Red Squirrel (Tamiasciurus hudsonicus)

County List:

Rule:

Forested or Mixed Forested/Nonforested Landscapes

1st alternative:
      (Oak (Sm Saw or Lg Saw or Uneven))
      or (Assorted Hardwoods (Sm Saw or Lg Saw or Uneven))
      or (Bottomland Hardwoods (Sm Saw or Lg Saw or Uneven))
   containing:
      (Dead Down Woody Debris and Mast and Snags and Living Cavity Trees and Conifer Inclusions)

2nd alternative:
      (Any Upland Conifer (Sm Saw or Lg Saw or Uneven))
      or (Any Upland Mixed (Sm Saw or Lg Saw or Uneven))
      or (Any Lowland Mixed (Sm Saw or Lg Saw or Uneven))
   containing:
      (Dead Down Woody Debris and Mast and Snags and Living Cavity Trees)

Habitat List:

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Literature:

The red squirrel prefers extensive stands of evergreen trees or mixed coniferous/deciduous woodland. It may live in pure deciduous forests, particularly in the southern Great Lakes basin, but even there, it is more likely to take up residence if at least a few conifers grow close by.

A tree cavity is the preferred den site, but if one is not available, the squirrel weaves a basketball-sized nest from leaves and twigs high in a tree. Unlike fox or gray squirrels, the red squirrel occasionally nests on the ground or even underground, especially in the winter.

The favorite food is seeds extracted from cones of spruce, fir, larch, and especially hemlock or pine. In deciduous forests, it eats walnuts, acorns, hazelnuts, and similar foods. During spring and summer, it consumes large quantities of buds, seeds, fruits, mushrooms, and even maple sugar. This species is more carnivorous than gray or fox squirrels and frequently preys on insects, young and adult birds, mice, voles, and young rabbits. In late summer, it caches cones and nuts for winter consumption in large piles stacked next to a stump or hidden in an underground cavity.

Habitat: Coniferous, mixed and occasionally deciduous forests, rural woodlots.

Special Habitat Requirements: Woodlands with mature trees, conifers preferred.

Distribution: The red squirrel inhabits northern cone-bearing evergreen forests, adjacent mixed conifers and hardwoods and, sometimes, pure deciduous hardwoods stands, especially in moist situations.

Habitat Preferences: Many observers consider the red squirrel a denizen of damp, cool, shady, boreal coniferous forest habitats. However, both Hatt and Layne, major contributors to the natural history of the red squirrel, found the species in assorted woody environments ranging from pure cone-bearing coniferous areas to stands of deciduous trees. It is Layne's contention from his New York studies that red squirrels thrive best in abundant coniferous cover and/or seeds. Beckwith writes that the red squirrel joins the gray squirrel in taking over the beech-basswood-maple stage in forest succession; whereas, the fox squirrel holds its own in the oak-hickory association.

In Michigan, red squirrels are most prevalent in mixed evergreen and deciduous forests but can be found in older pine plantations, old orchards, city parks, and school grounds. Quality habitat, according to Layne, consists of stands of ungrazed beech, maple, hemlock, or especially hemlock and white pine.

Behavior: Red squirrels seem much more ubiquitous in selecting den sites than either gray or fox squirrels. The former not only use arboreal refuges - leaf nests and tree cavities - but also den at ground level in logs, rock piles, and underground burrows as well as in barns, houses, and other man-made structures.

Along with the gray and fox squirrels the red squirrel seems to prefer tree cavities to leaf nests, even though these hollows may be in short supply in evergreen forests. Red squirrels will use natural cavities or enlarge and take over holes excavated by woodpeckers. Red squirrels also occupy ground refuges constructed in log piles, rock fences, beehives, and human habitations. Underground burrow systems often open beside old stumps and under clumps of woody vegetation, including hedgerows.

Allen found the red squirrel competed with the fox squirrel for tree cavities; all three tree squirrels probably interact occasionally in this competition.

Food Habits: Red squirrels, like gray and fox squirrels are food opportunist and rely on seasonal foods, in addition to year-around availability of acorns, conifer seeds, and nuts from the autumn production. Smith stressed that red squirrels need high energy foods such as the reproductive products (seeds, nuts, etc.) of conifers, deciduous trees and bushes and the cambium layer of pine trees as providing such needs. It was also his opinion that red squirrels are essentially adapted to exploit conifer seeds and fungi in boreal coniferous forests. Cones of hemlock and white pine are perhaps most preferred by Michigan red squirrels.

Key Components of Habitat: Dense or clumped stands of mature coniferous to deciduous forest; multi-storied stands; suitable nest sites; sufficient moisture/shade for cone storage.

Management Actions to Enhance or Maintain Habitat Quality: Main trees of sufficient size in deciduous forest to provide cavities; maintain coniferous trees in managed mixed forest; preserve mature densely branched trees (e.g. fir) in or adjacent to managed coniferous stands; provide clumped stands ³0.4 ha (1acre) in area of mature conifers with interlocking crowns in intensively managed areas.

Habitat: The red squirrel occurs mainly in coniferous forests of spruce, eastern hemlock, white pine, and balsam fir, but also occurs in mixed forests and deciduous forests. In Alaska, red squirrels are found mainly in white spruce stands and only rarely in black spruce stands. In central Alberta, red squirrels were most abundant in spruce stands (both white and black), less abundant in jack pine, and least abundant in aspen. In eastern North America the red squirrel is abundant in mature hardwood forests containing some spruce, hemlock, or balsam trees, but is rare in pure hardwood stands that do not contain oak, chestnut, or walnut trees. In the Adirondacks, red squirrels are most abundant in spruce stands but are also found in balsam stands and in mixed forests containing spruces.

The principal habitat requirement of the red squirrel is an adequate food supply. Other important features include suitable nest sites, protective cover, and moisture and shade for cone storage. In the boreal coniferous forests the food supply is provided largely by the annual cone crop, which is cached for a winter food supply, and by terminal buds. In hardwood forests, red squirrels have a more diverse food base supplied by a variety of nut-bearing trees.

In eastern hardwood forests, cavities in trees are preferred as nest sites, but outside nests and underground nests are also common. Den trees containing cavity nests varied in diameter from about 12-36 inches and in height from about 20-60 feet. Den entrances ranged from about 7-50 feet above ground. Tree species containing cavity nests included white pine, hemlock, and a wide variety of hardwoods. Leaf nests were found in white pines, red pines, hemlocks, larches, and a number of hardwood species. Trees containing leaf nests ranged in diameter from about 4-16 inches and in height from about 15-70 feet. Outside nests were found from about 12-60 feet above ground. Underground nests were found in burrow systems under decaying stumps, piles of logs, stone fences, and hedgerows. Cavities in trees are rare in coniferous forests, so under ground nests and outside tree nests are commonly used. Where available, spruces will be used as nest trees. Where spruces are not available, those conifers with the greatest branch density will be selected and nests will often be in contact with the trunk. Nests are rarely located in isolated trees or small groups of trees; rather, they are located in trees whose crowns are in close proximity to the surrounding trees. The close proximity of nearby trees provides protection from weather and a variety of escape routes, and it reduces foraging times. The dense stand also provides a damp shaded spot for the cone cache, ensuring that the cones will remain closed and retain their seeds - the squirrel's winter food supply.

In summary, red squirrels are mainly associated with the coniferous forests in northern and western North America but are also common in eastern forests containing some mature conifers or nut-bearing hardwoods. An adequate food supply provided by mature conifers is the important habitat requirement throughout most of the range. However, suitable nest trees or other sites, snags or fallen logs around which the food cache is centered, and a dense stand of trees to provide protective cover and shade for the food cache are also important.

Food Habits: In coniferous forests, red squirrels feed primarily on seeds of conifers and on the reproductive structures of a variety of fungi. In deciduous forests, red squirrels will cache seeds or nuts of oak, hickory, elm, maple, beech, hazel, chestnut, walnut, butternut, sycamore, and tulip trees. Coniferous and deciduous buds are important components of the diet during winter and spring. Feeding preference studies have indicated that red squirrels choose white spruce cones over black spruce cones. Interestingly, the mean energy content of white spruce seeds was significantly higher than that of black spruce seeds. Red squirrels can maintain themselves on a diet of only white spruce seeds but lose weight on a diet of black spruce seeds.

Red squirrels in coniferous forests inhabit single-occupant territories that are defended from conspecifics of either sex year-round. In deciduous forests, red squirrels do not establish exclusive territories but rather have home ranges that overlap broadly. The lack of territoriality in deciduous cover may be the result of a more abundant and diverse food base, which frees the squirrels from dependence on a cached food supply. It may also result from the red squirrel's inability to defend food caches against the large number of avian and mammalian competitors for nuts. Females may defend small zones around nest trees, and both sexes may defend feeding sites. Territoriality is best developed in areas where food is mainly supplied by a few coniferous species and cone production is highly variable. In this situation, territory size is inversely proportional to the amount of available food per unit area. Territory size appears to be sufficiently large to meet the food requirements of the resident during years of low cone production.

Habitat Management: Main habitat requirements of the red squirrel include an adequate food supply, moist shaded areas for the food cache, suitable nest sites, and protective cover. Thus the method used to remove the overstory has a major influence on red squirrel habitat. Monthey recorded low overall use of clearcut areas by red squirrels although clearcut areas formed 1-3 years previously were used more than older clearcut areas, probably because squirrels searched for the seeds of recently felled conifers. Red squirrels were significantly more abundant in undisturbed softwood or hardwood stands than in cutover areas.

Vahle and Patton (in Arizona) demonstrated that red squirrels preferred dense mixed-age stands containing large dominant conifers, snags, and downed logs, and suggested that such areas could be provided by a group selection system of timber harvest. In the group selection system, even-aged aggregations varying in size from just a few mature trees to a stand that is twice as wide as the height of mature trees are removed, leaving residual stands of timber for future harvests. Thus a multistoried (uneven-aged) stand is created or maintained. This system has its natural equivalent in forests that are subject to occasional disturbances that kill scattered trees or large patches and so enable the establishment of different age classes. Vahle and Paton suggested that timber harvesting methods that did not maintain the vertical diversity and grouping of trees (i.e., resulted in even-aged stands) would be less appropriate for red squirrels. One such undesirable system would be even-aged shelterwood harvest. The shelterwood system is essentially one of heavy thinnings or clearcutting over large areas, strips, or patches, with some of the stand left as shelter for reproduction and growth of the new stand. If the system results in large areas of even-aged trees, the habitat will be unfavorable for red squirrels. Other important considerations in habitat management for red squirrels include leaving snags and downed logs as potential nest sites or as potential cache sites, leaving dense groups of trees around existing caches to provide the necessary moist shaded microhabitat, and leaving dense groupings of trees around potential nest trees.