318 Tamias amo enusfound over a broad span of elevations, up to about 3000 m.
T. amoenus prefers meadows of forbs, grasses, and sedges or
brushy habitats that are often associated with open stands
of Jeff rey pine (Pinus jeff reyi) or lodgepole pine (P. contorta).
Overall, T. amoenus is a habitat generalist and may coexist
with other mammal species because of this fl exibility. Mul-
tiple studies report signifi cantly higher capture rates of T.
amoenus in logged forests, regenerating stands, and clearcuts
than in primary or mature stands, underscoring this spe-
cies’ preference for open habitat.
natural history: Like many of its congeners, T. amoenus
eats the seeds and fruits of many of the plant species in its
habitat, as well as fl owers, tubers, fungi, vegetation, and
animal material (e.g., bird eggs and insects). It also con-
sumes large quantities of hypogeous (underground) fungi,
for which it probably serves as a signifi cant spore dispersal
agent. Although the yellow-pine chipmunk larder-hoards
large quantities of seeds and other plant material for hiber-
nation, numerous studies show that it regularly scatter-
hoards seeds and may be important for the dispersal of
several plant species (e.g., antelope bitterbrush [Purshia tri-
dentata] and chinquapin [Castanopsis sempervirens]) and
otherwise wind-dispersed pines (e.g. Jeff rey pine [Pinus jef-
freyi] and sugar pine [Pinus lambertiana]). As suggested for
other species of Tamia s, a low availability of mast results in
more time spent foraging and less time devoted to vigilance
and other activities; this, in turn, may infl uence winter
survival. Detailed fi eld and laboratory studies by Vander
Wall and associates also demonstrate how numerous fac-
tors (e.g., masting patterns, seed quality, cache-site selec-
tion, cache depth, risk of pilferage, olfactory capabilities,
spatial memory) infl uence the scatter-hoarding decisions
of T. amoenus, and, in turn, the potential for seed dispersal
and establishment by this rodent.
Population densities average 1.25–7 animals/ha, depend-
ing on location and habitat quality. Like other members of
the genus, T. amoenus is diurna l, but inac t ive during t he w in-
ter months when hibernating. Although grassy nests are
reported in aboveground vegetation, this species usually
burrows belowground, often under stumps, logs, and rocks.
Emergence from hibernation occurs by April, and mating
takes place by early May. Paternity studies suggest a promis-
cuous mating system, with low variability in male mating
success and multiple mates for both sexes. There is also
strong evidence for sperm competition and little evidence
for inbreeding. One litter is produced per year; litter sizes
average four to fi ve. T. amoenus is less able to deal with tem-
perature extremes than other congeners. In T. amoenus, tes-
tosterone levels in plasma appear to reduce glucocorticoid
levels, and thus fat reserves and overwinter survival. This
species is aggressive toward other species of Tamia s, but it is
subordinate to T. townsendii and occasionally dominant over
T. minimus. Such aggression may infl uence the elevational
distribution of these species relative to that of T. amoenus in
some parts of its range. A number of mammals and birds are
reported to prey on yellow-pine chipmunks. Ectoparasites
include the botfl y (Cuterebra), at least seven species of fl eas,
one tick, and one phoretic mite; high fl ea burdens are re-
ported. Surveys of endoparasites are not available, although
this species’ highly granivorous diet probably predisposes it
to few internal parasites.general references: Anthony 1928; Briggs and Vander
Wall 2004; Demboski and Sullivan 2003; Good, Demboski,
et al. 2003; K. M. Kuhn and Vander Wall 2008; A. W. Linzey
and Hammerson 2008f; Morris 1996; Place 2000; Roth and
Vander Wall 2005; Schulte-Hostedde, Gibbs, et al. 2000,
2001; Schulte-Hostedde and Millar 2000, 2004; Schulte-
Hostedde, Millar, and Gibbs 2004; Schulte-Hostedde, Mil-
lar, Gibbs, et al. 2002; T. P. Sullivan and Klenner 2000; T. P.
Sullivan, Lautenschlager, et al. 1999; T. P. Sullivan, Sulli-
van, and Lindgren 2000; T. P. Sullivan, Sullivan, Lindgren,
et al. 2005; Sutton 1992, 1995; Thayer and Vander Wall
2005; Vander Wall 1993a, 1993b, 1993c, 1993d. 1993e, 1995a,
1995b, 1995c, 1995d, 1998, 2000, 2003; Vander Wall, Beck, et
al. 2003; Vander Wall and Peterson 1996; Waters and Zabel
1998.Tamias bulleri J. A. Allen, 1889
Buller’s Chipmunkdescription: T. bulleri has nine dorsal stripes: fi ve black
and four pale (gray or grayish white) stripes. The more me-
dian three black stripes are dark in color, and the outer two
are lighter, browner, and shorter in length. The sides are
brownish yellow; the inside of the ears is rust colored.size: Female—HB 134.0 mm; T 91.5 mm; Mass 74.9 g.
Male—HB 131.9 mm; T 84.6 mm; Mass 66.1 g.
Sex not stated—HB 130.4 m; T 104.8 mm.distribution: This is the southernmost species of the ge-
nus, found in the Sierra Madre in southern Durango, west-
ern Zacatecas, and northern Jalisco (México).geographic variation: None.conservation: IUCN status—vulnerable. Population
trend—decreasing.