Yellow-pine chipmunks, Tamias amoenus, are found in the northwestern United States and southwestern Canada. They occur throughout Idaho, Washington, and Oregon (excluding coastal areas), as well as northern Nevada and northern Utah, western Wyoming and western Montana, and mountainous areas of California. In Canada, yellow-pine chipmunks occupy most of southern British Colombia and the mountainous regions of southwestern Alberta.

Biogeographic Regions: nearctic (Native )

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: Western North America, from central British Columbia and southwestern Alberta south to Yolla Bolly Range and Mammoth Pass in California, northern Nevada, and northwestern Utah, east to central Montana and western Wyoming; elevations of 975-2900 m in California (Sutton 1992; Hoffmann et al., in Wilson and Reeder 1993).

Yellow-pine chipmunks are small compared to other members of the genus Tamias. They measure 181 to 245 mm in length, and can weigh between 30 and 70 g. Females tend to be larger than males.

These animals have five black, evenly-spaced, longitudinal stripes down the back. The three dorsal stripes extend from shoulder to rump, whereas the two lateral strips extend only to mid-body. The pale stripes are usually white or grayish. Body color varies depending upon subspecies. Tamias amoenus affinis has a pinkish-cinnamon colored body, T. a. monoensis is a cinnamon buff, T. a. luteiventris is sayal-brown, T. a. felix is ochraceous tawny, and T. a. ludibundus is tawny. The underside of the tail ranges from pinkish-cinnamon to grayish-yellow to sayal-brown. The ears are whitish behind and black in front.

Yellow-pine chipmunks can be distinguished from similar species by the genital bones of both sexes. They can also be distinguished based upon size and color. Lodgepole chipmunks are larger than yellow-pine chipmunks, have bigger ears, and more sharply contrasting stripes. The outer stripes of lodgepole chipmunks are also wider than the inner stripes. Least chipmunks are smaller than yellow-pine chipmunks, and also paler in color. Yellow-pine chipmunks are smaller and redder than Unita chipmunks. Unita chipmunks also have grayer shoulders and heads.

Range mass: 30 to 73 g.

Range length: 181 to 245 mm.

Sexual Dimorphism: female larger

Average basal metabolic rate: 0.5 W.

Length: 25 cm

Weight: 73 grams

See Sutton (1995).

• Terrestrial

Yellow-pine chipmunks are most common in brushy coniferous forests, but can be found in a broad range of habitat types including areas with rocky outcrops, chaparral, and meadows. They occupy areas that are dominated by shrubs such as service berry (Amelanchier), snowberry (Symphoricarpos), mountain mahogany (Cercocarpus), currant (Ribes), antelope brush (Purshia), and buckbrush (Ceanothus).

Yellow-pine chipmunks require logs, snags, rock crevices, or stumps for nesting, in addition to shrubs and ground litter for cover.

Yellow-pine chipmunks typically occur at altitudes ranging from 600 to 2,800 m, however in Washington they have been recorded at elevations of up to 4,300 m.

Range elevation: 600 to 4,300 m.

Average elevation: 2,800 m.

Habitat Regions: temperate ; terrestrial

Terrestrial Biomes: chaparral ; forest ; mountains

Other Habitat Features: riparian

Comments: Generally in brushy areas interspersed with herbaceous vegetation and open conifer stands; shrubs typically present include snowberry, chinquapin, mountain mahogany, antelope brush, currant, and buckbrush (Sutton 1992). Found among logs, brush, and rocky outcrops. Also in brushy areas between subalpine forest and alpine tundra, and in alpine areas themselves. Digs burrows 7-21" deep. Constructs grass nest in burrow under stump, log, or rock; also nests above ground in woody vegetation.

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Yellow-pine chipmunks are mostly omnivorous. They consume at least 59 species of seeds, plants, fruits, fungi, corms, and insects. They are also known to eat small mammals, bird eggs, and roots. They use their cheek pouches to carry conifer seeds and other foods to their burrows.

These chipmunks forage both on the ground and in trees. Foraging is done during the day and from spring to fall. In the fall, they begin storing food in caches for winter. Winter caches of up to 68,000 items, ranging from seeds to bumble bees, have been recorded.

Animal Foods: mammals; eggs; insects; terrestrial non-insect arthropods; terrestrial worms

Plant Foods: leaves; roots and tubers; seeds, grains, and nuts; fruit; flowers

Other Foods: fungus

Foraging Behavior: stores or caches food

Primary Diet: omnivore

Comments: Diet consists of seeds, fruits, green foliage, flowers, roots, buds, bulbs, tubers, fungi, and small animals. Caches food in burrow and in scattered pits dug in soil surface.

Yellow-pine chipmunks are important dispersers of the seeds of various conifer species. They also contribute to the food base of many different carnivore species.

Ecosystem Impact: disperses seeds

Species Used as Host:

• none identified

Mutualist Species:

• none identified

Commensal/Parasitic Species:

• Rickettsia rickettsii
• Rickettsia rhipicephali
• Cuterebra emasculator
• Acarus monopsyllus
• Yersinia pestis
• Borellia hermsii

Yellow-pine chipmunks usually live in underground burrows, which help conceal them from predators. The black and white stripes on the back of these animals help to camouflage them in open forests where sharp shadows are cast by the sun. They also have, to some extent, a system of watch where one chipmunk looks out for predators and warns the others with alarm vocalizations. This is mostly observed in more open areas where chipmunks are more exposed to predators.

Predators include coyotes (Canis latrans), goshawks (Accipiter gentilis), long-tailed weasels (Mustela frenata), badgers (Taxidea taxus), bobcats (Lynx rufus), rattlesnakes (Crotalus viridis), and sparrow hawks (Falco sparverius).

Known Predators:

• Coyotes (Canis latrans)
• goshawks (Accipiter gentilis)
• long-tailed weasels (Mustela frenata)
• badgers (Taxidea taxus)
• bobcats (Lynx rufus)
• rattlesnakes (Crotalus viridis)
• sparrow hawks (Falco sparverius)

Anti-predator Adaptations: cryptic

Home range is a few acres, parts of which may be used seasonally (see Sutton 1992). In Washington, density was fairly stable over 3 years at 1.25/ha (see Sutton 1992). Easy prey for many kinds of predators. Competitive interactions with other chipmunk species may limit habitat use. Effective dispersal agent for Jeffrey pine seeds (Vander Wall 1992; see also Vander Wall, 1993, Oecologia 96:246-252).

Yellow-pine chipmunks have 10 different recognizable vocalizations. Most of these calls are alarm calls to alert conspecifics of predators. When greeting conspecifics, they first touch noses, then smell the sides of the face and neck, and last they sniff the anus. Visual signals, such as body posture, are important in communication.

Communication Channels: visual ; tactile ; acoustic ; chemical

Perception Channels: visual ; acoustic

Comments: Hibernates late fall-early spring. May become lethargic during cold summer weather. Stores little energy as body fat; awakens periodically in winter to feed on stored seeds (Banfield 1974, Sutton 1992).

Yellow-pine chipmunks have been known to live up to 5 years 2 months in the wild. Young have a 30% survival rate. Once they emerge from the den at about 6 weeks of age, they are easy prey for a variety of predators. Adults have a summer survival rate of 33% to 88% and a winter survival rate of 97%.

No information was available on the lifespan and survival rate of captive yellow-pine chipmunks.

Average lifespan

Status: wild: 5 years.

Average lifespan

Status: wild: 3 years.

Yellow-pine chipmunks are polygynandrous. Females are in estrous for one day each year. They use vocalizations to attract mates a few days before the onset of estrous. On the day of estrous, females are typically pursued by two to six males in what is called a “mating chase”. A female mates with multiple males during this mating chase. All sexually mature males and females mate during the mating season, which occurs in late April or early May.

Mating System: polygynandrous (promiscuous)

Female yellow-pine chipmunks are in estrous for one day and breed only once per year during late April to early May. Average gestation period is 30 days, after which a female usually gives birth to a litter of 3 to 8 babies. Young are highly altricial at birth and remain in the burrow until they are weaned at six weeks of age. Young begin to disperse and find their own burrows at about 8 to 12 weeks of age. They reach sexual maturity at 12 to 23 months.

Breeding interval: Yellow-pine chipmunks breed only once per year.

Breeding season: Breeding occurs in late April or early May.

Range number of offspring: 3 to 8.

Average number of offspring: 4 to 5.

Range gestation period: 28 to 40 days.

Average gestation period: 30 days.

Average weaning age: 45 days.

Range time to independence: 2 to 3 months.

Range age at sexual or reproductive maturity (female): 12 to 23 months.

Range age at sexual or reproductive maturity (male): 12 to 23 months.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); fertilization ; viviparous

Average birth mass: 2.62 g.

Average number of offspring: 5.19.

Pregnant females make nests of leaves, grass, lichen, and feathers in burrows that are about 1.5 m below ground or up to 18 m in trees. Babies are altricial and depend on the mother for food and protection until they emerge from the burrow at about 6 weeks of age. Males do not contribute to the care of the offspring. At about 8 weeks of age, young of both sexes disperse to find their own nests and burrows for winter.

Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning: Female, Protecting: Female)

Breeds in early spring. Average litter size is 5 (Washington) to 6 (California); 1 litter/year in Washington Cascades (Kenagy and Barnes 1988). Young are born from mid-May to early June (Banfield 1974), weaned in about 6 weeks; first appear at surface in June in Washington Cascades; first breeds at 1 year (Kenagy and Barnes 1988). May live up to 5 years.

Yellow-pine chipmunks are common in the northwestern United States and southwestern Canada. The species has no special status.

US Federal List: no special status

CITES: no special status

IUCN Red List of Threatened Species: least concern

Canada

Rounded National Status Rank: N5 - Secure

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Yellow-pine chipmunks have been identified as hosts for the disease vectors responsible for Colorado tick fever, tick-borne relapsing fever, hantavirus pulmonary syndrome, and Rocky Mountain spotted fever richettsia. They also become heavily infested with bot fly warbles and fleas that are known to carry plague.

Destruction by yellow-pine chipmunks of young conifers intended for timber harvest has been documented, however the overall damange is insubstantial.

Negative Impacts: injures humans (causes disease in humans , carries human disease); causes or carries domestic animal disease

Like most chipmunks, yellow-pine chipmunks are favored among nature lovers. This species is less destructive of young conifers (often harvested by humans for timber) than other small mammals.

Positive Impacts: research and education

Comments: Sciurid mycophagy may play important role in forest ecology (Maser and Maser 1988).

Comments: Formerly included in genus Eutamias, which recently was included in the genus Tamias (Levenson et al. 1985; Jones et al. 1992, Hoffmann et al., in Wilson and Reeder 1993). Based on patterns of variation in ectoparasites (Jameson 1999) and molecular phylogenetics (Piaggio and Spicer 2001), the North American mammal checklist by Baker et al. (2003) placed all North American chipmunks (except Tamias striatus) in the genus Neotamias.

Thorington and Hoffmann (in Wilson and Reeder 2005) noted that chipmunks could be legitimately allocated to one (Tamias), two (Neotamias, Tamias), or three (Tamias, Neotamias, Eutamias) genera; they chose to adopt the single-genus (Tamias) arrangement.