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The marten (Martes americana) is a member of the weasel family (Mustelids). It is closely related to the sable of Asia and northern Europe. The sable is a popular furbearer whose darker pelt fetches a high price. Marten have been intensively harvested in North America, and most of the harvest comes from Canada. In the early 1900s, 60,000 pelts were sold annually in this country but, by 1930, marten populations had decreased. This was due to the pressures of uncontrolled trapping and the reduction of their range during the last century, when much of the land was burned, logged and cleared for agriculture. Now, however, marten are reappearing in good numbers in areas where suitable habitat exists. In fact, recent harvest figures have surpassed previous records for North America.

Marten inhabit most forested areas of Canada, but are no longer found on Prince Edward Island. In the United States, they can be found in the Great Lakes states, in some western states, and in the south as far as northern New Mexico and central California.

The marten has a long slender body, a small head with a short, pointed muzzle, large, rounded ears and dark brown eyes. Its legs are short and its paws have large, furred pads and semi-retractable claws. Its bushy tail is about half the length of its body. Males have an average length of 50 to 63 cm (20 to 25 in) including the tail, and an average weight of 680 to 900 g (1.5 to 2 Ibs). Females average 46 to 56 cm (18 to 22 in) in total length and 450 to 680 g (1 to 1.5 Ibs) in weight. Both sexes have two types of scent glands: the anal gland, located under the tail, and the abdominal gland, found under the skin of the belly. Particularly during the breeding season, marten will drag their bellies over logs and clumps of vegetation to mark their territories. Although individuals may vary from yellow to nearly black, the colour is usually a golden brown. The head is lighter in colour and the legs, darker. The throat and chest have a yellow-orange patch, and the edges of the ears are white. The prime fur has a soft, rich texture except during the summer, when it becomes thin and coarse as guard hairs and much of the underfur are shed. The summer coat is lighter in colour and has a faded, rough appearance. New fur growth begins in late summer and is completed by October.

Life History
Both male and female marten usually reach sexual maturity by the time they are a year old. They breed during July and August, often mating with several partners in one season. Since marten are solitary creatures, it is only during the breeding season that they can be seen in pairs. Birth does not occur until 220 to 276 days after fertilization, and, for most of that time, the egg is in a resting state. This is known as “delayed implantation”. The active pregnancy lasts only 27 days. The kits are born during March and April, and the average litter contains three. The new-born are blind for the first four to six weeks and are covered with fine, soft, yellowish hairs. Wild marten of both sexes usually live to six years of age, and individuals of up to 19 years old have been trapped in Ontario. The young may be distinguished from the old by their skull features.

Marten prefer to inhabit large tracts of mature coniferous and mixed wood forests but avoid burned-over areas. Den sites include hollow trees, under logs, stumps and rock crevices, as well as squirrel nests.

Food and Feeding Behaviour
Marten prey on birds, insects and small mammals, particularly red-backed voles and field mice. Their diet can also include rabbits, squirrels, and chipmunks, carrion of various kinds and fruit.

The marten has a keen sense of smell, sight and hearing. It is full of curiosity, and, because of this, it is easily baited and trapped. Males tend to be more active during the evening, while females tend to be more active during the day. Both sexes can also be active at night. Except during the breeding season, marten live and travel alone. They may den up during storms or periods of extreme cold temperatures. Before and after her litter is born, the female maintains a permanent den. At other times, both sexes like to keep moving. Immature marten have no territory of their own. As adults they mark their ranges with their scent glands. In good habitat, the minimum home range for males is from 2 to 3 square km (about 1 square mi). For females, it is about 1 square km (.37 square mi). Marten are thorough when looking for prey, searching out brush piles and stumps and inspecting every hole and crevice. They can climb trees with ease, but normally hunt and travel on the ground. Although they have been seen swimming even underwater, they seldom leave dry land. In winter, they sometimes tunnel along under the snow as they seek their prey.

Population Changes
In good habitat, there is usually one resident marten for every 4 square km (1.5 square mi). Because of their tendency, especially in juveniles, to move from place to place, the number of marten in a specific area is never completely stable. Populations can double or triple because of the presence of immature marten that have not yet established their own ranges and are just “passing through”. This is especially true during the late summer, when the young begin to leave the family den. Trapping also affects the marten population. Trappers catch two or three times as many males as females, probably because the males cover more ground and are more likely to encounter a trap. Yet, this does not cause the population to become unbalanced. The sex ratio remains equal. This means that females must have a higher natural mortality rate. The young of the year are very vulnerable to trapping. This may be due to their lack of experience or to the fact that they travel more widely than adults may. The greatest numbers of young are caught in October and November. This fact is useful in determining the time of the trapping season. Setting an early season will mean that a large part of the harvest will consist of young, non-breeding animals. Harvesting the immature rather than the adult marten is preferable for two reasons. First, the adults will bear the following spring, while the young will not. Second, the young of the year are far more likely to die of natural causes than the adults that have already established home ranges.

More than one third of the marten harvest in North America is trapped in Ontario. Various management techniques are used to ensure the continued existence of marten in good numbers. Licensing trappers, establishing quotas and varying the length and dates of the trapping season are three of the most familiar. Since marten are easy to trap, steps must be taken to prevent over-harvesting. Ontario has a quota system, which allows each district office of the Ministry of Natural Resources to work with local trappers in setting a limit on the number of marten taken from the area. The quotas are based on local habitat conditions and population trends as well as on the age and sex ratios in past harvests. Research is ongoing to provide more information for use in establishing quotas. Refuges and restocking have enhanced marten populations in the past. Restocking involves live-trapping the animals and moving them to under-populated areas. When populations in surrounding areas were low or non-existent, refuges like Algonquin Park and the Chapleau Game Preserve served as reserve areas from which marten could disperse. Improving the marten’s habitat helps to ensure a sustained yield. Extensive clear-cuts and fires destroy the habitat by eliminating resting sites, hunting areas and overhead cover, and by reducing the food supply. However, milder disturbances, like patch cutting and low intensity fires, do not damage marten habitat and, in some cases, can improve it. The increased shrub growth, which follows, produces more fruit and attracts more of the small mammals on which marten prey. Experienced trappers have found that leaving beaver or other carcasses at marten food sites can increase the carrying capacity of the habitat, especially during the winter.