Northern red-backed voles on the Kenai National Wildlife Refuge fed during the summer on berries of species such as mountain cranberry and bunchberry. They also ate fungi, succulent green plants, and insects. As fungi became plentiful late in the summer, they made up a large percentage of the diet. Mountain cranberry consumption declined as the summer progressed even though berry abundance increased. This suggests that fungi were preferred over mountain cranberries.
Small mammals are the primary means by which hypogeous fungal spores are dispersed.
However, after cover and food resources recover, northern red-backed voles are able to colonize burned areas. Establishment of a permanent population of northern red-backed voles on the burned area did not occur until 4 years after the fire. Northern red-backed voles began to use the burn area starting in July of 1972. However, prior to the summer of 1975 the use of the burned area by northern red-backed voles was intermittent due to insufficient food and cover for overwintering. No berries were produced in the burn until the summer of 1975, and then berry production was considerably lower than that in the unburned control area.