23.

Eastern Heather Vole

Phenacomys ungava

French: Phénacomys d'Ungava / German: Ostliche Heidekraut-Wiihimaus / Spanish: Topillo de brezo oriental

Taxonomy. Phenacomys ungava Merriam, 1889, “Fort Chimo, Ungava, Hudson Bay Territory,” Canada.

Four subspecies are recognized.

Subspecies and Distribution.

P.u.ungavaMerriam,1889—C&EManitoba,Ontario,Quebec,andNNewfoundland,Canada,andNEMinnesota,USA.

P.u.crassusBangs,1900—extremeNEQuebecandSNewfoundland,Canada.

P.u.mackenziiPreble,1902—fromSYukon,SNorthwestTerritories,andSNunavutStoCBritishColumbiaandSCAlberta,andEthroughNSaskatchewanand NManitobatoHudsonBay,Canada.

P. u. soperiR. M. Anderson, 1942 — SE Alberta, C Saskatchewan, and SW Manitoba, Canada.

Descriptive notes. Head—body 83-112 mm, tail 23-40 mm, ear 12—-13-5 mm, hindfoot 17-20 mm; weight 15-47 g. The Eastern Heather Vole is a smallto medium-sized, with short tail thatis less than one-half of head-body length. Face and snout of adults and occasionally subadults are distinctive, with yellow, ocher, cinnamon, or red tints that contrast with rest of head and dorsum. Ears are small and relatively hairy, with yellow or tawny tips and tuft ofstiff, orange hair anterior to ear. Dorsum is thick,soft, and grizzled dull brown, with yellow or tawny wash. Sides are lighter, and venter may be grayish white. Juveniles are darker. Tail tends to be bicolored. The Eastern Heather Vole has eight mammae: four inguinal and four pectoral. Unlike most other arvicolines, molars are rooted in adults. Chromosomal complementis 2n = 56, FN = 58.

Habitat. Boreal forests, with composition varing across Canada. In the east, habitat associations used by Eastern Heather Vole are centered on coniferous forests of pines or spruces. In central Canada, jack pine ( Pinus banksiana, Pinaceae) forests that have heavy understories of heath shrubs had highest densities of Eastern Heather Voles, while disturbed and mixed forests had much lower numbers. In Ontario, forest with high understory cover of sheep laurel ( Kalmia angustifolia), lowbush blueberry ( Vaccinium angustifolium), and Canadian blueberry (V. myrtilloides), all Ericaceae, were used. Farther west, closed and open spruce ( Picea sp., Pinaceae), deciduous forest, and shrub habitats are identified as major habitat types. Willow ( Salix sp., Salicaceae), spruce and willow associations, shrub birch ( Betula sp., Betulaceae) and meadows, and balsam poplar ( Populus balsamifera, Salicaceae) habitats had highest numbers of Eastern Heather Voles. Captures of Eastern Heather Voles have also occurred in rocky outcroppings surrounded by wet tundra and in climax tundra, open peat bogs, and muskegs.

Food and Feeding. The Eastern Heather Vole eats berries, leaves, twigs, bark, and roots that it caches year-round. Caches vary depending on availability of nearby plants, but they can include willow, blueberry ( Vaccinium sp.), soapberry ( Shepherdia sp., Eleagnaceae), dwarf birch ( Betula glandulosa), bearberry ( Arctostaphylos sp.), and crowberry ( Empetrum sp.), both Ericaceae), and fireweed ( Epilobium sp., Onagraceae).

Breeding. Males and female Eastern Heather Voles breed in June-August. Eastern Heather Voles generally do not sexually mature until their second summer. Females that do reproduce in theirfirst year have smallerlitters. Mean gestation is 21 days (19-24 days). Litters have 2-8 young (average 4-5). Oneto two litters are produced annually.

Activity patterns. The Eastern Heather Vole is active year-round and mostly at twilight or night. There is less frequent activity during the day . Rainy, foggy, or windy nights will elicit bouts of foraging activity.

Movements, Home range and Social organization. Life span of the Eastern Heather Vole is up to four years based on studies of cranial morphology and tooth wear. Regular or cyclic population fluctuations are not known, but densities of Eastern Heather Voles can change substantially over time. In a study in Manitoba, captures of the Eastern Heather Vole increased from zero in the first year to 192 in the fifth year and decreased to a single capture in seventh year. The Eastern Heather Vole uses different nests in winter and summer. Winter nests often are located below snow and aboveground at bases of bushes, stumps, or rocks. Summer nests are smaller and found under boards, mounds left by rotten stumps, peat, or rock and in stumps, logs, or roots of small trees.

Status and Conservation. Classified as Least Concern on The IUCN Red List.

Bibliography. Banfield (1974), Bradley, Ammerman et al. (2014), Braun et al. (2013), Foster (1956, 1961), Hall (1981), Musser & Carleton (2005), Youngman (1975).