Neotoma cinerea

Bushy-tailed Woodrats are highly territorial. A male will permit a female in his territory, but not another male. Both males and females mark their territories with a musky substance that can leave both scent and white color on rock ridges. The Woodrats make piles of vegetation and various collected items, and these materials can accumulate into middens of substantial size. The animals defecate and urinate on some of them, and those that bake in the sun can become rock-hard and last for tens of thousands of years. Paleobotanists using information from ancient middens have gained tremendous insight into the botanical history of the vast arid areas inhabited by woodrats.

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Bushy-tailed woodrats occur from the Yukon Territory and Northwest Territories south to Arizona and New Mexico and from California east to the Badlands of the upper Missouri River drainage area of South Dakota and Nebraska [29,73,111].

The specific ranges of the 13 subspecies are listed below [63]:

Neotoma c. acraia: east-central California to southeastern Idaho, Utah, and northern Arizona

Neotoma c. alticola: southern Washington, Oregon, southern Idaho, northeastern Caliifornia, and northern Nevada

Neotoma c. arizonae: Utah, Colorado, New Mexico, and Arizona

Neotoma c. cinerea: southeastern British Columbia, southern Alberta, and southwestern Saskatchewan south to central Idaho, western Wyoming, Montana, and western North Dakota

Neotoma c. cinnomomea: southwestern Wyoming, northeastern Utah, and northwestern Colorado

Neotoma c. drummondii: Yukon and Northwest Territories south to eastern British Columbia and western Alberta

Neotoma c. fusca: the Coast Ranges of Washington and Oregon

Neotoma c. lucida: southeastern California and southwestern Nevada

Neotoma c. macrodon: east-central Utah

Neotoma c. occidentalis: from Yukon Territory south to Washington, the Cascade Range of Oregon, and northern Idaho

Neotoma c. orolestes: southeastern Montana and southwestern South Dakota to northern New Mexico

Neotoma c. pulla: southwestern Oregon to northern California

Neotoma c. rupicola: southeastern Montana and North Dakota to western Nebraska and northeastern Colorado [63]

The following lists are speculative and are based on the habitat characteristics and species composition of communities bushy-tailed woodrats are known to occupy. There is not conclusive evidence that bushy-tailed woodrats occur in all the habitat types listed, and some community types, especially those used rarely, may have been omitted. See Preferred Habitat for more detail.

(key to state/province abbreviations)
UNITED STATES AZ CA CO ID MT NE NV NM ND OR SD UT WA WY
CANADA AB BC NT SK YK

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This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):

BLM PHYSIOGRAPHIC REGIONS [19]:

1 Northern Pacific Border

2 Cascade Mountains

3 Southern Pacific Border

4 Sierra Mountains

5 Columbia Plateau

6 Upper Basin and Range

7 Lower Basin and Range

8 Northern Rocky Mountains

9 Middle Rocky Mountains

10 Wyoming Basin

11 Southern Rocky Mountains

12 Colorado Plateau

13 Rocky Mountain Piedmont

14 Great Plains

15 Black Hills Uplift

16 Upper Missouri Basin and Broken Lands

Bushy-tailed woodrats occur from the Yukon Territory and Northwest Territories (Canada) south to Arizona and New Mexico and from California east to the Black Hills, South Dakota and the Badlands of the upper Missouri River drainage area of South Dakota and Nebraska in the United States.

Bushy-tailed woodrats are found in western North America, ranging from arctic Canada to northern New Mexico and Arizona. This species was thought to be restricted to higher elevations until very recently, when the first reports documenting Neotoma cinerea at elevations as low as 1200 m appeared. These findings lend support to molecular evidence which had earlier indicated that bushy-tailed woodrat populations were not isolated on mountain ranges throughout the Holocene. It is currently unclear whether these lowland populations are isolated by even lower valleys, or whether this species can exist in low, xeric areas as well. Bushy-tailed woodrats are currently found at elevations up to at least 3700 m. During the Pleistocene, N. cinerea is well-known at lower elevations, and its range extended south to southern Mexico. Up to thirteen subspecies are recognized. These subspecies are primarily defined based on geography and local ecology, and are not universally accepted.

(Escherich, 1981; Grayson and Livingston, 1989; Grayson et al., 1996; Mewaldt, 1982; Smith et al., 1995)

Biogeographic Regions: nearctic (Native )

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: Western North America, from southeastern Yukon and westernmost Northwest Territories southward through British Columbia and western Alberta to northern Arizona and New Mexico, east to the western Dakotas (Smith 1997). See Grayson and Livingston (1989) for a discussion of high-elevation records (3648 m and 4342 m).

Bushy-tailed woodrats are sexually dimorphic: adult males usually weigh 300-600 g with an average of 405 g, whereas adult females usually weigh only 250-350 g with an average of 270 g. These ranges are relatively large because this species occupies a large geographic range, and its body size is closely correlated with climate (conforms to Bergmann's rule). Neotoma cinerea is the largest and most cold-tolerant species of woodrat, and the largest and most sexually dimorphic individuals of this species are found in the northern parts of its range. In addition, body size of bushy-tailed woodrats (examined via fecal pellet size in middens) has been shown to correlate with known climatic fluctuations over the past 25,000 years. Woodrats are good climbers and have sharp claws. They have hypsodont molars with enamel ridges. The color of the pelage varies across the range, but is usually buff with white areas around the feet. The bushy tail characteristic of the species is used to warm the animal. Pictures of bushy-tailed woodrats are available in Vaughan (1990), Escherich (1981), and on the web at: . Escherich (1981) provides pictures of both sexes at various point throughout ontogeny, as well as pictures of skulls and skins.

(Egoscue, 1962; Escherich, 1981; Finley, 1990; Hickling et al., 1991; Martin, 1973; Smith, 1995; Smith et al., 1995; Vaughan, 1990)

Average mass: 335.5 g.

Average basal metabolic rate: 1.152 W.

Length: 47 cm

Weight: 444 grams

Length:
Average: 379 mm males; 356 mm females
Range: 310-470 mm males; 272-410 mm females

Weight:
Average: 337 g males; 275 g females
Range: 181-585 g males; 166-370 g females

More info for the term: tree

Den sites are primary limiting factors of bushy-tailed woodrat habitat [29,47,111]. Depending on the subspecies of bushy-tailed woodrat, dens may be located in openings between rocks, coarse woody debris (snags and logs), or dwarf mistletoe brooms [29]. In areas with heavy snowfall, rock shelters are the most important resource for the bushy-tailed woodrat [47]. In areas with mild climates and low availability of rock shelters, coarse woody debris, mistletoe brooms, and rock crevices along streams are utilized more often [21,26,35,66,77,82,85,94,96,124].

Bushy-tailed woodrat shelter consists of 2 parts, the den and the nest [29,47]. Dens refer to a shelter constructed from items such as sticks [47], leaves, grass, bark, feathers, paper, small stones [114] and human artifacts [16]. Dens are important for protection against predators and are almost never constructed in the open without a bush, rock crevice, or tree for support [47]. They are used as eating platforms, a platform for the nest, and a drying area for food [16]. Within the den are tunnels, chambers, and passages. One of the chambers may contain 2 or more nests, and other chambers are used for food storage and feeding. A lifetime may be spent using the same den [114].

Nests refer to a small cup-like structure usually located inside the den. Occasionally a nest may be found without a den [47]. On the Oregon coast and Coast Ranges, bushy-tailed woodrats may construct nests in trees up to 50 feet (15 m) above ground [29,85]. Nests are 6 to 8 inches (15-20 cm) in diameter [85] and are constructed of fibrous shredded vegetation [16,51,85].

More info for the terms: climax, cover, density, frequency, presence, succession, tree

Bushy-tailed woodrats are the most boreal species within the Neotoma genus [47,51]. They inhabit areas from sea level to 14,110 feet (4,300 m) and are most often associated with montane habitats [47,61,114]. Bushy-tailed woodrats are arboreal rodents [13,21,26,29,30,47], associating primarily with ponderosa pine, Douglas-fir, spruce (Abies spp.), and quaking aspen (Populus tremuloides) forests [47,51,85]. Other common habitat types inhabited by the bushy-tailed woodrat include pinyon (Pinus spp.)-juniper (Juniperusspp.) woodlands [5,22,44,50,56,67,78,93,110,125] and big sagebrush habitat [5,45,49,58,72,89,125].

Occurrence of bushy-tailed woodrats is closely tied to the geology of a landscape [47]. Shelter and topography are important determinants of habitat suitability [47,51]. The availability of rock shelters may be a more important resource for the bushy-tailed woodrat than the associated plant community [34,47,51]. Preferred habitat varies depending on the subspecies of bushy-tailed woodrat; however, most subspecies are associated with rocky environments such as talus slopes [16,51,116], rockslides [47,114], boulder fields [34], rock outcrops [16,34,51,85,116], cliffs [51,116], and caves [16,51,61,106,114,116].

Due to the occasional scarcity of rocky habitats in the Pacific Northwest, hollow trees, logs, dwarf mistletoe (Arceuthobium spp.) brooms, and coarse woody debris are used for denning, foraging, and shelter [21,26,34,35,66,77,82,85,94,96,124]. In the Columbia River Basin, bushy-tailed woodrats use grand fir and white fir snags most often for den sites [77,94]. Tree cavities created by the pileated woodpecker (Dryocopus pileatus) are used by bushy-tailed woodrats in grand fir, western larch, and ponderosa pine trees [21,24,25,26].

Bushy-tailed woodrats may also associate with streamside habitats [29,34,47,82,87]. In southwestern Oregon, streamside forests provide the most suitable habitat for bushy-tailed woodrat [29]. In wet Douglas-fir and western hemlock (Tsuga heterophylla) forests in western Washington, bushy-tailed woodrats are found primarily in rocky, streamside areas [82]. Riparian quaking aspen woodlands in rangeland communities are commonly used by bushy-tailed woodrats in northeastern Nevada [87].

Human-made buildings [40,51,85,112,114] and mine tunnels are sometimes used by bushy-tailed woodrat [51].

Stand- and landscape-level habitat: Bushy-tailed woodrats may be found in early through climax stages of succession [4,29,34,82,125].

In the Pacific Northwest, one of the preferred landscapes for the bushy-tailed woodrat is closed pole-sapling stands, which are somewhat ephemeral as they succeed to small saw-log stands. Extensive areas of Douglas-fir old-growth (>200 years) may be most suitable for maintaining a viable population of bushy-tailed woodrats. Contiguous areas of suitable habitat or corridors connecting suitable habitat are also important [29].

In western Oregon and western Washington, bushy-tailed woodrats preferred mature (>80 years), unmanaged upland Douglas-fir-western hemlock streamside forests more than young (35 to 80 years), "managed" streamside forest. Streams in this habitat were narrow, deeply cut, and associated with forested boulder fields. The adjacency of streams was not sufficient to ensure occupancy by bushy-tailed woodrats.

Percent frequency of occurrence of bushy-tailed woodrats in Douglas-fir/western hemlock streamside forests [34]  

Stream present

Stream not present

  Stands (n) % occupied Stands (n) % occupied Mature, unmanaged forest 27 78 34 21 Young, managed forest 12 33 46 17

In the Pacific Northwest, Douglas-fir forests can be "sources" or "sinks" for the bushy-tailed woodrat, depending on the stand condition, presence of streams, and occurrence of predators such as the northern spotted owl (Strix occidentalis caurina) [29]. "Sources" are defined as an environment capable of sustaining a viable population. "Sinks" are defined as an environment capable of maintaining a population for a short time, but supporting low reproduction or periods of unsuitability for occupancy.

Habitat ratings for stand conditions in Douglas-fir forests in the Pacific Northwest [29] Closed sapling-pole
(20 years old; average DBH=1 to 21 inches (3-53 cm); canopy cover >60%) Source and sink Small sawtimber
(60 years old, DBH and canopy cover not given) Sink Large sawtimber
(100 years old; average DBH=21 inches (53 cm); canopy cover <100%; decay and decadence lacking) Sink Old-growth
(Stand 700 years old, at least 2 tree layers, decay in living trees, snags, fallen trees) Source and sink

Information on landscape suitability for the bushy-tailed woodrat is sparse outside the Pacific Northwest. In Douglas-fir and mixed-conifer forests in southwestern Oregon and northern California, bushy-tailed woodrats were found in young and mature forests containing diverse understory vegetation [86]. Bushy-tailed woodrats were transients or ephemeral residents within the quaking aspen seral stage of a forest dominated by Engelmann spruce (Picea engelmannii) in the Wasatch Mountains in Utah [4]. In Montana, bushy-tailed woodrats are found in old-growth western larch (Larix occidentalis)/Douglas-fir forests [65]. In alluvial valleys of the Green and Yampa rivers in northwestern Colorado and northeastern Utah, bushy-tailed woodrat presence was examined in 3 habitats: high floodplain, low floodplain, and upland. Bushy-tailed woodrats were found in high floodplain and upland habitats, but the numbers in upland habitats were small. In high floodplain habitat, flooding occurred at longer intervals than in low floodplain areas, which flooded every other spring. High floodplain habitat contained the most mature cottonwood (Populus fremontii) and woody debris of the 3 habitats studied. In upland habitat, where flooding never occurred, dominant vegetation included sagebrush (Artemisia spp.), greasewood (Sarcobatus spp.), and saltbush (Atriplex spp.) [49].

Home range and density: Bushy-tailed woodrats have a larger home range than any other Neotoma species. This may due to the requirement of existing geologic structures for den sites, such as fissures in rocky outcrops. Denning and nesting sites are usually limiting resources in bushy-tailed woodrat habitat. This may lead to concentrations of bushy-tailed woodrats in certain areas [47]. Importance of a suitable den site may outweigh the costs of maintaining a large home range [47].

Bushy-tailed woodrats occur in small, widely separated family groups [29]. The minimum habitat size needed per family group has been estimated at 80 acres (32 ha) [29]. It is rare to find more than one family group on a talus slope covering 2 to 5 acres (0.8-2.0 ha). Banfield [16] reported an average population density of 1 bushy-tailed woodrat per 20 acres (8 ha) in Canada. Bushy-tailed woodrats may forage up to 450 feet (137 m) from the den; this constitutes a 15 acre (6 ha) home range [29]. In southwestern Oregon, Carey [29] recorded movements of up to 1,250 feet (381 m) within trapping grids that were only 1,300 feet (396 m) wide, which suggests a maximum home range of about 110 acres (45 ha). The average maximum distance moved per individual was 280 feet (85.3 m).

The size of the home range is positively correlated with the number of females in the group [47]. Male bushy-tailed woodrats have larger home ranges than females [29]. In the Kananaskis Valley in southwestern Alberta, average home range size for male bushy-tailed woodrats was 6.12 ha (n=23, range 1.6 to 11.2 ha), and for females was 3.56 ha (n=27, range 0.1 to 10.4 ha) [116].

In mixed-conifer (grand fir and Douglas-fir) habitat in southwestern Oregon, bushy-tailed woodrat density was greatest (1.08 individuals/ha ± 0.51 (SE)) in streamside closed-canopy habitat. In Douglas-fir forests, bushy-tailed woodrat density was greatest (0.59 individuals/ha ± 0.57 (SE)) in rocky sites. For more details about bushy-tailed woodrat density in different habitat types in Oregon, see Carey and others [32].

In addition to the plant communities listed above, occurrence of the bushy-tailed woodrat was noted in the following habitats:

Bushy-tailed woodrats were found inhabiting rock outcrops surrounded by big sagebrush (Artemisia tridentata)/cheatgrass (Bromus tectorum), big sagebrush/Sandberg bluegrass (Poa secunda), and big sagebrush/needle-and-thread (Stipa comata) community types at the Hanford Site in Washington [58].

In the Slim Buttes area of northwestern South Dakota, bushy-tailed woodrats occur in green ash (Fraxinus pennsylvanica)/chokecherry (Prunus virginianus) habitat [109].

At Bass Lake, California, 1 bushy-tailed woodrat was found in a forest dominated by incense-cedar (Calocedrus decurrens), white fir (Abies concolor), California black oak (Quercus kelloggii), ponderosa pine (Pinus ponderosa), sugar pine (Pinus lambertiana), and white alder (Alnus rhombifolia). In Lake Tahoe, California, bushy-tailed woodrats were found inhabiting a building surrounded by Jeffrey pine (Pinus jeffreyi), sugar pine, lodgepole pine (Pinus contorta), incense-cedar, white fir, western juniper (Juniperus occidentalis), California black oak, and chaparral. Chaparral consisted of greenleaf manzanita(Arctostaphylos patula), huckleberry oak (Quercus vaccinifolia), whitethorn ceanothus (Ceanothus cordulatus), bush chinquapin (Castanopsis semperivirens), bitter cherry (Prunus emarginata), big sagebrush, and other species [112].

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This species is known to occur in association with the following Rangeland Cover Types (as classified by the Society for Range Management, SRM):

More info for the term: cover

SRM (RANGELAND) COVER TYPES [108]:

101 Bluebunch wheatgrass

102 Idaho fescue

107 Western juniper/big sagebrush/bluebunch wheatgrass

108 Alpine Idaho fescue

109 Ponderosa pine shrubland

110 Ponderosa pine-grassland

202 Coast live oak woodland

203 Riparian woodland

207 Scrub oak mixed chaparral

208 Ceanothus mixed chaparral

209 Montane shrubland

210 Bitterbrush

213 Alpine grassland

216 Montane meadows

302 Bluebunch wheatgrass-Sandberg bluegrass

304 Idaho fescue-bluebunch wheatgrass

314 Big sagebrush-bluebunch wheatgrass

315 Big sagebrush-Idaho fescue

401 Basin big sagebrush

402 Mountain big sagebrush

403 Wyoming big sagebrush

406 Low sagebrush

408 Other sagebrush types

409 Tall forb

410 Alpine rangeland

411 Aspen woodland

412 Juniper-pinyon woodland

415 Curlleaf mountain-mahogany

422 Riparian

501 Saltbush-greasewood

503 Arizona chaparral

504 Juniper-pinyon pine woodland

612 Sagebrush-grass

614 Crested wheatgrass

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This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):

More info for the term: cover

SAF COVER TYPES [48]:

12 Black spruce

16 Aspen

63 Cottonwood

107 White spruce

201 White spruce

204 Black spruce

205 Mountain hemlock

206 Engelmann spruce-subalpine fir

207 Red 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

217 Aspen

218 Lodgepole pine

220 Rocky Mountain juniper

221 Red alder

222 Black cottonwood-willow

223 Sitka spruce

224 Western hemlock

225 Western hemlock-Sitka spruce

226 Coastal true fir-hemlock

227 Western redcedar-western hemlock

228 Western redcedar

229 Pacific Douglas-fir

230 Douglas-fir-western hemlock

231 Port-Orford-cedar

232 Redwood

234 Douglas-fir-tanoak-Pacific madrone

235 Cottonwood-willow

237 Interior ponderosa pine

238 Western juniper

239 Pinyon-juniper

243 Sierra Nevada mixed conifer

244 Pacific ponderosa pine-Douglas-fir

245 Pacific ponderosa pine

246 California black oak

247 Jeffrey pine

248 Knobcone pine

253 Black spruce-white spruce

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This species is known to occur in association with the following plant community types (as classified by Küchler 1964):

More info for the term: shrub

KUCHLER [79] PLANT ASSOCIATIONS:

K001 Spruce-cedar-hemlock forest

K002 Cedar-hemlock-Douglas-fir forest

K003 Silver fir-Douglas-fir forest

K004 Fir-hemlock forest

K005 Mixed conifer forest

K006 Redwood forest

K007 Red fir forest

K008 Lodgepole pine-subalpine forest

K010 Ponderosa shrub 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

K023 Juniper-pinyon woodland

K024 Juniper steppe woodland

K025 Alder-ash forest

K026 Oregon oakwoods

K028 Mosaic of K002 and K026

K029 California mixed evergreen forest

K030 California oakwoods

K033 Chaparral

K034 Montane chaparral

K037 Mountain-mahogany-oak scrub

K038 Great Basin sagebrush

K040 Saltbush-greasewood

K050 Fescue-wheatgrass

K051 Wheatgrass-bluegrass

K052 Alpine meadows and barren

K055 Sagebrush steppe

K056 Wheatgrass-needlegrass shrubsteppe

K063 Foothills prairie

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This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):

ECOSYSTEMS [57]:

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 

FRES27 Redwood 

FRES28 Western hardwoods 

FRES29 Sagebrush 

FRES30 Desert shrub 

FRES34 Chaparral-mountain shrub 

FRES35 Pinyon-juniper 

FRES36 Mountain grasslands 

FRES37 Mountain meadows 

FRES39 Prairie 

FRES41 Wet grasslands 

FRES44 Alpine  

Habitat and Ecology

Systems

• Terrestrial

Bushy-tailed woodrats occupy a range of habitats from boreal woodlands to deserts. They are cliff-dwellers, and are often found on isolated, high-elevation bouldery exposures under a variety of temperature and moisture regimes. They require adequate shelter inside the rocks, though they are occasionally found inhabiting abandoned buildings as well.

(Frase and Sera, 1993; Grayson and Livingston, 1989; Topping and Millar, 1996; Vaughan, 1990)

Terrestrial Biomes: taiga ; desert or dune ; savanna or grassland ; chaparral ; forest ; mountains

Comments: Alpine to Sonoran life zones. Inhabits mountains, cliffs, talus slopes, caves, and rock outcrops, both in forests and open deserts; also in deserted buildings and mine shafts. Young are born in nest within den built of sticks among rocks or in old building or mine shaft.

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

More info for the terms: competition, forbs, shrubs

Bushy-tailed woodrats are herbivores [4,67,114] with a broad, flexible diet [47,55,85]. Regional specialization on certain locally abundant food items may occur [47,51]. Due to their flexible diet, food availability is likely not a limiting factor in habitats occupied by bushy-tailed woodrats. Generally, food is a more abundant resource than shelter [47]. In general, bushy-tailed woodrats do not travel far from their den to forage [55,116]. In Gunnison County, Colorado, bushy-tailed woodrats satisfied their foraging needs within a 98 foot (30 m) radius of their dens, but would occasionally travel upto 500 feet (152 m) from their den for unknown reasons [55]. Food is dried on rocks before storage [16,47,51], and is stored extensively in middens located at the periphery of the den in late August and September [16,47,51]. As plant diversity increases in bushy-tailed woodrat habitat, diversity of midden contents increases [55]. Middens may be several feet deep [51] and have been radiocarbon dated to be thousands of years old [122].

Foods eaten include cones and needles of coniferous trees [85,114], berries, leaves [47], shrubs [16,72], and forbs [67]. Fungi are a major food item in lodgepole pine and grand fir habitats in northeast Oregon. Bushy-tailed woodrats are vectors of spore dissemination of hypogeous mycorrhizal fungi in conifer forests [86].

In Canada, bushy-tailed woodrats showed a preference for the leaves of quaking aspen, cherry (Prunus spp.), rose (Rosa spp.), snowberry (Symphoricarpos spp.), currants (Ribes spp.), elderberries (Sambucus spp.), and willows (Salix spp.). The twigs and needles of western white pine (Pinus monticola), Douglas-fir, Engelmann spruce (Picea engelmannii), subalpine fir (Abies lasiocarpa), and juniper (Juniperus spp.), and the seeds and/or fruits of Douglas-fir, anemone (Anemone spp.), fireweed (Epilobium angustifolium), gentian (Gentianella spp.), honeysuckle (Lonicera spp.), cinquefoil (Potentilla spp.), gooseberry (Ribes spp.), raspberry (Rubus spp.), and elderberry were also eaten [16].

Consumption of woody vegetation by bushy-tailed woodrats may decrease competition for food with other forb-eating small mammals. In a pinyon-juniper habitat in the Piceance Basin in Colorado, 75% of the bushy-tailed woodrat diet was composed of woody plants, primarily antelope bitterbrush (Purshia tridentata). Forbs composed 15% of their diet, but the percentage of forbs in the diet may increase in years of heavy rainfall. For a list of foods eaten by bushy-tailed woodrat in pinyon-juniper habitat in Colorado, see Haufler and Nagy [67]. In basin big sagebrush (Artemisia tridentata ssp. tridentata) habitat in south-central Idaho, plains prickly-pear (Opuntia polyacantha) was the main food eaten by bushy-tailed woodrats [72].

Because this species occupies such a wide range of habitats, its diet is variable. However, N. cinerea may best be described as a generalist herbivore. Most authors have considered it entirely herbivorous, though Johnson and Hansen (1979) believed a small component of its diet consists of arthropods. Bushy-tailed woodrats eat lots of woody vegetation, and in drier habitats also concentrate on succulents. This species gets all of its water from its food and does not need to drink. Woodrats tend to eat plant materials which have high concentrations of defensive chemicals; they combat these defenses by eating only small amounts of each species. Neotoma cinerea also tends to eat low-energy food items and plants which are high in oxalates. This has implications for the building of middens, discussed below. Neotoma cinerea has an enlarged caecum, and engages in coprophagy. Johnson and Hansen (1979) provide a list of specific food items utilized by this species in a cool, dry environment in Idaho.

(Escherich, 1981; Frase and Sera, 1993; Haufler and Nagy, 1984; Johnson and Hansen, 1979; Vaughan, 1990)

Comments: Feeds on a variety of vegetation; twigs, shoots, leaves, needles, fruit, and seeds. May store food.

More info for the terms: fitness, frequency, presence, relative frequency

Bushy-tailed woodrats add substantially to the prey base of birds and mammals [29,34]. Their presence and abundance may affect the fitness of spotted owls (Strix occidentalis) throughout their range [29,32,34,92,117,118,123], but their importance varies locally [32]. Bushy-tailed woodrats comprised >10% relative frequency and total biomass of the Mexican spotted owl's (Strix occidentalis lucida) diet in the northern portion of its range [123]. In the Olympic Peninsula, Coast Range, Umpqua River Valley, and Klamath Mountains of Oregon, bushy-tailed woodrats comprised 2% to 70% of prey biomass for the northern spotted owl [32].

Other predators of bushy-tailed woodrats include the great-horned owl (Bubo virginianus) [16,29,78], boreal owl (Aegolius funereus) [68], American marten (Martes americana) [16,23,29], fisher (Martes pennanti) [130], and bobcat (Lynx rufus) [29].

Incidental predators include the coyote (Canis latrans) [29,45], western spotted skunk (Spilogale putorius), long-tailed weasel (Mustela frenata) [29], red-tailed hawk (Buteo jamaicensis), northern goshawk (Accipiter gentilis) [47], rattlesnake (Viperidae), wolverine (Gulo gulo) and fox (Vulpes spp. and Urocyon spp.) [16].

Due to the large amount of time spent in dens, bushy-tailed woodrats are particularly susceptible to ectoparasites such as ticks, chiggers, lice, mites, fleas, cone-nosed bugs, and warble flies [51].

More info for the terms: climax, cover, fire severity, fuel, high-severity fire, mixed-severity fire, prescribed fire, presence, severity, shrubs, source habitat, succession, wildfire

Fire may influence bushy-tailed woodrat populations by altering habitat structure and/or plant community composition [83]. The rapidity of recolonization of a disturbed area by small mammals depends on the size and severity of the disturbance and the presence of refugia [74].

As of this writing, no information is available on the HABITAT RELATED FIRE EFFECTS on the bushy-tailed woodrat. Despite the lack of information, some generalizations based on their habitat requirements may be possible. Coarse woody debris and mistletoe brooms are important resources for the bushy-tailed woodrat, primarily in the Pacific Northwest [21,26,34,35,39,82,85,94,96,124] (see Preferred Habitat). Conflicts in coarse woody debris management have arisen between retaining logs for wildlife use and lowering fuel levels to decrease the risk of wildfire [24]. Coarse woody debris and mistletoe brooms close to the ground torch easily and would probably be consumed by low-severity prescribed fire [69]. In ponderosa pine and dry Douglas-fir habitats, low-severity, high-frequency FIRE REGIMES will likely reduce bushy-tailed woodrat populations unless fire prescriptions mitigate the loss of coarse woody debris and mistletoe brooms [82]. In 12 vegetation types in coastal and interior British Columbia, wildlife community structure was highly correlated with FIRE REGIMES. As fire size and intensity increased, the proportion of species using woody cavities decreased due to the loss of snags and woody debris. As the interval between fires increased and downed woody debris accumulated, proportions of species using downed wood increased [27].

Bushy-tailed woodrats are found in early successional through climax stages of succession [4,29,34,125], and their presence depends more on cover and food availability than on the seral stage [47,51]. In the spruce-fir zone of northern Utah, for example, bushy-tailed woodrats were found in meadows and quaking aspen stands. These communities are commonly the first successional stages after fire [103]. In the Sierra Nevada, bushy-tailed woodrats often inhabit early postfire successional stages of Jeffrey pine and lodgepole pine communities [20,76]. Some berry-producing shrubs that provide food for bushy-tailed woodrats, such as blackberries, raspberries, and gooseberries, often thrive after fire [127]. However, severe, stand-destroying fires that consume the organic layer can kill the roots of many berry-producing shrubs, reducing the potential for sprouting and delaying revegetation [97,119]. According to Lehmkuhl and others [82], unmanaged mature forests are source habitat for bushy-tailed woodrats compared to thinned and/or burned forest stands. Closed-sapling pole habitats are also source habitat for bushy-tailed woodrats (see Stand- and landscape-level habitat) [29].

In eastern Washington and Oregon, wildlife appears to be well-adapted to mixed-severity FIRE REGIMES in mixed-conifer forests [81]. A critical habitat feature affecting wildlife habitat in mixed-severity FIRE REGIMES is the mosaic of vegetation conditions that are created [2]. Mixed-severity fires in dry forest types create mosaics of varying burn intensity and a complex of open and closed-canopy forest structure containing woody debris, snags, and understory vegetation [3,81]. Woody debris may be abundant in mixed-severity vegetation types, but availability varies over time. Consumption of woody debris on the forest floor is offset by the creation of snags in patches burned at moderate and high severities [3]. Burning to create patchy fire severity may therefore benefit the bushy-tailed woodrat [82].

Snags with large cavities are important for many species of birds and mammals including the bushy-tailed woodrat [21]. A bushy-tailed woodrat nest was found in an old-growth log with a fire scar opening 3 feet (0.9 m) high and 2 feet (0.6 m) wide [29]. Old pileated woodpecker cavities used by bushy-tailed woodrats may be at risk of destruction by high-severity fire [82]; however, high-severity fire may also create snags [26].

To reduce slash from logging operations while maintaining coarse woody debris, broadcast burning may be useful. Because of the time of year that broadcast burning is conducted, large diameter materials are usually not consumed [98,99,101]. In addition to broadcast burning, slash <6 inches (15 cm) diameter can be piled and burned to reduce fine fuels while maintaining coarse woody debris [96]. Prescribed fire has less impact on small mammals in western larch habitat than mechanical scarification [104], which destroys small mammal habitat [84].

The following table provides fire-return intervals for plant communities and ecosystems where bushy-tailed woodrats may occur. For further information, see the FEIS review of the dominant plant species listed below.

Community or Ecosystem Dominant Species Fire Return Interval Range (years) silver fir-Douglas-fir Abies amabilis-Pseudotsuga menziesii var. menziesii >200 grand fir Abies grandis 35-200 [8] California chaparral Adenostoma and/or Arctostaphylos spp. <35 to <100 sagebrush steppe Artemisia tridentata/Pseudoroegneria spicata 20-70 [95] basin big sagebrush Artemisia tridentata var. tridentata 12-43 [102] mountain big sagebrush Artemisia tridentata var. vaseyana 15-40 [10,28,90] Wyoming big sagebrush Artemisia tridentata var. wyomingensis 10-70 (x=40) [120,129] saltbush-greasewood Atriplex confertifolia-Sarcobatus vermiculatus 95] curlleaf mountain-mahogany* Cercocarpus ledifolius 13-1,000 [12,105] California montane chaparral Ceanothus and/or Arctostaphylos spp. 50-100 California steppe Festuca-Danthonia spp. 95] green ash Fraxinus pennsylvanica <35 to >300 [46,121] western juniper Juniperus occidentalis 20-70 Rocky Mountain juniper Juniperus scopulorum <35 [95] western larch Larix occidentalis 25-350 [9,18,38] Engelmann spruce-subalpine fir Picea engelmannii-Abies lasiocarpa 35 to >200 [8] black spruce Picea mariana 35-200 [43] blue spruce* Picea pungens 35-200 [8] pinyon-juniper Pinus-Juniperus spp. <35 [95] Rocky Mountain bristlecone pine P. aristata 9-55 [41,42] whitebark pine* Pinus albicaulis 50-200 [1,6] Rocky Mountain lodgepole pine* Pinus contorta var. latifolia 25-340 [17,18,115] Sierra lodgepole pine* Pinus contorta var. murrayana 35-200 [8] Colorado pinyon Pinus edulis 10-400+ [53,59,75,95] Jeffrey pine Pinus jeffreyi 5-30 western white pine* Pinus monticola 50-200 Pacific ponderosa pine* Pinus ponderosa var. ponderosa 1-47 [8] interior ponderosa pine* Pinus ponderosa var. scopulorum 2-30 [8,14,80] Arizona pine Pinus ponderosa var. arizonica 2-15 [14,37,107] aspen-birch Populus tremuloides-Betula papyrifera 35-200 [43,121] quaking aspen (west of the Great Plains) Populus tremuloides 7-120 [8,62,88] mountain grasslands Pseudoroegneria spicata 3-40 (x=10) [7,8] Rocky Mountain Douglas-fir* Pseudotsuga menziesii var. glauca 25-100 [8,10,11] coastal Douglas-fir* Pseudotsuga menziesii var. menziesii 40-240 [8,91,100] Pacific coast mixed evergreen Pseudotsuga menziesii var. menziesii-Lithocarpus densiflorus-Arbutus menziesii <35-130 [8,36] California oakwoods Quercus spp. <35 [8] California black oak Quercus kelloggii 5-30 [95] redwood Sequoia sempervirens 5-200 [8,52,113] western redcedar-western hemlock Thuja plicata-Tsuga heterophylla >200 western hemlock-Sitka spruce Tsuga heterophylla-Picea sitchensis >200 mountain hemlock* Tsuga mertensiana 35 to >200 [8] *fire return interval varies widely; trends in variation are noted in the species review

More info for the term: prescribed fire

Bushy-tailed woodrats can probably escape most fires by taking refuge in rocky habitats. A study in California showed that during a prescribed fire, woodrats (Neotoma spp.) evaded harm by escaping to rock outcrops [70]. Woodrats that do not escape to these refugia may be killed by fire [128]. Bushy-tailed woodrats residing in riparian areas are probably protected by their habitat, which may burn infrequently and in a patchy pattern.

More info for the terms: altricial, cover, litter, philopatric

Mating: Female bushy-tailed woodrats are seasonally polyoestrous [16,47,51]. The breeding period occurs from January to August [16,34,85] and peaks between March and June [16]. In southwestern Oregon, 55% (n not given) of female bushy-tailed woodrats were found lactating until fall, indicating a longer breeding period [29].

Social Organization: Bushy-tailed woodrats occur in small family groups, which are often widely separated, and distribution is often patchy [29,47]. Males are territorial and aggressively defend dens and foraging areas [16,29,47]. Bushy-tailed woodrats are considered polygynous by some authors [16,29,47]; however, this is not based on observed matings, but on the size and relative overlap of male and female ranges [34].

Gestation period and litter size: Gestation of bushy-tailed woodrats is 27 to 32 days [16,47]. On the Oregon Coast, young are born in March [85]. Litter size ranges from 1 to 6 [47,85,114], and averages 3.5 [16]. In the Sierra Nevada, mean litter size was 2.5 (n=11) [47]. Number of litters is typically 1 per year, especially in northern parts of the bushy-tailed woodrat's range [16]. In southern parts of the bushy-tailed woodrat's range, 2 litters may be produced [85].

Development: Young bushy-tailed woodrats are altricial [16,85], and the male parent does not help raise offspring [47]. Young are weaned between 26 and 30 days of age [16], and dispersal from the nest occurs at 2 months of age [114]. Bushy-tailed woodrats reach sexual maturity at 11 months [16], and breeding begins during spring and summer, ~1 year following birth [47].

Dispersal: Female bushy-tailed woodrats are generally philopatric and breed on the same rock outcrop over successive years. Male yearlings are more mobile than female yearlings and may disperse greater distances in search of suitable habitat and den sites [47]. Dispersal distances of 1.4 to 2.0 miles (2.2-3.2 km) have been recorded [29]. Once a territory is established, both sexes are relatively sedentary. The separation of family groups may attract predators and lead to extinction of the colony via emigration, predation, and random demographic processes such as death and low birth rates. Therefore, dispersal of offspring is important in the recolonization of vacated habitats [29,47].

Habits: Bushy-tailed woodrats are primarily nocturnal and are most active during the half hour after sunset and at dawn, year-round [16,29,47,51,85,114,118].

Survival: Litters produced early in the season have a greater chance of survival than litters produced later in the season [47]. Bushy-tailed woodrats may live 3 to 4 years [47,114].

Annual survival rates for bushy-tailed woodrats in dry forest cover types in the Cascade Range [82]

  Year

Cover type

1997-1998 1998-1999 1999-2000 Open ponderosa pine 0.14 0.13 0.05 Young mixed conifer
(grand fir (Abies grandis), Douglas-fir (Pseudotsuga menziesii), and ponderosa pine) 0.25 0.17 0.05 Mature mixed conifer (same species as above) 0.08 0.21 0.20

Most individuals occupy separate dens. Male may exclude other males from small rock outcrop inhabited by multiple females (Escherich 1981). Home range size in Alberta averaged 6.1 ha for males, 3.6 ha for females, much larger than for other woodrat species; females moved up to 470 m from the nest (Topping and Millar 1996). Average population density is about 1 per 20 acres (Banfield 1974).

Comments: Active throughout the year. Primarily nocturnal but may be seen during the day.

Observations: Little is known about the longevity of these animals, but one captive specimen lived for 5.8 years (Richard Weigl 2005).

Some aspects of the reproductive cycle of bushy-tailed woodrats are still under debate. These animals have been considered polygamous, polygynous, and/or promiscuous by various authors. Often these conclusions have been based not on actual observed matings, but on the size and relative overlap of male and female ranges. Breeding chiefly occurs in spring and summer (May through August). Females have small litters (up to six young at a time, though litter sizes over four tend to suffer losses since the female has only four mammary glands) but may have up to three litters per year. Modal litter size is three. Females have been observed breeding as soon as twelve hours after giving birth, and be may pregnant with one litter while nursing another. Males fight for access to mates, both through scent marking and actual physical contact. Fights consist largely of biting and scratching and may result in serious injury. Gestation period in captivity is 27-32 days. Newborns weigh approximately 15 g. Eyes open at around 15 days old, and weaning occurs at 26-30 days.

Males are heavier than females from early in development on. By weaning, males weigh 120-150 g, and females weigh 85-135 g. Females do not alter their foraging movements between pregnancy, lactation, and the post-reproductive period -- even though nutrient demands are higher at certain stages. Heavier females tend to have significantly more males in their litters than lighter females. Males are larger and require more energy to raise, though after weaning female offspring tend to reap more rewards from their mothers via philopatry (see "Behavior" section below). Females breed for the first time when they are yearlings.

(Egoscue, 1962; Escherich, 1981; Finley, 1990; Hickling et al., 1991; Moses and Millar, 1992; Moses et al., 1995; Topping and Millar 1996a; 1996b)

Average birth mass: 13.5 g.

Average gestation period: 30 days.

Average number of offspring: 3.68.

Average age at sexual or reproductive maturity (female)
Sex: female: 353 days.

Breeding peaks in spring. Gestation lasts about five weeks. Up to 2-3 litters/year. Litter size is about 3-4. Births occur April-August in California. Young males disperse by 2.5 months, many females breed in natal area. Commonly 1 adult male with 1-3 adult females (Escherich 1981).

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Specimens with Barcodes: 8
Species With Barcodes: 1

Year Assessed

Assessor/s

Reviewer/s

Justification

History

• 1996
  Lower Risk/least concern

Neotoma cinerea is not in any danger, and I did not find any literature discussing the problems of conservation of this species.

IUCN Red List of Threatened Species: least concern

Canada

Rounded National Status Rank: N5 - Secure

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Population

Population Trend

Major Threats

More info for the terms: density, fire management, high-severity fire, low-severity fire, mixed-severity fire, wildfire

As of 2006, there was no research on the effects of wildfire or prescribed burning on the bushy-tailed woodrat. Data are needed to make detailed management recommendations. Based on the habitat requirements for the bushy-tailed woodrat, fire management generalizations may be possible. Bull [24] recommends that if maintaining a viable population density for a particular animal is a management goal, then the habitat requirements for a species and the ecological processes resulting from fires must be assessed. Mixed-severity FIRE REGIMES may be beneficial for the bushy-tailed woodrat due to the mosaic of landscapes that are created [3,81]. Habitat corridors may be important to connect suitable habitat [29].

High-severity wildfire and prescribed burns may have negative effects on the bushy-tailed woodrat due to the loss of coarse woody debris, mistletoe brooms, and food sources. Plants eaten by the bushy-tailed woodrat may not regenerate for several years after severe fire [97,119]. Low-severity fire may not have as great an impact on bushy-tailed woodrats as high-severity fire. Any type of fire prescription including an objective of maintaining bushy-tailed woodrat habitat should mitigate the loss of coarse woody debris, dwarf mistletoe brooms, and snags [82].

More info for the terms: cover, density, forbs, shrubs, snag

Due to their dependence on trees, arboreal rodents such as the bushy-tailed woodrat are sensitive to timber harvesting [71] and may experience population declines in intensively managed areas [13]. Huff and others [71] rated the vulnerability of arboreal mammal species to local extirpations resulting from the fragmentation or loss of old-growth Douglas-fir forests. The index ranged from "1-low vulnerability", to "10-high vulnerability". The bushy-tailed woodrat was rated a "4" [71].

Coarse woody debris is an important habitat element for the bushy-tailed woodrat, especially in the Pacific Northwest [21,26,34,35,39,82,85,94,96,124] (see Preferred Habitat). Specific information about the density and types of logs required to provide viable habitat for bushy-tailed woodrat populations is unavailable [24]; however, loss of logs due to timber management or fire should be mitigated due to their importance for cover [82]. According to Pearson [96], coarse woody debris management should focus on maintaining a diverse array of sizes and decay classes for various animal species. Suggestions for coarse woody debris management include the creation of debris piles from thinning slash, and management of streamside habitat to restore coarse woody debris and complex vegetation structure [34]. For detailed recommendations about how to manage trees and logs in the Interior Columbia River Basin, see Bull and others [26]. For information about snag management for wildlife use, see Wellersdick and Zalunardo [124] and Pearson [96].

Managing for habitat patchiness may be suitable for the bushy-tailed woodrat [26,34]. Carey and others [31,33] suggest variable-density thinning in wet Douglas-fir and western hemlock forests in western Washington, with the retention of large snags and woody debris on the scale of 0.5- to 1.2-acre (0.2 to 0.5 ha) patches.

Livestock grazing: Bushy-tailed woodrats may either be negatively or positively affected by grazing by domestic livestock in mixed-conifer and spruce (Picea spp.)-fir (Abies spp.) forests in Arizona and New Mexico, depending on the grazing regime. Seed production of shrubs and forbs could be increased by grazing; however, heavy livestock use may degrade woody cover. Bushy-tailed woodrats are a "priority species" in Arizona and New Mexico. This means that bushy-tailed woodrats should receive greater consideration than non-priority wildlife species during development of management strategies related to livestock grazing [131].

Other: When bushy-tailed woodrat density was compared between unchained and chained areas in a mature pinyon-juniper (Pinus edulis-Juniperus osteosperma) woodland in the Piceance Basin, Colorado, density was greatest (n=8 individuals) in unchained control areas. Each study area consisted of 3 trapping grids, which included 32 trap stations (4 x 8 feet (1 x 2m)) at intervals of 49 feet (15 m). In 1-year-old chained areas, bushy-tailed woodrat density was 5 per trapping grid. Bushy-tailed woodrats were absent in 8-year-old or 15-year old chained areas [93]. O'Meara and others [93] suggest interspersing blocks of chained and unchained vegetation to maintain pinyon-juniper woodland species such as the bushy-tailed woodrat.

Conservation Actions

Bushy-tailed woodrats are attracted to shiny items and often steal them from campsites or buildings. They can be a pest species throughout their range as they find a way into buildings and establish den sites.

Bushy-tailed woodrats are important to humans for several reasons. They are important to paleontologists and paleoclimatologists not only because their middens preserve easily-dated plant macrofossils, but also because this species incorporates lots of bones into its middens as well. Packrat middens are a major source of information about Pleistocene paleoclimates and paleoecology in the western United States.

Neotoma cinerea is also important as a prey species. For instance, the bushy-tailed woodrat is one of the major food items for northern spotted owls, a species which is in jeopardy because of range reductions due to logging. The carrying capacity of owls in a particular habitat is largely dependent upon the density of their prey. Interestingly, however, Neotoma cinerea is least frequent in old-growth forests, and found more frequently in more recently cut and open habitats.

(Frase and Sera, 1993; Rosenberg et al., 1994; Vaughan, 1990)