Records for the northwestern deer mouse in Alaska concentrate in the Southeast, the temperate rainforest belt of the Panhandle and its outlying islands, within Tongass National Forest. That’s coastal Sitka spruce and western hemlock forest, salmonberry thickets, and damp beach fringe, not the Interior’s dry boreal forest or the Arctic tundra farther north; this mouse is a rainforest specialist first.
It’s active only after dark, working the forest floor at night and holing up by day in a burrow, stump cavity, or old bird nest lined with shredded plant fiber. Roughly half its diet is invertebrates, rounded out with fungi, carrion, seeds, and soft fruit such as salmonberries and huckleberries as they ripen through the wet Southeast summer. Dense undergrowth and a thick litter layer on the forest floor matter more to this mouse than any single plant species growing there.
Reports climb from June through September and fall off through the wetter, darker months, tracking when researchers and hikers are out in the field as much as the mouse’s own routine. Records here stay comparatively sparse for a species with this much rainforest habitat, partly because it looks nearly identical to the far more widespread deer mouse and confirmed identification often needs a skull or genetic check rather than a photo.
Full species profile
