Marten have long, slender bodies with pointed faces, small prominent ears, short legs, and long furry tails. They are roughly the size of their more aquatic relative, the mink, attaining lengths up to 25 inches and weights up to 2.5 pounds.
Males are slightly larger than females. Although color can vary considerably, marten fur is often described as reddish-brown on the torso becoming darker, almost black on the legs and tail.
Marten have lighter colored heads often tinged with gray and have a prominent, black vertical mark on the inner corner of each eye. The throat and chest area are distinctively buffed colored. Marten feet have fully furred soles and semi-retractile unsheathed claws.
Marten prefer woodlands composed predominantly of softwoods or mixed woods. They are generally associated with older aged forests having complex physical structure such as downed, dead wood and thick vegetation; however, they will use a variety of habitat types if food and cover are available.
Downed woody material such as stumps, logs, brush and slash provide important refuge sites for nesting, resting and foraging marten. Large openings in the forest are avoided by marten especially in the winter. Marten are adapted to deep snow conditions giving them a competitive edge over the more aggressive fisher. This advantage may in part explain why marten are more often found in the higher elevation habitats prone to deep and prolonged snow.
Female marten mature at one and a half years. They prepare a lined nest in the cavity of a tree or in a rock den. Although marten breed any time between late June and early September, development of the embryo does not begin until February or March. This phenomenon, known as "delayed implantation", is believed to be a mechanism by which the pregnant female can abort the fertilized egg should her physical condition deteriorate through the harsh winter conditions.
Post-implantation gestation is 27 days. The litter of one to five young is born blind and virtually hairless with each kit weighing only one ounce. The young reach their full length at three months but do not gain their full weight for several months. Female marten are known to breed at least to the age of 14½. Adult male martens do not aid in raising the young.
Marten have varied diets corresponding to the seasonal availability of food. They are opportunists and will commonly feed on a variety of amphibians, reptiles, small mammals, insects, birds, eggs, and berries. Larger prey such as snowshoe hare and ruffed grouse also make up a significant portion of their diet.
In winter, marten favor habitats with ample access to subniveanfood sources such as red-backed voles. Fluctuations in marten populations are known to follow cycles in mast crops illustrating the importance of these crops and the small mammal populations they influence as food sources.
Marten remain on Vermont's endangered species list and are protected accordingly. A marten recovery plan was adopted in 1990 at the outset of the reintroduction effort. Although some of the information in this plan is outdated with respect to specific reintroduction-related recommendations, much of the plan remains relevant today.
The apparent establishment of marten in Vermont in recent years has prompted a re-evaluation of this recovery plan, and work is now underway to better understand Vermont's marten population and to implement the conservation measures identified in the plan.
The existence of marten in Vermont presents several conservation challenges, and recovery efforts will need to be varied accordingly. A few of the more significant challenges are highlighted below:
Determining the source of marten in Vermont.
Understanding the source of marten is critical to making an informed assessment of the factors influencing the species' ability to persist in the state. Are these at-risk isolated populations or are they the result of natural dispersal?
Assessing the distribution and abundance of marten in Vermont.
Understanding the distribution will allow managers to more effectively focus conservation efforts.
Identifying, protecting, and managing suitable marten habitat in Vermont.
In the absence of sufficient quantities of suitable habitat, the success of recovery efforts in the state will be limited.
Providing for the protection of marten in Vermont.
Identifying and addressing specific potential threats, such as incidental trapping and/or competition with fisher, will aid in the recovery effort. Enforcement of existing laws, the dissemination of relevant information and the development of best management practices for trapping are all key components of this work.
With respect to the latter of these ongoing recovery efforts, there has been considerable concern raised about the occurrence of incidentally trapped marten in the state. While it is true marten are occasionally taken in fisher traps, it is important to fully understand the overall implications of these relatively rare events.
Much of the critical data currently available in Vermont stems from the collection of incidentally trapped marten including important population sex and age structure data, genetics, and distribution.
The rate of incidental take of marten by fisher trappers is extremely low averaging only 2.5 animals per year since 2004.
Marten have continued to expand their range in Vermont despite occasional incidental take.
Continuing to manage fisher populations in areas where marten exist is an important recovery effort and the failure to do so may have serious consequences for marten.
Marten tend to occur in relatively remote, higher elevation habitats that are not easily accessible to trappers.
Trappers have proven to be indispensable partners in the effort to recover marten providing valuable information about the species; in Vermont and demonstrating a commitment to continued cooperation with the Vermont Fish & Wildlife Department.
Efforts are underway to identify effective tools and techniques for minimizing the incidental take of marten and the implementation of the resulting best management practices is an anticipated outcome of this work.
According to one of Vermont's earliest natural historians, Zadock Thompson, marten were once very plentiful in most parts of the state but by the 1850s were "confined to the most mountainous and woody portions" of the landscape. The widespread deforestation and unregulated harvest of fur-bearers characteristic of the 1800s took its toll on marten, and by the early 1900s the species was deemed extinct in the state. Marten were legally classified as an endangered species in Vermont in 1972 in accordance with the state's endangered species act.
In recognition of the species inherent ecological value, the Vermont Fish & Wildlife Department and the U.S. Forest Service endeavored to restore a marten population in the state. Beginning in 1989, a total of 115 individual marten was live-trapped in Maine and New York and released at several different sites in the Green Mountain National Forest. However, extensive post-release monitoring and follow-up surveys conducted throughout the 1990s indicated the reintroduction effort had failed.
Although some of the released marten established home ranges within nearby suitable habitat, as was hoped, more were documented to have dispersed from the region altogether. One released marten, for example, was road-killed in Candia, New Hampshire some 70 miles away, while another was similarly found dead on the road just outside of Hartford, Connecticut 100 miles from its release site. The furthest extent a released marten was documented to have dispersed was one that was trapped in Rangeley, Maine during the marten trapping season in 1997, 150 miles from its release site.
In addition to outright dispersal, competition with a burgeoning fisher population throughout the 1990s was also believed to contribute to the restoration effort's apparent failure. During the winter of 1994-1995, 12 remote cameras were deployed throughout ideal marten habitat in the vicinity of original release sites. Although marten were detected at two of these sites, fisher were detected at 11.
Three years later, a similar study using 47 remote cameras detected no marten while fisher were documented at 37 of the sites confirming the belief that a viable population of marten had not become established in Vermont.
Despite the presumed failure of the southern Vermont reintroduction effort, evidence collected in the early 2000s indicated the existence of a small marten population in the northeastern corner of the state. Beginning in 2001, the Vermont Fish & Wildlife Department started receiving citizen reports of marten sightings throughout Essex County.
In 2004, the first verifiable occurrence of marten was documented in Averill, Vermont. As of 2014, a total of 60 occurrence records have accumulated resulting in the confirmation of at least 27 individuals.
Most interesting is the fact that since 2010, seven of the confirmed marten occurrences have originated from southern Vermont. It appears that marten have now become established in two distinct populations in the state. Is it possible the reintroduction efforts was not a failure after all or are these animals the product of natural recolonization.