Index of Species Information

WILDLIFE SPECIES:  Tamiasciurus hudsonicus

Introductory

WILDLIFE SPECIES: Tamiasciurus hudsonicus
AUTHORSHIP AND CITATION : Sullivan, Janet. 1995. Tamiasciurus hudsonicus. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/ []. Revisions: 18 July 2013: DeGraaf, Richard M.; Rudis, Deborah D. 2001 citation corrected to DeGraaf, Richard M.; Yamasaki, Mariko. 2001. ABBREVIATION : TAHU COMMON NAMES : red squirrel pine squirrel TAXONOMY : The currently accepted scientific name for the red squirrel is Tamiasciurus hudsonicus Erxleben. There are 25 accepted subspecies [13]. ORDER : RODENTIA CLASS : Mammal FEDERAL LEGAL STATUS : The Mount Graham red squirrel (T. h. ssp. grahamensis)is Endangered [45]. OTHER STATUS : Information on state- and province-level protection status of animals in the United States and Canada is available at NatureServe, although recent changes in status may not be included.


WILDLIFE DISTRIBUTION AND OCCURRENCE

WILDLIFE SPECIES: Tamiasciurus hudsonicus
GENERAL DISTRIBUTION : The range of the red squirrel extends from Quebec and Ontario west to Alaska; south in the Appalachian Mountains to Tennessee; and south in the Rocky Mountains to New Mexico [6]. ECOSYSTEMS : FRES10 White-red-jack pine FRES11 Spruce-fir FRES14 Oak-pine FRES15 Oak-hickory FRES18 Maple-beech-birch FRES19 Aspen-birch FRES20 Douglas-fir FRES21 Ponderosa pine FRES22 Western white pine FRES23 Fir-spruce FRES24 Hemlock-Sitka spruce FRES25 Larch FRES26 Lodgepole pine STATES :
AK AZ CO CT DE ID IL IN IA KY
ME MD MA MI MN MT NH NJ NM NY
NC ND OH OR PA RI SC SD TN UT
VT VA WA WV WI WY
AB BC MB NB NF NT ON PQ SK YT
BLM PHYSIOGRAPHIC REGIONS : 5 Columbia Plateau 6 Upper Basin and Range 7 Lower Basin and Range 9 Middle Rocky Mountains 10 Wyoming Basin 11 Southern Rocky Mountains 12 Colorado Plateau 13 Rocky Mountain Piedmont 15 Black Hills Uplift 16 Upper Missouri Basin and Broken Lands KUCHLER PLANT ASSOCIATIONS : K001 Spruce-cedar-hemlock forest K002 Cedar-hemlock-Douglas-fir forest K004 Fir-hemlock forest K005 Mixed conifer forest K008 Lodgepole pine-subalpine forest K011 Western ponderosa forest K012 Douglas-fir forest K013 Cedar-hemlock-pine forest K014 Grand fir-Douglas-fir forest K015 Western spruce-fir forest K016 Eastern ponderosa forest K017 Black Hills pine forest K018 Pine-Douglas-fir forest K019 Arizona pine forest K020 Spruce-fir-Douglas-fir forest K021 Southwestern spruce-fir forest K022 Great Basin pine forest K028 Mosaic of K002 and K026 K093 Great Lakes spruce-fir forest K094 Conifer bog K095 Great Lakes pine forest K096 Northeastern spruce-fir forest K097 Southeastern spruce-fir forest K099 Maple-basswood forest K100 Oak-hickory forest K102 Beech-maple forest K103 Mixed mesophytic forest K104 Appalachian oak forest K106 Northern hardwoods K107 Northern hardwoods-fir forest K108 Northern hardwoods-spruce forest K111 Oak-hickory-pine forest SAF COVER TYPES : 1 Jack pine 5 Balsam fir 12 Black spruce 13 Black spruce-tamarack 14 Northern pin oak 15 Red pine 16 Aspen 18 Paper birch 19 Gray birch-red maple 20 White pine-northern red oak-red maple 21 Eastern white pine 22 White pine-hemlock 23 Eastern hemlock 24 Hemlock-yellow birch 25 Sugar maple-beech-yellow birch 26 Sugar maple-basswood 27 Sugar maple 30 Red spruce-yellow birch 31 Red spruce-sugar maple-beech 32 Red spruce 33 Red spruce-balsam fir 34 Red spruce-Fraser fir 35 Paper birch-red spruce-balsam fir 37 Northern white-cedar 38 Tamarack 40 Post oak-blackjack oak 51 White pine-chestnut oak 52 White oak-black oak-northern red oak 53 White oak 55 Northern red oak 78 Virginia pine-oak 107 White spruce 201 White spruce 202 White spruce-paper birch 204 Black spruce 205 Mountain hemlock 206 Engelmann spruce-subalpine fir 208 Whitebark pine 209 Bristlecone pine 210 Interior Douglas-fir 211 White fir 212 Western larch 213 Grand fir 215 Western white pine 216 Blue spruce 218 Lodgepole pine 219 Limber pine 223 Sitka spruce 224 Western hemlock 225 Western hemlock-Sitka spruce 227 Western redcedar-western hemlock 228 Western redcedar 230 Douglas-fir-western hemlock 237 Interior ponderosa pine 251 White spruce-aspen 253 Black spruce-white spruce 254 Black spruce-paper birch SRM (RANGELAND) COVER TYPES : 109 Ponderosa pine shrubland 409 Tall forb 809 Mixed hardwood and pine PLANT COMMUNITIES : The red squirrel inhabits coniferous forests, mixed conifer-hardwood and occasionally hardwood forests, and rural woodlots [6,19,13]. In western North America red squirrels occur in white spruce (Picea glauca) and black spruce (P. mariana) stands [13,34], Douglas-fir (Pseudotsuga menziesii) forests [22] and pine (Pinus spp.) forests [41]. In Alberta red squirrels occur in quaking aspen (Populus tremuloides)-balsam poplar (P. balsamea) stands with scattered white spruce and black spruce [19]. They also occupy habitats dominated by jack pine (Pinus banksiana) with occasional stands of white spruce. Tamarack (Larix laricina) bogs and black spruce bogs are usually occupied only for periods by juvenile red squirrels searching for suitable territories [13,24]. In Wyoming red squirrels are present in continuous whitebark pine (P. albicaulis), Engelmann spruce (Picea engelmannii)-subalpine fir (Abies lasiocarpa), and lodgepole pine (Pinus contorta) forests [18]. In Colorado red squirrels favor lodgepole pine forests over open stands of ponderosa pine (P. ponderosa) [13]. They are also found in Douglas-fir and in stands transitional between Douglas-fir and ponderosa pine. Their absence from ponderosa pine stands may be a result of interspecific competition with Abert's squirrels (Sciurus aberti). Outside the range of Abert's squirrel, red squirrels are more common in ponderosa pine stands (i.e., in Black Hills National Forest, South Dakota, and Medicine Bow National Forest, Wyoming) [11]. In Arizona and Utah red squirrels prefer fir and spruce forests and are more rarely found in ponderosa pine forests [13]. They are closely associated with old-growth Douglas-fir, white fir (A. concolor), and blue spruce (Picea pungens) stands [27]. Red squirrels are common in low-elevation mixed species forests in central Arizona [46]. In eastern North America red squirrels are abundant in mature hardwood forests containing some mature spruce (Picea spp.), eastern hemlock (Tsuga occidentalis), or balsam fir (A. balsamea), but are rare in pure hardwood stands that do not contain oaks (Quercus spp.), hickories (Carya spp.), or walnuts (Juglans spp.) [25,53]. In the mountains of Virginia red squirrels occur in Table Mountain pine (Pinus pungens)-oak forests [45].

BIOLOGICAL DATA AND HABITAT REQUIREMENTS

WILDLIFE SPECIES: Tamiasciurus hudsonicus
TIMING OF MAJOR LIFE HISTORY EVENTS : Diurnal Activity: Red squirrels are diurnal and active year-round. Peak activity occurs 2 hours after sunrise and just before sunset, but red squirrels are active most of the daylight hours [25]. Movement: Rusch and Reeder [34] reported that red squirrels move from quaking aspen and pine stands to spruce stands in the spring. Fall movements are largely those of juveniles moving away from denser populations of adults in spruce stands. Breeding Season: Red squirrel breeding season varies with latitude and elevation. Generally, the breeding season peaks from March to August, but breeding may begin as early as January and continue as late as October. Mating is promiscuous [13,25]. Nesting and Litter Size: Female red squirrels prefer to nest in natural tree cavities or abandoned woodpecker (Picidae) holes. If none are available they build a leaf [25] or grass nest [27] in the crotch of a limb high on a densely foliated tree, or use a fallen tree, rock pile, underground burrow, or man-made structure. There are usually four or five young per litter (range: one to eight). Generally there is only one litter per year, but occasionally a female bears two litters in one year [25]. Development of Young: Red squirrel young are born naked and blind. By 6 days there is noticeable fur growth and by 20 days there is a good covering of dorsal fur. Their eyes open at 27 to 35 days. They are mostly furred by about 8 weeks. The young red squirrels begin making limited excursions from the nest at 6 to 7 weeks, and forage at a greater distance by about 10 weeks [25]. Weaning occurs at about 7 to 8 weeks in New York [25] and about 10 weeks in Alberta [24]. Dispersal usually begins at about 12 to 14 weeks [25]. Female red squirrels in Canada usually do not breed until their second year. Males develop scrotal testes their first spring but it is not known whether they breed at that time [24]. Dispersal of Juveniles: Juvenile red squirrels disperse in the fall in search of suitable territory [21]. In Alberta initial movements are circular; unsuccessful juveniles usually return to the natal territory until they are successful or are killed. Occasionally juveniles will appropriate the mother's territory [24]. Survival of juveniles depends on establishment of a territory with a food supply adequate for the entire winter [22]. Juveniles surviving their first winter tended to be relatively far away from the natal territory. They appeared to have acquired larger territories than juveniles that died, with middens that were constructed by previous owners [24]. Red squirrels tend to disperse and establish territories in relation to major resources (mature cone-bearing trees) [22]. In south-central British Columbia relocation of resident adult squirrels a substantial distance from the study site allowed researchers to monitor red squirrel recruitment rates. In the fall red squirrel population density recovered to control levels on four out of six sites; immigrants were mostly juveniles. In the spring, breeding red squirrel population density recovered to control levels on five out of the six sites; these sites were also colonized by juveniles in the fall [21]. Mortality and Longevity: In Alberta average annual mortality was 67 percent for juveniles, 34 percent for adult yearlings, and 61 percent for older adults [19]. Larsen and Boutin [24] reported annual adult survivorship for red squirrels in Alberta as 67 to 71 percent. Captive red squirrels have lived at least 9 years and wild red squirrels have lived at least 10 years [25]. PREFERRED HABITAT : Red squirrels require mature coniferous trees as a source of cones and seed [6]. The best cone production occurs in 200- to 300-year old Douglas-fir, 40- to 300-year old white fir, and 150- to 200-year-old Engelmann spruce. The best seed-producing stands of blue spruce (Picea pungens) are 50 to 150 years old [31]. In central Colorado red squirrels were present in closed stands of mature conifers [36]. In west-central Colorado red squirrel caches were more abundant in conifer-dominated stands than in mixed stands or in stands dominated by quaking aspen [35]. In Ontario red squirrel tracks were more abundant in uncut forest than in regenerating stands of various ages with brushy understories [44]. In two study sites in central British Columbia red squirrels were twice and over five times as abundant in unthinned stands of 20-year-old lodgepole pine than in thinned stands. They were most abundant in mature stands. It was suggested that the 20-year-old stands represented marginal habitat that served as a sink area for excess juvenile red squirrels [41]. Home Range: Red squirrel home range size varies with sex, age, and habitat quality. Older red squirrels and females tend to have larger home ranges. In lodgepole pine forests home ranges varied in size from 0.7 to 2.0 acres (0.3-0.8 ha); in mixed hardwood-conifer stands home ranges varied from 6.5 to 11 acres (2.6-4.5 ha) [31]. Home ranges of adult males in New York averaged 6.03 acres (2.4 ha) and ranged from 0.47 to 10.76 acres (0.2-4.3 ha) [25]. Davis [5] reported home ranges of 3.2 acres (1.3 ha) for males and 3.7 acres (1.5 ha) for females. Obbard [53] summarized other data on red squirrel home ranges. Territoriality and Population Density: Red squirrels actively defend a territory [18]. Gurnell [15] estimated that defended territories were 60 to 100 percent of the home range in lodgepole pine forests. In British Columbia spruce-fir and hemlock-cedar (Thuja spp.) forests adult territories averaged 2.2 acres (0.9 ha) at low elevations and 1.3 acres (0.5 ha) at high elevations [52]. There are two types of defended areas: most if not all red squirrels in Alberta defend a winter food cache, which is usually abandoned during the summer, and some red squirrels defend a "prime" territory which has an adequate food supply year-round. One-quarter to one-third of adults defend a prime territory [19]. In New Brunswick, where red squirrels are scatterhoarders instead of larderhoarders, territories encompassing the entire food supply are defended from conspecifics [7]. Smith [52] reported that defended red squirrel territories in coniferous forests ranged from 0.5 to 3 acres (0.2-1.2 ha). Davis [5] reported red squirrel population density of 4 squirrels per 25 acres in mixed jack pine-black spruce stands and 23 red squirrels per 25 acres in white spruce forest. In southwestern Yukon Territory red squirrel population densities of 27 per 25 acres (10 ha) and 17 per 25 acres were observed in white spruce forest interspersed with willow (Salix spp.)-dominated meadows [29]. Many studies, reviewed by Klenner and Krebs [22], indicated that red squirrel population density varies with cone crops. Zasada and others [51] also suggested a relationship between red squirrel density and the periodicity of white spruce cone production in Alaska since red squirrels are dependent on white spruce cones for the majority of their food. Rusch and Reeder [34] reported that summer populations fluctuated between 67 and 151 red squirrels per 2,500 acres in mixed habitats. Sullivan [40] reported that red squirrel population density in British Columbia increased with food supplementation indicating that food availability was limiting population density. In south-central British Columbia food supplementation (feeders that were kept full of sunflower [Helianthus spp.] seeds) in Douglas-fir and in white spruce forests resulted in increases in red squirrel population densities. The amount of change was greatest in the population occupying the Douglas-fir stands, a low density population. Recruitment rates were very high initially, but decreased with increasing population density. Each population increased to approximately the same density, suggesting that the factor regulating the maximum population density is not food supply but territoriality. When feeders were removed, population density declined to control levels in about 6 months [22]. COVER REQUIREMENTS : Nesting: Red squirrels prefer natural cavities or abandoned woodpecker holes for nesting. When these are not available a leaf or grass nest is constructed near the top of a tree with dense foliage. Occasionally red squirrels use abandoned burrows of other species [6]. Nest trees in Arizona have crowns that interlock with two or more adjacent trees, and average 14 inches (35.6 cm) d.b.h. [47]. In New York leaf nests are built in deciduous trees and pines. Trees used for leaf nests ranged from 4 to 16 inches (10.2-40.6 cm) in diameter, were 15 to 70 feet (4.5-21.3 m) tall, and the nests were 12 to 60 feet (3.7-18.3 m) above the ground. Cavity trees ranged from 12 to 36 inches (30.5-91.4 cm) in diameter and were 20 to 60 feet (6-18.3 m) tall; entrance holes were 7 to 50 feet (2.1-15 m) above the ground [25]. Shelter: Nest cavities are sometimes used by one to several red squirrels in severe weather [25]. In winter red squirrels tunnel in deep snow to find food and escape severe weather [3,13]. Cone-bearing Trees and Food Cache Sites: Red squirrels in Arizona require 9 to 25 large, mature, cone-bearing trees (or a larger number of smaller cone-bearing trees) per territory [27,47]. Red squirrels use moist, shaded areas for the central food cache. These areas are created by groups of mature trees with some understory vegetation nearby. Large trees in a group closely spaced in 0.1 acre (0.04 ha) or less are favored. Canopy cover at 90 percent of cache sites is greater than 60 percent. One or more large snags, fallen logs, or live trees act as support structures for the cache [47]. In Pennsylvania primary red squirrel feeding sites (not caches) were associated with burrow entrances, overstory cone-bearing pines, and other primary feeding sites. They tended to be away from nest trees [50]. FOOD HABITS : Red squirrels consume conifer seeds, nuts, buds, sap, tender leaves, fruits, flowers, fungi, bird eggs, and small vertebrates [6]. In captive trials white spruce seed alone sustained red squirrels for at least 3 weeks. Red squirrels consumed seeds from an average of 144 cones per day per squirrel, probably more than they could consume in the wild. Red squirrels lost weight on black spruce seed alone, and preferred white spruce over black spruce seeds when presented with both [2,3]. In Arizona each red squirrel was estimated to consume the seeds of 42,000 to 131,000 pine cones per year [27,47]. On New Brunswick jack pine sites, red squirrels consumed at least 47 cones per day [7]. In summer a larger array of foods is eaten, including elm (Ulmus spp.) and maple (Acer spp.) seeds, raspberries (Rubus spp.) and other fruits, and green cones of pines, Douglas-fir, hemlock, cedar, and larch (Larix spp.). Some insects and nestling birds are also consumed [25]. In New Hampshire red squirrels were observed preying on the eggs and young of black-throated blue warblers (Dendroica caerulescens) [30]. Red squirrels lap sap from trees damaged by yellow-bellied sapsuckers (Sphyrapicus varius), and from other tree wounds [17]. They were also observed licking sap and dried sugar from sap wells drilled by red-naped sapsuckers (S. nuchalis) in Colorado [8]. In Vermont red squirrels were observed biting holes in hardwood trees at periods associated with sap flow. Sugar maple (Acer saccharum) was chosen more often than any other tree. Rather than licking sap immediately, the red squirrels left the fresh bite and returned at a later time, licking sap flows that had time to evaporate into more concentrated sugar syrup or dried sugar. Sugar spread by the researcher onto tree trunks did not immediately attract red squirrels; it was inferred that red squirrels returned intentionally to sap flows they had created [17]. The diet of the endangered Mount Graham red squirrel is not well known, but is assumed to be similar to that of other red squirrels; requirements include conifer seeds (mainly Engelmann spruce and subalpine fir) and mushrooms [28]. In western North America cones are cached by red squirrels in a large central location, often referred to as a midden (this type of food storage is known as larderhoarding). Middens also contain other foods such as seeds of other plant species, and mushrooms. Secondary middens are also developed, usually at the base of a tree or tree cavity, but are usually much smaller then the main midden [18,27]. Mushrooms are sometimes left in tree branches and cached after they have dried [13]. It was suggested that larderhoarding may be a response to intense predation in the winter; there is less movement involved in retrieving cones from a cache than in searching for cones all winter [7]. In Wyoming red squirrels spent most of their foraging time in whitebark pine forests finding and eating whitebark pine seed from cones or recovering dropped whitebark pine seed. Cone harvesting may begin as early as July 13 and cone caching usually begins by August 4. Red squirrels often leave cones on the ground below the tree for up to 3 days before caching them [18]. In Colorado red squirrels appear to prefer Douglas-fir cones over ponderosa pine cones; this may be a result of interspecific competition with Abert's squirrels which require ponderosa pine cones and bark [11]. In the Southwest commonly eaten and preferred seeds include those of Douglas-fir, blue spruce, Engelmann spruce, and white fir. Ponderosa pine seed is occasionally eaten in Arizona [31]. In eastern North America red squirrels in conifer-dominated forests have diets similar to those in western North America. In Maine red squirrels remove northern white-cedar (Thuja occidentalis) branchlets and cones in the fall, and consume branchlets with reproductive buds in the spring [4]. Winter foods include terminal buds of conifers, boxelder (Acer negundo) and red pine (Pinus resinosa) seeds, buds and sap of red maple (A. rubrum), gray birch (Betula populifolia) and sugar maple, corn (Zea mays), seeds of basswood (Tilia americana), sugar maple, silver maple (A. saccharinum), Norway maple (A. platanoides), northern red oak (Quercus rubra) and other oaks, hickory nuts, and butternuts (Juglans cinera). Eastern hemlock (Tsuga canadensis) cones are a staple item in some areas. Other winter foods include yellow-poplar (Liriodendron tulipifera) and sycamore (Platanus occidentalis) seeds, fruits of staghorn sumac (Rhus typhina) and smooth sumac (R. glabra), and bark. In April and May red squirrels consume tree buds and flowers, particularly those of American elm (Ulmus americana), sugar maple, silver maple, Norway maple, northern red oak, and butternut [13,25,32]. In New Brunswick red squirrels are scatterhoarders rather than larderhoarders; food is stored in small amounts in many places rather than in one central midden. Red squirrels stored cones from both serotinous and nonserotinous species: jack pine in central Ontario; black, white, and red spruce (Picea rubens) in New Brunswick; and black and red spruce in Maine. Cached cones are not sufficient for an entire winter food supply; however, jack pine cones remain closed for at least 1 year and are retained on the tree for up to 7 years and therefore provide a steady supply of winter food [7]. In Pennsylvania researchers could not locate cone caches in marginal red squirrel habitat dominated by aspens (Populus spp.). Red squirrels used a central location for consuming cones; these feeding areas have been identified by the remains of up to 103 cones [50]. PREDATORS : The main predators of red squirrels in Alberta are raptors, probably principally northern goshawk (Accipiter gentilis) [24]. Other red squirrel predators include red-tailed hawk (Buteo jamaicensis), red fox (Vulpes vulpes), bald eagle (Halieaatus leucocephalus), marten (Martes americana), lynx (Lynx lynx) and ermine (Mustela erminea) [13,44]. Lynx prey slightly more heavily on red squirrels in summer than winter (2% of lynx winter diet, 9% of summer diet) [13]. Red squirrels comprised 5.6 percent of 36 prey deliveries to northern goshawk nests and 17.5 percent of pellets (in 8 nests). More than 100 red squirrels were taken per season by a single pair of breeding northern goshawks [31]. In Yellowstone National Park martens use the subnivean zone to get to their prey which includes red squirrel. Red squirrels comprised 25 percent by volume of marten scats [37]. MANAGEMENT CONSIDERATIONS : Red squirrels are considered pests in some areas where they consume a large proportion of available conifer seeds. It has been suggested that they interfere with natural regeneration of conifers by removing most of the seed crop; this is particularly detrimental in years with poor cone crops [12,13,51]. Cached seed and cones do not usually germinate; a seed fungus (Caloscypha fulgens), which appears to prevent germination and rotting of seeds, is encouraged by the moist, cool conditions usually found in red squirrel cache sites [53,54]. In Newfoundland red squirrels are a recent introduction and have become a serious threat to black spruce cone harvests for commercial seed production [48]. Red squirrels clip (and often consume) terminal buds and peel the bark of trees, occasionally girdling stems. Gnawing damage to trees sometimes causes canker formation [13]. In Arizona red squirrels harvested more than 80 percent of limber pine (Pinus flexilis) cones before the cones opened (making the seeds unlikely to germinate even if they are not consumed); in open sites where red squirrels were absent more than 70 percent of cones opened on the trees [9]. In Newfoundland harvesting black spruce cones in August or September is recommended in order to anticipate removal of cones by red squirrels [48]. In central British Columbia thinning of 20-year-old lodgepole stands resulted in a reduction in red squirrel populations but did not appreciably lower the amount of tree damage inflicted by red squirrels gnawing on bark [41]. Red squirrels and other mycophagous species probably play an important role in the dispersal of the spores of mycorrhiza-forming fungi and therefore benefit conifer reproduction [26]. Red squirrel middens are a source of conifer seed for forestry in some western states [12,13]. Habitat Management: Red squirrels are dependent on mature conifers for food and cover. Conifer plantings in suburban areas tend to encourage red squirrels. Red squirrels will use nest boxes if they are placed in suitable habitat [13]. Vahle and Patton [27,47] recommended maintenance of areas with closely spaced groups of trees of different ages and sizes for red squirrel habitat. Conifers larger than 15 inches (38 cm) d.b.h. are necessary for cone production; at least three or four large trees per acre are needed. Timber harvest using group selection promotes habitats favored for red squirrel cache sites [47]. Reynolds and others [31] listed specific management recommendations for red squirrels in the Southwest in conjunction with maintenance of northern goshawk prey base. Black bears (Ursus americanus) damaged trees adjacent to Mount Graham red squirrel middens more often than at random locations. This damage frequently kills the tree. Death of the tree results in loss of cone production, but it also provides snags for nest cavities and storage sites [39]. The endangered grizzly bear (U. arctos horribilis) excavates red squirrel cone caches in whitebark pine stands; this is an important grizzly bear food source in some areas. Grizzly bear habitat management includes encouragement of both whitebark pine and red squirrel [56]. Red squirrels are economically important furbearers in Canada [19,53]. More red squirrels are taken but the total value is less than that of other furbearers [53]. Parasites and diseases of red squirrels were summarized by Layne [25] and Flyger and Gates [13].

FIRE EFFECTS AND USE

WILDLIFE SPECIES: Tamiasciurus hudsonicus
DIRECT FIRE EFFECTS ON ANIMALS : Most red squirrels probably escape most fires. In Minnesota oak savanna one red squirrel was found dead after a prescribed April fire that consumed all litter, killed most shrubs and young trees, and killed a few large trees [43]. HABITAT RELATED FIRE EFFECTS : Kirkpatrick and Mosby [20] suggested that prescribed fire in southern pine-hardwood sapling and older stages is unlikely to affect resident tree squirrels. This may apply to red squirrels, since important habitat includes mature trees unlikely to be adversely affected by low-severity fire. Fire severe enough to cause basal fire wounds may increase cavities available for food caches. Basal fire wounds are unlikely to increase cavities useful as nests for red squirrels [20]. In Yellowstone National Park lodgepole pine stands monitored for presence of birds and mammals during postfire succession, red squirrels were only present in stands with closed canopies [42]. In north-central Colorado red squirrels were not present on 8-year-old burned areas but were present in adjacent unburned lodgepole pine stands [33]. The maintenance of many mature coniferous forest types is often dependent on fire. Ponderosa pine, Douglas-fir, lodgepole pine, whitebark pine, and spruces are either dependent on stand-replacing fires for regeneration or on low-severity fires for maintenance. Even though severe fire is immediately destructive of red squirrel habitat, the long-term maintenance of most coniferous forests is dependent on fire [57]. FIRE USE : NO-ENTRY

REFERENCES

WILDLIFE SPECIES: Tamiasciurus hudsonicus
REFERENCES : 1. Bernard, Stephen R.; Brown, Kenneth F. 1977. Distribution of mammals, reptiles, and amphibians by BLM physiographic regions and A.W. Kuchler's associations for the eleven western states. Tech. Note 301. Denver, CO: U.S. Department of the Interior, Bureau of Land Management. 169 p. [434] 2. Brink, Charles Holden. 1964. Spruce seed as a food of the squirrels Tamiasciurus hudsonicus and Glaucomys sabrinus in interior Alaska. Fairbanks, AK: University of Alaska. 73 p. Thesis. [25160] 3. Brink, C. Holden; Dean, Frederick C. 1966. Spruce seed as a food of red squirrels and flying squirrels in interior Alaska. Journal of Wildlife Management. 30(3): 503-512. [13253] 4. Curtis, James D. 1946. Preliminary observations on northern white cedar in Maine. Ecology. 27: 23-36. [19804] 5. Davis, Donald Wayne. 1969. The behavior and population dynamics of the red squirrel (Tamiasciurus hudsonicus) in Saskatchewan. Fayetteville, AR: University of Arkansas. 229 p. Dissertation. In: Dissertation Abstracts. 30: 902 B. [Abstract]. [25261] 6. DeGraaf, Richard M.; Yamasaki, Mariko. 1986. New England wildlife: habitat, natural history, and distribution. Gen. Tech. Rep. NE-108. Broomall, PA: U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station. 491 p. [21386] 7. Dempsey, Jeffrey A.; Keppie, Daniel M. 1993. Foraging patterns of eastern red squirrels. Journal of Mammalogy. 74(4): 1007-1013. [22613] 8. Ehrlich, Paul R.; Daily, Gretchen C. 1988. Red-naped sapsuckers feeding at willows: possible keystone herbivores. American Birds. 42(3): 357-365. [14932] 9. Benkman, Craig W. 1982. Co-adaptations of red squirrels and Clark's nutcrackers with limber pine. Flagstaff, AZ: Northern Arizona University. 95 p. Thesis. [428] 10. Eyre, F. H., ed. 1980. Forest cover types of the United States and Canada. Washington, DC: Society of American Foresters. 148 p. [905] 11. Ferner, John W. 1974. Habitat relationships of Tamiasciurus hudsonicus and Sciurus aberti in the Rocky Mountains. Southwestern Naturalist. 18: 470-473. [25245] 12. Finley, Robert B., Jr. 1969. Cone caches and middens of Tamiasciurus in the Rocy Mountain region. University of Kansas Museum of Natural History. Misc. Publ. No. 51: 233-273. [25242] 13. Flyger, Vagn; Gates, J. Edward. 1982. Pine squirrels: Tamiasciurus hudsonicus and T. douglasii. In: Chapman, Joseph A.; Feldhamer, George A., eds. Wild mammals of North America: Biology, management, and economics. Baltimore, MD: The Johns Hopkins University Press: 230-238. [25232] 14. Garrison, George A.; Bjugstad, Ardell J.; Duncan, Don A.; [and others]. 1977. Vegetation and environmental features of forest and range ecosystems. Agric. Handb. 475. Washington, DC: U.S. Department of Agriculture, Forest Service. 68 p. [998] 15. Gurnell, John. 1984. Home range, territor., caching beh. & food supply of the red squirrel (Tamiasciurus hudsonicus fremonti) in a subalpine lodgepole pine forest. Animal Behaviour. 32(4): 1119-1131. [25358] 16. Hall, E. Raymond. 1981. The mammals of North America. 2nd ed. Vol. 2. New York: John Wiley and Sons. 1271 p. [14765] 17. Heinrich, Bernd. 1992. Maple sugaring by red squirrels. Journal of Mammalogy. 73(1): 51-54. [25246] 18. Hutchins, Harry E. 1994. Role of various animals in dispersal and establishment of whitebark pine in the Rocky Mountains, U.S.A. In: Schmidt, Wyman C.; Holtmeier, Friedrich-Karl, compilers. Proceedings--international workshop on subalpine stone pines and their environment: the status of our knowledge; 1992 September 5-11; St. Moritz, Switzerland. Gen. Tech. Rep. INT-GTR-309. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 163-171. [24638] 19. Kemp, Gerald A.; Keith, Lloyd B. 1970. Dynamics and regulation of red squirrel (Tamiasciurus hudsonicus) populations. Ecology. 51(5): 763-779. [25260] 20. Kirkpatrick, Roy L.; Mosby, Henry S. 1981. Effect of prescribed burning on tree squirrels. In: Wood, Gene W., ed. Prescribed fire and wildlife in southern forests: Proceedings of a symposium; 1981 April 6-8; Myrtle Beach, SC. Georgetown, SC: Clemson University, Belle W. Baruch Forest Science Institute: 99-101. [14815] 21. Klenner, Walt. 1991. Red squirrel population dynamics. II. Settlement patterns and the response to removals. Journal of Animal Ecology. 60: 979-993. [25247] 22. Klenner, Walt; Krebs, Charles J. 1991. Red squirrel population dynamics. I. The effect of supplemental food on demography. Journal of Animal Ecology. 60: 961-978. [25248] 23. Kuchler, A. W. 1964. Manual to accompany the map of potential vegetation of the conterminous United States. Special Publication No. 36. New York: American Geographical Society. 77 p. [1384] 24. Larsen, Karl W.; Boutin, Stan. 1994. Movements, survival, and settlement of red squirrel (Tamiasciurus hudsonicus) offspring. Ecology. 75(1): 214-223. [22744] 25. Shilts, Dean M. 1982. Fire management in Wind Cave National Park. In: Lotan, James E., ed. Fire--its field effects: Proceedings of the symposium; 1982 October 19-21; Jackson, WY. Missoula, MT: The Intermountain Fire Council: Pierre, SD: The Rocky Mountain Fire Council: 51-56. [10990] 26. Maser, Chris; Trappe, James M.; Ure, Douglas C. 1978. Implications of small mammal mycophagy to the management of western coniferous forests. Proceedings, 43rd North American Wildlife Conference: 78-88. [7174] 27. Patton, David R.; Vahle, J. Robert. 1986. Cache and nest characteristics of the red squirrel in an Arizona mixed-conifer forest. Western Journal of Applied Forestry. 1(2): 48-51. [25249] 28. Pereira, Jose M. C.; Itami, Robert M. 1991. GIS-based habitat modeling using logistic multiple regression: a study of the Mt. Graham red squirrel. Photogrammetric Engineering and Remote Sensing. 57(11): 1475-1486. [25250] 29. Price, Karen. 1994. Center-edge effect in red squirrels: evidence from playback experiments. Journal of Mammalogy. 75(2): 545-548. [25251] 30. Reitsma, Leonard R.; Holmes, Richard T.; Sherry, Thomas W. 1990. Effects of removal of red squirrels, Tamiasciurus hudsonicus, and eastern chipmunks, Tamias striatus, on nest predation in a n. hardwood forest: an artificial nest experiment. Okios. 57(3): 375-380. [25356] 31. Reynolds, Richard T.; Graham, Russell T.; Reiser, M. Hildegard; [and others]. 1992. Management recommendations for the northern goshawk in the southwestern United States. Gen. Tech. Rep. RM-217. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 90 p. [19721] 32. Riege, Dennis A. 1991. Habitat specialization and social factors in distribution of red and gray squirrels. Journal of Mammalogy. 72(1): 152-162. [25244] 33. Roppe, Jerry A.; Hein, Dale. 1978. Effects of fire on wildlife in a lodgepole pine forest. Southwestern Naturalist. 23(2): 279-287. [261] 34. Rusch, Doris A.; Reeder, William G. 1978. Population ecology of Alberta red squirrels. Ecology. 59(2): 400-420. [25252] 35. Scott, Virgil E.; Crouch, Glenn L. 1988. Summer birds and mammals of aspen-conifer forests in west-central Colorado. Res. Pap. RM-280. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 6 p. [13254] 36. Scott, Virgil E.; Crouch, Glenn L.; Whelan, Jill A. 1982. Responses of birds and small mammals to clearcutting in a subalpine forest in central Colorado. Res. Note RM-422. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 6 p. [4494] 37. Sherburne, Stuart S.; Bissonette, John A. 1993. Squirrel middens influence marten (Martes americana) use of subnivean access points. American Midland Naturalist. 129: 204-207. [25253] 38. Shiflet, Thomas N., ed. 1994. Rangeland cover types of the United States. Denver, CO: Society for Range Management. 152 p. [23362] 39. Smith, Andrew A.; Mannan, R. William; Davis, Russell. 1992. Black bear damage to old-growth trees around middens of Mount Graham red squirrels. In: Kaufmann, Merrill R.; Moir, W. H.; Bassett, Richard L., technical coordinators. Old-growth forests in the southwest and Rocky Mountain regions: Proceedings of a workshop; 1992 March 9-13; Portal, AZ. Gen. Tech. Rep. RM-213. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 179-183. [19053] 40. Sullivan, Thomas P. 1990. Responses of red squirrel (Tamiasciurus hudsonicus) populations to supplemental food. Journal of Mammalogy. 71(4): 579-590. [25254] 41. Sullivan, Thomas P.; Moses, Richard A. 1986. Red squirrel populations in natural and managed stands of lodgepole pine. Journal of Wildlife Management. 50(4): 595-601. [25255] 42. Taylor, Dale L. 1974. Biotic succession of lodgepole pine forests of fire origin in Yellowstone National Park. A report to the National Geographic Society. Paper on file with: U.S. Department of Agriculture, Forest Service, Intermountain Research Station, Fire Sciences Laboratory, Missoula, MT. 15 p. [16794] 43. Tester, John R. 1965. Effects of a controlled burn on small mammals in a Minnesota oak-savanna. American Midland Naturalist. 74(1): 240-244. [279] 44. Thompson, I. D.; Davidson, I. J.; O'Donnell, S.; Brazeau, F. 1989. Use of track transects to measure the relative occurrence of some boreal mammals in uncut forest and regeneration stands. Canadian Journal of Zoology. 67: 1816-1823. [25256] 45. U.S. Department of the Interior, Fish and Wildlife Service. 2013. Endangered Species Program, [Online]. Available: http://www.fws.gov/endangered/. [86564] 46. Uphoff, Karin C. 1990. Habitat use and reproductive ecology of red squirrels (Tamiasciurus hudsonicus) in central Arizona. Tempe, AZ: Arizona State University. 64 p. Thesis. [23989] 47. Vahle, J. Robert, Patton, David R. 1983. Red squirrel cover requirements in Arizona mixed conifer forests. Journal of Forestry. 81: 14-15, 22. [25259] 48. West, R. J. 1989. Cone depredations by the red squirrel in black spruce stands in Newfoundland: implications for commercial cone collection. Canadian Journal of Forest Research. 19: 1207-1210. [25243] 49. Williams, Charles E.; Johnson, W. Carter. 1992. Factors affecting recruitment of Pinus pungens in the southern Appalachian Mountains. Canadian Journal of Forest Research. 22: 878-887. [21670] 50. Yahner, Richard H. 1987. Feeding-site use by red squirrels, Tamiasciurus hudsonicus, in a marginal habitat in Pennsylvania. The Canadian-Field Naturalist. 101: 586-589. [25257] 51. Zasada, John C.; Van Cleve, Keith; Werner, Richard A.; [and others]. 1978. Forest biology and management in high-latitude North American forests. In: North American forests lands at latitudes north of 60 degrees: Proceedings of a symposium; 1977 September 19-22; Fairbanks, AK. [Place of publication unknown]: [Publisher unknown]: 137-195. On file at: U.S. Department of Agriculture, Forest Service, Intermountain Research Station, Fire Sciences Laboratory, Missoula, MT. [13613] 52. Smith, Christopher C. 1968. The adaptive nature of social organization in the genus of three squirrels Tamiasciurus. Ecological Monographs. 38(1): 31-63. [25258] 53. Obbard, Martyn E. 1987. Red squirrel. In: Novak, M.; Baker, J. A.; Obbard, M. E.; Mallock, A. M., eds. Wild furbearer management and conservation in North America. 264-281. [25262] 54. Sullivan, Thomas P.; Sutherland, Jack R.; Woods, T. A. D.; Sullivan, Druscilla S. 1984. Dissemination of the conifer seed fungus Caloscypha fulgens by small mammals. Canadian Journal of Forest Research. 14: 134-137. [25357] 55. The Network of Natural Heritage Programs and Conservation Data Centers and The Nature Conservancy. 1994. Element distribution - North America, vertebrates. Arlington, VA: The Nature Conservancy, Central Conservation Databases. 31 p. [23374] 56. Mattson, David J.; Reinhart, Daniel P. 1994. Bear use of whitebark pine seeds in North America. In: Schmidt, Wyman C.; Holtmeier, Friedrich-Karl, compilers. Proceedings--international workshop on subalpine stone pines and their environment: the status of our knowledge; 1992 September 5-11; St. Moritz, Switzerland. Gen. Tech. Rep. INT-GTR-309. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 212-220. [24645] 57. Kozlowski, T. T.; Ahlgren, C. E., eds. 1974. Fire and ecosystems. New York: Academic Press. 542 p. [1374]


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