior, litter sizes are assumed to be one to two young,
as in other members of the genus. A new genus and species
of fl ea (Smitipsylla maseri) has been collected from P. caniceps
in Nepal. This species is also known to host larval ticks.general references: Hoogstraal and Mitchell 1971; R. E.
Lewis 1971; A. T. Smith and Xie 2008.