American Marten (Martes americana)

County List:

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Forested Landscapes

Habitat Requirements may be distributed across the NEIGHBORHOOD

      (Spruce/Fir (Pole or Sm Saw or Lg Saw or Uneven))
      or (Hemlock (Sm Saw or Lg Saw or Uneven))
      or (Jack Pine (Sm Saw or Lg Saw or Uneven))
      or (Any Upland Mixed (Pole or Sm Saw or Lg Saw or Uneven))
    containing:
      (Stand/Gap Openings 
      and Dead Down Woody Debris 
      and Snags 
      and Living Cavity Trees)
   neighboring:
      (Northern White Cedar (Pole or Sm Saw or Lg Saw or Uneven))
      or (Black Spruce (Pole or Sm Saw or Lg Saw or Uneven))
      or (Any Lowland Mixed (Pole or Sm Saw or Lg Saw or Uneven))
      or Treed Bog
   containing:
      (Stand/Gap Openings 
      and Dead Down Woody Debris 
      and Snags 
      and Living Cavity Trees)

Habitat List:

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Literature:

The marten primarily resides in closed, coniferous woodlands underlain by a lush growth of shrubs and forbs and appears less frequently in mixed stands. It occurs in upland forests of spruce, fir, or hemlock as well as in cedar swamps. Logging clear-cuts, burned areas, and other open sites are useless to a marten.

In winter it often searches for prey in snow-covered spaces found beneath woody debris. Other than females with young, a marten has no fixed shelter; it rests in a tree hollow, rotting stump, or rock pile or simply on an exposed branch. A maternity den is usually a leaf-lined tree cavity or rock crevice.

Ground-dwelling rodents, especially red-backed voles, are preferred food, although a marten commonly eats red squirrels and northern flying squirrels as well. Other prey animals include shrews, hares, birds, reptiles, and amphibians. Beetles and bugs form a small but consistent, part of the diet, and carrion is eaten whenever it is available. In summer, the marten adds fruits, particularly blueberries and raspberries, to its meaty menu.

Habitat: A diversity of wooded habitats including coniferous forests of fir, spruce, and hemlock, dense mixed hardwood-conifer forests, cedar swamps. Softwood dominated mixed stands preferred in undisturbed forest in Maine. In the Adirondacks, martens are found in 30-year-old mixed stands, and in pole and mature hardwood stands at elevations of 530m to 1463m.

Special Habitat Requirements: Den sites (hollow trees or logs are most commonly used). Martens seem to have no permanent den sites.

Habitat Preferences: Biologists have noted that marten in the western parts of its North American range appear to thrive in stands of spruce and fir, consisting chiefly of mature trees having a canopy coverage of at least 30%. In contrast, marten in eastern parts of its range not only utilize conifer forests (including cedar swamps) but also mixed stands of both conifers and hardwoods. In Michigan, Wood noted that beech-maple forests in the vicinity of Whitefish Point in Chippewa County sustained marten populations. Clear-cutting practices and severe fires apparently reduce forest habitat quality drastically for marten. Selective cutting and scattered fires provide some habitat diversity and can increase marten food supplies in the form of small mammals, birds, and fruits. Ideally, marten are best adapted to mature northern forests, probably mostly coniferous, in which the extensive canopy maintains a shaded and moist interior with a substrate well-strewn with windfalls and other forest debris.

Behavior: The young are born and reared in a cavity (lined with vegetation) in a hollow tree, an opening in a fallen log or stump, or in a rock pile. The selection of this site is the responsibility of the pregnant female. Otherwise, martens have no fixed or permanent dens. Temporary resting places, often in exposed locations, are used through the year, mostly as daytime retreats. These sites are located in live tree hollows, or tops of branches, in logs, in stumps, in ground burrows, and in rock piles. Tree resting sites include hemlock, yellow birch, and balsam fir.

Key Components of Habitat: Relative dense mature to old-growth coniferous to mixed deciduous forest; mosaic of forest and successional habitats; suitable den sites (e.g. snags, downfall, rock crevices) in association with forest cover.

Management Actions to Enhance or Maintain Habitat Quality: Maintain high degree of interspersion between intensively managed stands and stands managed with sufficiently long rotation to provide structural and vegetative diversity similar to old-growth; ensure snag availability; maintain vegetation in riparian areas and ridgelines for dispersal; maintain large debris and downfall.

Habitat: Martens prefer mature conifer or mixed wood forests, although they will tolerate a variety of forest habitats if food and cover are available. Severe disturbance of a forest by extensive clearcutting or large fires will seriously reduce its habitat value for martens for as many as 15 years. Snyder reported that clearcut areas in Newfoundland had not regenerated adequately even after 23 years. Perhaps these differences in regeneration time merely reflect differences in tree species and latitudes. These disturbances will also change habitat values for prey. Lesser disturbances, however, may increase habitat values by creating better habitat for prey and better den sites. In California, Hargis and McCullough recommended a diversity of tree sizes and age classes to provide hunting sites and protective cover under different snow conditions, and suggested that such mixed-age stands can support more prey species. In Maine, islands of conifers within clearcut areas and partially cut mixed stands were heavily used during both summer and winter. Snyder found that martens in Newfoundland seldom used clearcut areas or residual stands less than 37 acres but used larger residual stands. She recommended that the distance between these residual blocks be nor more than 820 feet and that uncut strips at least 328 ft wide be left along waterways. Because clearcutting lowers the carrying capacity of an area for martens, resulting in larger home range sizes and lower population densities, Soutiere recommended that clearcutting be done in small blocks or patches and that 25% of the area be retained in forest cover that has a basal area of at least 109 ft²/acre of pole stage and larger trees.

Raine found that during winter martens in Manitoba seldom traveled on frozen lakes but made extensive use of alder bogs and old beaver meadows, especially if they had good access to subnivean space. Koehler and Hornocker in Idaho found that openings that are avoided during winter may be used during summer and fall if food and cover are available. Martens in California showed preferences for areas with low overhead cover (<10 feet above the snow) but were not selective for dense forest stands.

Allen reviewed the literature and prepared a winter habitat suitability index (HSI) model for martens in the boreal coniferous forest of the western United States. He assumed, perhaps incorrectly, that food availability would not be limiting for martens if adequate cover was present. For the purposes of the model, the most significant limiting factors were the percentage of canopy closure (>30%) and the successional stage of the stand (pole-sized or larger trees). The coniferous composition of the overstory (>25%) and the percentage of the ground covered by fallen trees and stumps (20-50%) were also important.

If subnivean access routes such as those provided by slash, stumps, or downfall, which give access to prey below deep snow; are limited, as in the case of clearcut areas, this may be more restrictive on marten winter densities than the actual density of available prey. Large old trees and large logs are important as den sites for martens.

Abstract: Both species preferred coniferous types and avoided deciduous ones. Even though American martens and fishers overlapped in cover type preference, they did not overlap in patch size selection. American martens selected larger patch sizes of the preferred type than did fishers.

See Literature Cited section within the dissertation for specific citations.

Habitat Use - Literature Review: American martens in Alaska, Yukon Territory, Manitoba, Washington, Idaho, Wyoming, Central Rocky Mountains, Minnesota, Ontario, New York, Maine, and Newfoundland preferred coniferous or mixed coniferous-deciduous forest cover types. Within preferred types, American martens used stands considered to be of late successional stage, old-growth, or mature age class. American martens avoided clear-cuts and recently logged areas. Thompson and Colgan observed greater survival and reproduction rates for American martens in old-growth forests than in post clear-cut forests in Ontario.

Snyder and Bissonette found that American marten populations in Newfoundland were denser in undisturbed forests with large core areas. American martens were sensitive to the size of residual stands, preferring residual forest patches >15 ha in size. Koehler and Hornocker found the greatest American marten activity in forested stands with >30% closure. Bateman found that American martens preferred forested stands with overstory densities >75%. Snyder and Bissonette reported that their most successful trap sites were associated with trees ³15 cm dbh and overhead cover of 50-100%. Within forested stands, American martens used dead down woody material, stumps, snags, rock piles, cavity trees, and red squirrel middens as den and rest sites, subnivean access points, and foraging areas. Female American martens in Maine used 40-70 cm dbh logs or cavities in mature trees of declining vigor for their maternal dens.

Appendix A.

• Bateman (1986), Western Newfoundland
  Selected mixed balsam fir/white birch and coniferous forests with high (³ 76%) overstory density. Martens investigated subnivean tunnels by blow-downs and stumps.
• Buskirk (1984), South-central Alaska
  Selected red squirrel middens. High use of old-growth stands of white spruce or mixed white spruce/paper birch for resting sites, reflected red squirrel habitat preference.
• Buskirk et al. (1989), Central Rocky Mountains
  Selected subnivean sites associated with coarse woody debris, including logs and stumps. Use of spruce-fir stands by adults was greater than expected and use of lodgepole pine stands was less than expected.
• Campbell (1979), Bridger-Teton NF, Wyoming
  Marten did not utilize altered areas within 1 year following timber harvest. Highest level of marten activity associated with mature Englemann spruce/subalpine fir. Marten winter hunting in dense, mature coniferous forest with actual hunting below the snow.
• Clem (1977), Algonquin region of Ontario
  Marten captures and recaptures were restricted to large conifer stands.
• Corn and Raphael (1992), Central Rocky Mountains, Southern Wyoming
  Martens used existing openings in snow, created primarily by logs at low snow depths and by small live spruce and fir trees at greater snow depths. Sites of marten subnivean entry had greater percent cover and total volume of coarse woody debris, greater numbers of log layers, greater volume of undecayed and moderately decayed logs, less volume of very decayed logs, and fewer small root masses than surrounding forest stands.
• de Vos (1951), Ontario
  Not found in recently logged or burned-over areas. Mixed or pure stands of trembling aspen and paper birch are poor habitat. Later successional stages are more suitable because of the amount of cover and the presence of denning holes in trees.
• de Vos (1951), Chapleau Game Preserve, Ontario
  Martens were more abundant in forests that were more mature, closer to the climax stage, and consisting of a high percentage of conifers.
• de Vos and Guenther (1952), Washington and Chapleau Game Preserve, Ontario
  In both areas, movements restricted to main watersheds. Washington - fir, cedar, and hemlock types preferred. Ontario - cedar swamp type preferred.
• Francis and Stephenson (1974), Algonquin Provincial Park, Ontario
  Marten preferred forest types containing a high proportion of conifers in both summer and winter. More martens were captured in mixed wood and conifer stands. These stands, especially the conifer stands, had a more open ground cover with numerous logs and stumps. Three active dens were found and all were in conifer stands. Two dens were found among boulders within 91 m of small lakes. One was in a hollow cedar log on top of a hemlock ridge. Hollow logs were frequently used as day-dens and were usually located in conifer or mixedwood stands. Significantly more tracks were observed in conifer stands and significantly fewer in hardwood stands.
• Fredrickson (1990), Newfoundland
  Marten of all ages avoided clearcuts during logging operations and for the first 9 months afterward. Resident kits made significantly greater use of clear-cuts than older residents.
• Hargis and McCullough (1984) Yosemite National Park, California
  Marten selected dense cover less than 3 m above snow level and used tree trunks and other objects for access to the subnivean zone. Logs served as den sites and hunting areas, and rocks were used for scent and urine marking. Mixed-age forests were important in furnishing subnivean access and protective cover.
• Katnik (1992), Maine
  Mixedwood stands were selected over pure conifer or pure deciduous stands. Pure conifer habitats were unique - most uncut stands were on wet sites and previously harvested stands were even-aged with little understory.
• Koehler and Hornocker (1977), Selway-Bitterroot Wilderness, Idaho
  The highest activity when snow depths were normal was in stands having an Englemann spruce/subalpine fir overstory, canopy cover greater than 30%, mesic habitat type, and an overstory age greater than 100 years.
• Lensink (1953), Interior Alaska
  The climax spruce forest seems essential. Open areas are usually avoided. Leaning or nearly prostrate deadfalls were frequently climbed.
• Martin and Barrett (1983), Northern Sierra Nevada, California
  Snags were found to represent 23% of all dens located. Types of den sites included; snags, stumps, logs, the canopy of trees, willow clumps, other brush, rock slides, and subnivean dens of unknown structure.
• Masters (1980), Adirondack Mountains, New York
  The resting sites were in mixed coniferous deciduous forest. All sites were at least 1.7 m above ground and were in trees (2 in cavities, 3 on branches).
• Mech and Rogers (1977), Northeastern Minnesota
  Most of the daytime resting sites were in stands of conifers, many of which included some white birch and/or aspen. A high percentage of marten captures and sightings were also in conifer dominated areas or mixed stands. Twelve of 13 marten resting sites were in ground burrows, rock piles, or rock crevices and one marten was located in the branches of a jack pine.
• Raine (1981), Southeastern Manitoba
  Marten preferred coniferous ridges and avoided rivers and lakes in all winter periods. Access to subnivean spaces was important.
• Sherburne and Bissonette (1994), Yellowstone National Park, Wyoming
  Marten require subnivean access for cover, prey access, and homeothermic reasons. Coarse woody debris (CWD) provides structure that intercepts the snowfall, creating subnivean tunnels, interstitial spaces, and access holes. CWD and relative prey biomass contributed to selection of subnivean access points. Canopy cover, percent ground cover, and snow depth were not related to access point use. Marten appeared to be able to discriminate between access points with high prey levels and those with low prey levels.
• Slough (1989), Yukon Territory
  Transplanted marten typically occupied late seral or climax coniferous forests, although they freely traversed alpine tundra, open forests, a burn, and large rivers.
• Snyder and Bissonnette (1987), Western Newfoundland
  10.5% of captures were in clearcuts<15 years old while 89.5% of captures were in residual stands. Capture rates were greatest in residual stands 25 to 34.9 ha in size. Based on snow tracking, marten seldom used clearcuts and used residual stands >25 ha and undisturbed forests in proportion to their occurrence, but the use of smaller residual stands <25 ha was greater than expected. Residual stands 15 to 24.5 ha appear to be most preferred during winter while during summer and fall, trapping indicated that residuals of 25-34.9 ha were most frequently used. Larger residual stands and undisturbed stands (>15 ha) are important habitat components for marten in extensively clearcut areas. Successful trap sites usually had trees with dbh ³15 cm dbh and overhead cover 50-100%.
• Soutiere (1979), Maine
  In undisturbed forests, marten preferred softwood-dominated mixed stands. In the partially harvested forests, tracks were found in all cover types in proportion to the occurrence of cover types. Marten rarely used the 0-15 year old clearcut areas, but the associated lightly cut hardwood stands and islands of uncut softwoods were heavily used. Harvesting methods that maintain a residual stand of 20-25 m²/ha basal area in pole and larger trees provide adequate habitat for marten.
• Spencer (1987), Northern Sierra Nevada, California
  During periods of <100% snow cover, live trees were used most frequently as resting sites although they were used less than expected based on availability; relative to availability snags were used most. Snags used by martens were almost exclusively large firs that retained their bark. Live trees used by martens were primarily large lodgepole pines. During periods of complete snow cover, all resting sites were beneath the snow; live trees were not used. Logs provided 52% of subnivean rest sites but snags and stumps were used more, relative to their availability. Cavities in decayed wood beneath snow, especially those used by Douglas' squirrels as cone caches, seemed preferred for winter resting sites.
• Spencer et al. (1983), Northern Sierra Nevada, California
  Below 2,050 m elevation, marten strongly preferred riparian lodgepole pine associations and selected against brush, mixed conifer, and Jeffrey pine associations. Riparian areas were used more for activity than resting, and mixed conifers were used more for resting than activity. In the upper basin, marten strongly preferred red fir associations both for resting and activity. Marten selected for tall, dense forest stands that were near meadows and that had many large snags, stumps, and logs. Marten preferred stands with 40-60% canopy closure at both resting and foraging sites and avoided stands with <30% canopy closure.
• Steventon and Major (1982), Maine
  Uncut softwood islands and partially cut mixed stands were heavily used by marten during summer and winter. Regenerating clearcuts were used less than expected although marten foraged there for red raspberries in late summer. 25% of the home range of a radio-collared female was in clearcut while for 3 males, 16-50% was in clearcuts. Winter resting sites were cavities in large decayed stumps or logs and in the crowns of conifers during the summer months. Although marten relied on the uncut and partially cut stands within the commercially clear-cut forest, they were apparently able to tolerate and make seasonal use of extensive areas of regenerating clear-cuts within their home ranges.
• Taylor and Abrey (1982), Algonquin provincial Park, Ontario
  Martens spent proportionately more time in predominantly coniferous (>50%) habitats than hardwood habitats.
• Thompson (1994), Manitouwadge, Ontario
  Marten density indices were about 90% greater in uncut forests than in logged forests. Marten resident in uncut forest rarely used adjacent logged forests. Resident marten in un-logged forests had higher mean ages, were more productive, and suffered lower daily natural and trapping mortality than those in logged forests.
• Thompson and Colgan (1994), Manitouwadge, Ontario
  Marten experienced greater survival and production rates in old growth forests than in post clear-cut forests. Marten in uncut forests captured up to 119% more prey biomass than in logged forests, depending on prey populations. Access to the subnivean zone was more available in uncut forests than in logged forests.
• Wynne and Sherburne (1984), Maine
  Both male and female martens avoided hardwoods and nonforested types, and females showed a preferential use of softwood stands. All resting sites used by males were in tree canopies, commonly in witches brooms varying in size and density but typically 3-10 m above ground in firs 12-28 cm dbh. Five of 6 maternal dens were in hollow cedar logs or overmature cedar trees (40-70 cm dbh). The remaining den was in a mature sugar maple.