It also hunts efficiently on the ground, where it seeks out mice, shrews, chipmunks, rabbits, birds and their eggs, amphibians, reptiles, insects, nuts, and fruit. Marten are occasionally the prey of Fishers, Lynx, Coyotes and Great Horned Owls. Marten favour hollowed trees or cavities in piles of rocks for a den, although they may use overturned stumps or brush piles as temporary shelters. The mating season occurs during the summer, and a litter of one to six young is produced the following spring. Habitat loss due to forestry activity exerts the most significant impact on populations in Canada, as in the United States.
Trapping is also a concern.
In Ontario, Domtar is one of many forest companies preparing forest management plans which will consider the sustainability of Marten habitat. In areas where Marten are common, the provincial government has instituted guidelines that require forest managers to determine the area capable of supporting Marten, now or in the future. The study is also investigating Marten usage of the transition zone between these two forest types. In this mark and recapture experiment, researchers insert tiny microchips beneath the skin of trapped Marten. Later, they identify recaptured individuals by running a reader wand over live traps.