Calving areas are the center of a caribou herd’s distribution (ADF&G 1973). Calving grounds are above timberline or along the coast in rolling hills or foothills dominated by heaths, sedges, and forbs. Summer ranges include alpine and arctic tundra (tussock and sedge meadow). Seek lower elevations during winter to forage on lichens, sedges, and browse plants, including boreal forests (Valkenburg 1999). Other habitats include subartic taiga, mature coniferous forest, semi-open and open bogs, rocky ridges with jack pine, and riparian zone. Black spruce and white spruce (Picea glauca) in pure or codominant stands with lichen-moss understories are heavily utilized in Alaska (Skoog 1968, Joly et al. 2003). Sedge meadows dominated by water sedge (Carex aquatilis), rock sedge (C. saxatilis), and tall cottonsedge (Eriophorum angustifolium) provide year-round forage. Barren ground caribou also utilize willow stands dominated by feltleaf willow (Salix alaxensis), Barclay’s willow (S. barclayi), grayleaf willow (S. glauca), tealeaf willow (S. pulchra), and Richardson’s willow (S. richardsonii). Grasslands dominated by rough fescue (Festuca altaica) with birch (Betula spp.) and willow (Salix spp.) associates are frequently utilized (Skoog 1968). Porcupine herd of northeastern Alaska and northwestern Yukon: females give birth on patches of bare ground within snowfields (Eastland et al. 1989); cows select areas north of the foothills (snow conditions permitting), thereby reducing exposure of calves to predators.
ADF&G. 1973. Alaska’s wildlife and habitat. Anchorage, Alaska. 144 pp. + maps.
Eastland, W. G., R. T. Bowyer, and S. G. Fancy. 1989. Effects of snow cover on selection of calving sites by caribou. J. Mamm. 70:824-828.
Joly, K., B. W. Dale, W. B. Collins, and L. G. Adams. 2003. Winter habitat use by female caribou in relation to wildland fires in interior Alaska. Canadian Journal of Zoology. 81(7): 1192-1201.
Skoog, R. O. 1968. Ecology of the caribou (Rangifer tarandus granti) in Alaska. Berkeley, CA: University of California, Berkeley. 699 p. Dissertation.
Valkenburg, P. 1999. Caribou. ADF&G Wildlife Notebook Series. Http://www.adfg.state.ak.us/pubs/notebook/biggame/caribou.php (accessed 26 March 2007).