Chapter XII: Part 12

Deer mice are the most abundant mice in Washington. They occur at sea level on the ocean beaches and above timber-line, even breeding in the Arctic-alpine Life-zone. They occur on the islands in Puget Sound, the lowland marshes and deciduous thickets of western Washington, the great conifer forests, the alpine cirques and mountain parks, and the deserts of eastern Washington. Almost everywhere they are the commonest mammal encountered. They make their homes in city dwellings, under logs or in hollow trees in the forest, in the burrows of larger rodents and, if necessary, in burrows of their own construction.

Nests are usually cup-shaped masses of soft material, 4 to 8 inches in diameter with central cavities 2 to 3 inches in diameter. Materials utilized include dry grass, shredded bark, rope, rags, newspaper, moss, cattail fluff, fur, wool, and feathers. One nest discovered in the attic of an old building near Coulee City, Grant County, consisted of the mummified body of a wood rat (_Neotoma cinerea_). The fur of the arched body of the rat formed one side of the nest, while the fur of the far side of the body had been plucked to form the remainder. In the extensive marshes along Lake Washington, King County, deer mice occupy the ball-shaped nests of tule wrens (_Telamtodytes palustris_). These are constructed entirely of fragments of cattail leaves and cattail fluff and are placed in the cattail rushes about four feet above the wet ground of the marsh. Other deer mouse nests were found in an unused typewriter, in the pocket of an old coat, in a window frame, under a piece of tar paper on the ground, in a cavity in the ground under a board, between a ceiling and a loose bit of roofing paper, under rocks and logs, in hollows in logs, and in an unused nest of a wood rat. Where plant cover is dense, nests are placed on the surface of the ground, as under thick growths of tumbleweed (_Salsola_) in eastern Washington.

Deer mice are definitely nocturnal. Of thousands of specimens trapped only a few were taken in the daytime. Two of these were taken in a rock slide at Pass Creek Pass, Pend Oreille County, on the same day, and some unusual conditions may have incited them to travel in daylight. Deer mice are active throughout the winter and their lacy footprints are seen on the snow in below-freezing weather. They are mainly terrestial but one race (_oreas_) is at least partly arboreal for it is often taken in traps set in trees for flying squirrels. One was caught in a trap set 50 feet from the ground. All are good climbers, and _oreas_ is perhaps the best. One was watched as it climbed the rough cedar shake wall of a cabin, ran upside-down across three feet of rough ceiling, and descended the opposite wall head first. They are equally agile in climbing rocks and cliffs.

The ordinary gait of the deer mouse is a steady run. When frightened it may leap a distance of one foot or more. When surprised in its nest it usually remains in the vicinity, hopping about in confusion, returning time after time to the exposed nest.

The food of deer mice consists principally of vegetable material such as seeds, nuts, berries, and the soft parts of fleshy plants. Mushrooms and lichens are eaten. Insect remains are present in small quantities in most stomachs examined. Flesh is also eaten and small mammals caught in traps are often eaten by deer mice. Cannibalism appears to be common only in captivity.

Deer mice are often heavily parasitized by tapeworms and roundworms. Virtually all of the deer mice taken on Jones Island in the San Juan Islands had livers so infected by the eggs of a nematode worm as to be swollen to several times their natural size, and had a yellow, crystalline appearance. The maggots of parasitic flies often occur in the anal and genital region of deer mice, effectively sterilizing some individuals.

Predatory snakes, birds, and mammals doubtless kill and eat deer mice. Strangely enough, although deer mice may be the commonest mammal in an area, the pellets of owls collected in the same area usually contain the remains of relatively few deer mice. The impact of owls seems to be greatest upon mice, such as _Microtus_, which follow definite runways.

The breeding season of the deer mouse extends over most of the spring and summer. Growth and development of the young of _Peromyscus m. oreas_ have been discussed by A. Svihla (1936A). Embryos found varied in number from 2 to 8 with a mean of 4.5.

=Peromyscus maniculatus oreas= Bangs

_Peromyscus oreas_ Bangs, Proc. Biol. Soc. Washington, 12:84, March
24, 1898.

_Peromyscus akeleyi_ Elliot, Field Columb. Mus. Publ. 30., zoöl.
ser., 1:226. February 1, 1899 (type from Elwha River, Olympic
Mountains, Washington).

_Peromyscus maniculatus oreas_ Osgood, N. Amer. Fauna, 28:51,
April 17, 1909.

_Type._--Obtained on Church Mountain, 6,500 ft., Mt. Baker Range,
near the U. S. boundary, British Columbia, by Allan Brooks on
August 29, 1896; type in Museum of Comparative Zoölogy.

_Racial characters._--Size large; tail more than 50 per cent of
total length; color of upper parts reddish.

_Measurements._--Twenty-five males and 15 females average: total
length 202; length of tail 110; hind foot 22.6; ear 18.7.

_Distribution._--From the Cascade Mountains west to the Pacific
Ocean, save for the Puget Sound area and a narrow band extending
southward nearly to the Columbia River. Marginal localities along
the west side of Puget Sound are: Deer Park (W.W.D.), Lake Cushman
(W.W.D.), and Kelso (M.V.Z.). Marginal localities on the west side
of the Cascade Mountains are: Tomyhoi Lake (W.W.D.), Forks of
Skykomish River (W.W.D.), North Bend (W.W.D.), Mt. St. Helens
(V.B.S.) and Yacolt (M.V.Z.). Marginal localities on the east
slope of the Cascade Mountains are: Grouse Creek (W.W.D.), Lake
Wenatchee (W.W.D.), Easton (W.W.D.), Morrison Springs Ranger
Station (W.W.D.) and Wind River C.C.C. Camp (W.W.D.).

=Peromyscus maniculatus hollisteri= Osgood

Peromyscus maniculatus hollisteri Osgood, N. Amer. Fauna, 28:62,
April 17, 1909.

_Type._--Obtained at Friday Harbor, San Juan Island, San Juan
County, Washington, by N. Hollister on October 23, 1903; type in
United States National Museum.

_Racial characters._--Similar to _oreas_ but darker, less reddish,
and with much shorter tail. Length of tail about 40 per cent of
total length.

_Measurements._--Populations of deer mice on the various islands
vary slightly in average measurements. The average measurements of
10 males and 10 females from San Juan Island, 20 males and 15
females from Blakeley Island, and 20 males and 15 females from
Cypress Island, are respectively: total length 189, 183, 179;
length of tail 87, 82, 79; hind foot 22.8, 22, 19.5; ear 19.4,
18.7, 19.5; weight 33, 29, 32 grams.

_Distribution._--The San Juan Islands, San Juan and Skagit
counties, in northern Puget Sound.

=Peromyscus maniculatus austerus= (Baird)

_Hesperomys austerus_ Baird, Proc. Acad. Nat. Sci. Philadelphia,
7:336, 1855.

_Sitomys americanus austerus_ Allen, Bull. Amer. Mus. Nat. Hist.,
5:192, August 18, 1893.

_P[eromyscus]., austerus_ Bangs, Amer. Nat., 31:75, January 1,
1897.

_Peromyscus maniculatus austerus_ Osgood, N. Amer. Fauna, 28:63,
April 17, 1909.

_Type._--Obtained at Old Fort Steilacoom, Pierce County,
Washington, by J. G. Suckley, probably on January 20, 1854; type in
United States National Museum.

_Racial characters._--Similar to _oreas_ but smaller with
relatively shorter tail; tail narrower at base, less sharply
bicolor; upper parts duller, browner, less reddish. In _oreas_ the
tail is usually more than 100 mm. In _austerus_ the tail is
usually less than 90 mm.

_Measurements._--Twenty-seven males and 23 females from Seattle,
King County, average: total length 180.5; length of tail 88.6;
hind foot 21; ear 18. The average weight of 15 adults is 21 grams.

_Distribution._--The Puget Sound area and south to the Columbia
River in a narrow band through the lowlands. Marginal localities
on the west side of Puget Sound are: Port Angeles (W.W.D.),
Bremerton (W.W.D.), 4 miles north of Shelton (W.W.D.), Tenino
(W.W.D.) and Mouth of Klama River (M.V.Z.). Marginal localities on
the east side of Puget Sound are: Bellingham (W.W.D.), Arlington
(W.W.D.), Everett (W.W.D.), 4 miles east of Monroe (W.W.D.), Fall
City (W.W.D.), and Vancouver (W.W.D.).

=Peromyscus maniculatus rubidus= Osgood

_Peromyscus oreas rubidus_ Osgood, Proc. Biol. Soc. Washington,
14:193, December 12, 1901.

_Peromyscus maniculatus rubidus_ Osgood, N. Amer. Fauna, 28:65,
April 17, 1909.

_Type._--Obtained at Mendocino City, California, by J. A. Loring on
November 17, 1897; type in United States National Museum.

_Racial characters._--Closely similar to _austerus_ but paler with
longer skull. Specimens from Washington are almost purplish-brown
in appearance.

_Measurements._--Six males and 2 females from Puget Island,
Wahkiakum County, average: total length 177; length of tail 89;
hind foot 21.9; ear 18.7.

_Distribution._--This is the deer mouse of the humid coastal belt
of Oregon and California. It enters Washington only at Puget
Island, Wahkiakum County, in the Columbia River.

=Peromyscus maniculatus gambelii= (Baird)

_Peromyscus gambelii_ Baird, Mamm. N. Amer., Pacific R. R. Reports,
8:464, 1857.

_Sitomys americanus gambelii_ Allen, Bull. Amer. Mus. Nat. Hist.,
5:190, August 18, 1893.

_P[eromyscus]., t[exanus]. gambelii_ Mearns, Proc. U. S. Nat.
Mus., 18:446, March 25, 1896.

_Peromyscus maniculatus gambeli_ Osgood, N. Amer. Fauna, 28:67,
April 17, 1909.

_Type._--Obtained at Monterey, Monterey County, California, by W.
P. Trowbridge; skin catalogued on January 4, 1853; type in United
States National Museum.

_Racial characters._--Size small; tail short; color pale, varying
from buffy gray to rich buff; rarely dark reddish brown.

_Measurements._--Twenty-five males and 15 females average: total
length 160; length of tail 71; hind foot 19.8; ear 17.7.

_Distribution._--The Columbian Plateau. Intergradation with
_oreas_ occurs between the Columbia River and the Cascade
Mountains. Marginal records on the west are: Chelan (W.W.D.),
Leavenworth (W.W.D.), Cle Elum (W.W.D.), Satus Pass (W.W.D.), Lyle
(V.B.S.). Marginal localities on the north are: Chelan (W.W.D.), 5
miles north of Coulee (W.W.D.), Sprague (V.B.S.) and Steptoe Butte
(M.V.Z.).

=Peromyscus maniculatus artemisiae= (Rhoads)

_Sitomys americanus artemisiae_ Rhoads, Proc. Acad. Nat. Sci.
Philadelphia, p. 260, October 23, 1894.

_Peromyscus texanus artemisiae_ Miller and Rehn, Proc. Boston Soc.
Nat. Hist., 30:84, December, 1901.

_Peromyscus maniculatus artemisiae_ Osgood, N. Amer. Fauna, 28:58,
April 17, 1909.

_Type._--Obtained at Ashcroft, British Columbia, by S. N. Rhoads on
July 5, 1892; type in Philadelphia Academy of Sciences.

_Racial characters._--Similar to _gambelii_ but darker, more
reddish; often with longer tail.

_Measurements._--Ten males and 10 females from northeastern
Washington average: total length 167; length of tail 80; hind foot
20; ear 17.8.

_Distribution._--Northeastern Washington and the Blue Mountains of
southeastern Washington, extending west, in northeastern
Washington, to Conconully (W.W.D.) and south to Duly Lake
(W.W.D.).

=Neotoma cinerea= Ord

Bushy-tailed wood rat

_Description._--The bushy-tailed wood rat is slightly larger than the common Norway or brown rat. The head and body measure about 12-1/2 inches and the tail about 3-1/2 inches. It resembles the deer mouse in general proportions. The ears are large and naked and the black eyes are large and protruding. The tail is bushy, squirrel-like. The feet are small and have furry soles. The fur is soft and silky. Adults are brownish gray above with white underparts and a gray tail. Young individuals have blue-gray upper-parts.

Wood rats range over most of North America. They exhibit great variation, especially in the southwestern United States. The bushy-tailed species occurs in the western United States and Canada. Wood rats are notorious for invading buildings in the mountains and in the desert. However, their natural habitat is broken rock or talus. This habitat preference accounts for their distribution in Washington, for talus is common except in the humid subdivision of the Transition Life-zone. Wood rats are probably most abundant in the talus slides of the Columbian Plateau, especially in the canyon of the Columbia River and in Moses and Grand coulees. They are common in all the mountainous areas in the state where high altitudes and steep slopes result in the accumulation of talus. Wood rats range from sea level to 10,000 feet elevation on Mount Rainier and from the Upper Sonoran to the Arctic-alpine life-zones. Great horned owls and probably all of the carnivores that share the range of the wood rat prey on it to some extent. Sperry (1941: 15) lists _Neotoma_ in four per cent of 8,339 coyote stomachs gathered throughout the United States.

Wood rats in Washington are definitely nocturnal and are rarely seen in daylight. On January 10, 1939, however, near Colville, Stevens County, a companion and I were sitting on the porch of a deserted shack eating lunch. Suddenly a wood rat darted out of the open door into the full sunlight and tugged at a can, containing a few drops of tomato juice, which one of us was holding in his hand. When the rat looked up and saw the human, it hastily retreated. The wood rat has a habit of flattening its body tightly against the ground when observed and also of "drumming" with its feet when excited. This habit is shared by the snowshoe rabbit and the spotted skunk. A captive specimen "drummed" by lifting its back feet, alternately, about one-half inch from the surface of a piece of wood and striking downward with surprising power. The agility of the wood rat was demonstrated near Wallula where we watched a specimen by the light of a flashlight as it climbed an almost vertical rock wall, taking advantage of small fractures for toe-holds.

Wood rats are far from noiseless in their nocturnal activities. Near Moses Coulee, Douglas County, wood rats were heard from a distance of 50 feet as they scampered back and forth through a concrete culvert under the highway.

Many species of wood rats build complicated stick houses in which they live. In Washington, elaborate stick houses are sometimes built but are usually not occupied. In the attic of an old building near Pend Oreille Lakes, Stevens County, two large and complicated houses were discovered. These were built of sticks, paper and other debris and measured more than three feet in diameter. Three small, cup-shaped nests resembling those of a bird, made of soft grasses, moss, and shredded paper were found on the attic floor ten feet or more from the stick houses. These nests gave every indication of being used, while the piles of sticks contained no nests and seemed never to have been occupied. Near Moses Lake, Grant County, a wood rat house built in the rafters of an old shed was constructed entirely of tumbleweeds (_Salsola pestifer_). This house was spherical in shape and measured more than five feet in diameter. It appeared to be unoccupied and a wood rat, probably its builder, was living under the floor of the shed. Most wood rat houses consist of a half-dozen sticks arranged in a crevice in a rock pile or a cave. Wood rats were placing fresh material on a house in the Wenatchee National Forest on January 17, 1939, when there was two feet of snow on the ground and the temperature was hovering around zero. The house measured about one cubic yard and consisted of _Ceanothus_ leaves and steins, with some twigs of fir (_Abies_). It was built under a bunk in a broken-down cabin left by deer hunters.

The collecting habit of the wood rat has gained it the name "pack-rat." Taylor (1920A: 91) lists the following materials from a wood rat nest on Mt. Rainier: _Nesting material_: rags, leaves, paper, thumb of a glove, string, thongs, oakum; _Food_: apple core, onion peel, bacon rind, raisins, 10 bars of chocolate, figs, puff balls, bread crust, meat scraps, cantaloupe rind, potatoes, dried apricots, lemons, mushrooms, beans, peanuts, banana, 15 lumps of sugar; _Miscellaneous_: dime, coffee can cover, paraffin from jelly glass, bones, 19 pieces of candles and several cakes of soap.

As a rule only one or two wood rats are trapped at a given locality, indicating that the species is not gregarious. The presence of wood rats in a building, cave, mine tunnel, or talus slide can be detected in several ways. The white, mineral-like incrustation formed by the urine of many generations of wood rats is usually conspicuous on rocks near their homes. A strong musky odor pervades the atmosphere in every habitat occupied by wood rats. Wood rat feces, consisting of hard, black cylinders one-half inch long and three-sixteenths of an inch in diameter, are invariably found scattered on stones or exposed areas of ground.

The food of the bushy-tailed wood rat is varied and includes insects and vegetation. A captive specimen that escaped in the University of Washington Zoölogical Laboratories killed and ate a number of lizards.

Embryos found from April 18 to June 14 varied in number from 3 to 5.

=Neotoma cinerea occidentalis= Baird

_Neotoma occidentalis_ Baird, Proc. Acad. Nat. Sci. Philadelphia,
p. 335, 1855.

_Neotoma cinerea occidentalis_ Merriam, N. Amer. Fauna, 5:58, July
30, 1891.

_Type._--Obtained at Shoalwater Bay (Willapa Bay), Pacific County,
Washington, by J. G. Cooper, in June, 1854; type in United States
National Museum.

_Racial characters._--Size large; color of upper parts cinnamon
brown.

_Measurements._--A male and a female from Glade Creek, 1/2 mile
north of the Columbia River, Benton County, measure, respectively:
total length 425, 395; length of tail 181, 176; hind foot 50, 44;
ear 32, 31; weight 532.5, 330.0 grams.

_Distribution._--Throughout the state except in the Blue
Mountains.

_Remarks._--Specimens from the Olympic Mountains and western Washington are slightly duller-colored than specimens from eastern Washington and young from western Washington are more bluish, less gray, than young individuals from the Columbian Plateau. The specimens from the Columbian Plateau show some resemblance to _alticola_. Specimens from northeastern Washington are more like typical _occidentalis_.

=Neotoma cinerea alticola= Hooper

_Neotoma cinerca alticola_ Hooper, Univ. California Publ. Zoöl.,
42:409, May 17, 1940.

_Type._--Obtained at Parker Creek, 5,500 ft., Warner Mountains,
Modoc County, California, by N. B. Stern on June 22, 1916; type in
Museum of Vertebrate Zoölogy.

_Racial characters._--Similar to _Neotoma c. occidentalis_ but
slightly paler, with paler hind feet and narrower sphenopalatine
vacuities.

_Measurements._--A female from Stay-a-while Spring, Columbia
County, measures: total length 387; length of tail 171; hind foot
43; ear 33; weight 330 grams.

_Distribution._--Southeastern Washington, south of the Snake
River.

_Remarks._--The only adult specimen available from the Blue Mountains shows well the characters attributed to _alticola_.

=Synaptomys borealis wrangeli= Merriam

Northern lemming mouse

_Synaptomys (Mictomys) wrangeli_ Merriam, Proc. Biol. Soc.
Washington, 10:63, March 19, 1896.

_Synaptomys (Mictomys) truei_ Merriam, Proc. Biol. Soc.
Washington, 10:62, March 19, 1896 (type from Skagit Valley, Skagit
County, Washington).

_Synaptomys borealis wrangeli_ Howell, N. Amer. Fauna, 50:26, June
30, 1927.

_Type._--Obtained at Wrangel, Alexander Archipelago, Alaska, by C.
P. Streator on September 6, 1895; type in United States National
Museum.

_Racial character._--Dark color.

_Distribution._--The northwestern Cascades, from Mt. Baker
northward.

_Remarks._--The relationship of this race to _artemisiae_ remains to be worked out.

_Description._--Lemming mice may be recognized by their short, thick bodies, slightly larger than the bodies of the common house mouse (_Mus_); short tails, which are less than 20 per cent of their total length; small, inconspicuous ears; and grooved upper incisors.

Mice of the genus _Synaptomys_ range over much of boreal North America. Two species and eleven races are recognized by Howell (1927B: 9). _Synaptomys borealis_ ranges westward across Canada from Labrador to the Pacific Coast and from Alaska south to Washington. The lemming mice are terrestrial and inhabit runways similar to those of meadow mice (_Microtus_). They are alpine in distribution. Shaw (1930: 7-10) found them among typical annual herbs in a cold, boggy mountain valley. Other than this, nothing is known of the species in Washington. Indeed little is known of the life history of any member of the genus.

The lemming mouse possesses four pairs of mammae, two pectoral and two inguinal. It is the most primitive of the microtines. It seems to be of boreal origin but is not known from the Old World. It was evidently forced southward by the Pleistocene glaciers into Washington and is now retreating northward in the wake of the ice. The only specimens recorded from Washington are from the northern border of the state.

=Phenacomys intermedius= Merriam

Heather vole

_Description._--Heather voles are heavy-bodied, short-legged mice, closely similar in general appearance to other microtines that occur in Washington. Their dull, brownish upper parts, lacking a distinct reddish dorsal stripe, separate them from the red-backed mice (_Clethrionomys_) and the lack of grooves on their upper incisors separates them from _Synaptomys_. Their relatively short tail (30 per cent or less of their total length) separates them from most meadow mice (_Microtus_). There are no external characters which serve to separate them from all species of _Microtus_ and the teeth must be examined certainly to identify _Phenacomys_. In _Microtus_ the angles between the cusps of the inner and outer sides of the lower molars are of approximately equal depth, but in _Phenacomys_ the angles on the inner side of the lower molars are at least twice as deep as those of the outer side of the jaw. In addition the molars of _Phenacomys_ are rooted while those of _Microtus_ are not.

The heather voles and their relatives are primitive microtines that range through boreal North America including the higher parts of the Rocky Mountains and the cool area along the Pacific Coast. Several species are included in the genus: an arctic form (_ungava_), a lowland Pacific Coastal species (_albipes_), two tree-inhabiting species (_longicaudus_ and _silvicola_) and a mountain species (_intermedius_). Thus far only _intermedius_ has been found in Washington but further search may reveal that one or more of the arboreal species and possibly _albipes_ are also present.

Heather voles are alpine animals, seldom occurring below the Hudsonian Life-zone. They are rare as compared with most microtines, and are seldom taken in traps, even by the experienced collector of small mammals. Evidence of their presence is most often found in the dense meadows of heather (_Cassiope_ and _Phyllodoce_) high on the mountains. Here their feces, runways, and old winter nests are not uncommon, and heather voles may be far more abundant than trapping records indicate. They are not restricted to the vicinity of heather, however, for one of my specimens was taken in a marshy willow thicket near Stevens Pass in King County, one in a patch of skunk-cabbage in a grassy glacial cirque near Tomyhoi Lake in Whatcom County, and one at the edge of a snowbank on a steep hillside at Deer Park, Clallam County. In each of these places, however, there were heather meadows within a thousand yards. Shaw (1924A: 12-15) also found the heather mouse on "comparatively dry hill slopes" and reports that it "rather characteristically occurs in such log-tangled areas as former fire zones."

The winter nests of _Phenacomys intermedius_ are placed on the surface of the ground and in the season when occupied are deeply buried under the snow. They are spherical or oval in shape, six to eight inches in diameter and with a side entrance. One examined by Shaw was "formed of white heather twigs, the interstices being filled with leaves of huckleberry." It was "lined with finely shredded grass." All those examined by me were composed of grass and lichens.

The principal foods of the heather vole seem to be white heather (_Cassiope mertensiana_) and huckleberry (_Vaccinium_). Red heather (_Phyllodoce empetriformis_) is not eaten. Shaw also lists beargrass (_Xerophyllum tenax_) and lousewort (_Pedicularis_) as eaten.

A burrow excavated and figured by Shaw, was slightly more than a yard long and contained four young in a nest situated but a few inches from one of the three entrances. The nest was made of grass and moss. A female taken at Tye, King County, contained 4 embryos on May 28, 1939. One taken at Pass Creek Pass, Pend Oreille County, contained 3 small embryos on June 14, 1938.

=Phenacomys intermedius intermedius= Merriam

_Phenacomys intermedius_ Merriam, N. Amer. Fauna, 2:32, October 30,
1889.

_Phenacomys intermedius intermedius_ Howell, N. Amer. Fauna,
48:15, October 12, 1926.

_Type._--Obtained 20 miles north-northwest of Kamloops, 5,500 ft.
elevation, British Columbia, by G. M. Dawson on October 2, 1888;
type in United States National Museum.

_Racial characters._--Size small; color of upper parts brownish
gray; skull small.

_Measurements._--A female from Pass Creek Pass, Pend Oreille
County, measured: total length 127; length of tail 29; hind foot
17; weight 25 grams.

_Distribution._--Known only from extreme northeastern Washington
at Pass Creek Pass (W.W.D.) and the Blue Mountains.

=Phenacomys intermedius oramontis= Rhoads

_Phenacomys oramontis_ Rhoads, Amer. Nat., 29:941, October, 1895.

_Phenacomys olympicus_ Elliot, Field Columb. Mus. Publ. 30, zoöl.
ser., 1:225, February 1, 1899 (type from Happy Lake, 5,000 ft.,
Clallam County, Washington).

_Microtus (Lagurus) pumilus_ Elliot, Field Columb. Mus. Publ. 30,
zoöl. ser., 1:226, February 1, 1899 (type from Happy Lake, 5,000
ft., Clallam County, Washington).

_Phenacomys intermedius olympicus_ Howell, N. Amer. Fauna, 48:21,
October 12, 1926.

_Phenacomys intermedius oramontis_ Anderson, Canadian Field Nat.,
56:59, June 8, 1942.

_Type._--Obtained on Church Mountain, 6,000 ft., Mt. Baker Range,
British Columbia, just north of international boundary, by A. C.
Brooks on August 6, 1895; type in Philadelphia Academy of Natural
Sciences.

_Racial characters._--Similar to _intermedius_ but darker, browner
above and deeper gray beneath; skull large and heavy.

_Measurements._--A female from Tye, King County, measures: total
length 152; length of tail 40; hind foot 19; ear 12. A female from
Tomyhoi Lake, Whatcom County, measures: 170; 45; 20; 15.

_Distribution._--The Cascade and Olympic mountains, from Tomyhoi
Lake (W. W. D.) on the north, to Mt. Adams (Taylor and Shaw,
1929:23) on the south.

=Clethrionomys gapperi= (Vigors)

Gapper red-backed mouse

_Description._--Red-backed mice are heavy-bodied, short-tailed and short-legged mice, similar in general appearance to the meadow mice (_Microtus_). Unlike the meadow mice, they possess rooted molars, a primitive character. They do not have grooved incisors, like _Synaptomys_, or the great difference in the depth of the angles of the lower molars that characterizes both _Synaptomys_ and _Phenacomys_. Externally _Clethrionomys_ may be recognized by the broad red dorsal area from which they obtain their common name. Their sides are grayish or dusky and the undersides buffy white.

The red-backed mice, including more than one species, range over the boreal parts of the Old and New World. In America they are found in most of Alaska, Canada and the northern United States, and extend southward in the Rocky Mountains and along the Pacific Coast. The one species _Clethrionomys gapperi_ ranges across southern Canada from the Atlantic to the Pacific, extending southward in forested areas to New Mexico. They usually live in clearings in the forest. In the Pend Oreille Mountains _saturatus_ was common in damp, mossy talus slides, along with _Microtus longicaudus_ and _Phenacomys intermedius_. The _Clethrionomys_ outnumbered the two latter species combined by 25 to 1. In nearby forest, red-backed mice were scarce but no other microtines were found. In the Kettle River Mountains a week later, red-backed mice were rare. A single specimen was taken in a damp place in the forest; none was found in talus slides. Near Stevens Pass, King County, in the Cascades, _cascadensis_ was taken in equal numbers in talus slides and under logs in the forest. Near Dewey Lake, Yakima County, in the Cascades, I took them only in an extensive grassy meadow. In the Blue Mountains I found _idahoensis_ in the dense chaparral, far from forests.

Unlike _Microtus_, red-backed mice do not make runways, although they sometimes follow the runways of other mammals.

Taylor (1920B: 92) found red-backed mice breeding on Mount Rainier from early July to the middle of September. One female gave birth to four young in a nest in his duffle bag.

=Clethrionomys gapperi saturatus= (Rhoads)

_Evotomys gapperi saturatus_ Rhoads, Proc. Acad. Nat. Sci.
Philadelphia, p. 284, October 23, 1894.

[_Clethrionomys gapperi_] _saturatus_ Whitlow and Hall, Univ.
California Publ. Zoöl., 40:265, September 30, 1933.

_Type._--Obtained at Nelson, British Columbia, by S. N. Rhoads on
August 27, 1892; type in Philadelphia Academy of Sciences.

_Racial characters._--Size small, about 140 mm. in total length;
tail short, about one-third of total length; ears large,
projecting above fur; color of head and sides gray tinged with
yellowish; back with distinct red stripe; underparts whitish
tinged with buff.

_Measurements._--Five males and 10 females from Pass Creek Pass,
Pend Oreille County, average: total length 147; length of tail 43;
hind foot 18.3; ear 14.

_Distribution._--Northeastern Washington from Sherman Creek Pass
(W. W. D.) on the west to Pass Creek Pass on the east.

=Clethrionomys gapperi idahoensis= (Merriam)

_Evotomys idahoensis_ Merriam, N. Amer. Fauna, 5:66, July 30, 1891.

_Clethrionomys gapperi idahoensis_ Whitlow and Hall, Univ.
California Publ. Zoöl., 40:265, September 30, 1933.

_Type._--Obtained at Sawtooth (Alturas) Lake, 7,200 ft., Blaine
County, Idaho, by C. H. Merriam and V. Bailey, on October 4, 1890;
type in United States National Museum.

_Racial characters._--Similar to _saturatus_ but brain case longer
and narrower and dorsal area more reddish.

_Measurements._--Seven males and 6 females from the Blue Mountains
average, respectively: total length 138, 142; length of tail 41,
41; hind foot 18.7, 19.0; ear 13.6, 13.5; weight 20.5, 22.7 grams.

_Distribution._--The Blue Mountains of southeastern Washington.

=Clethrionomys gapperi cascadensis= Booth

_Evotomys gapperi saturatus_ Taylor and Shaw, Occ. Pap. Chas. R.
Conner Mus., no. 2:23, December, 1929.

_Clethrionomys gapperi cascadensis_ Booth, Murrelet, 26:27, August
10, 1945.

_Type._--Obtained 2 miles south of Blewett Pass, 3,000 ft.
elevation, Kittitas County, Washington, by G. G. Cantwell, on
October 30, 1921; type in United States National Museum.

_Racial characters._--Dark and dull with underparts dull buffy.

_Measurements._--Ten adults from the Cascade Mountains average
(Booth, 1945: 27): total length 162; length of tail 50; hind foot
19; ear 14.

_Distribution._--The Cascade Mountains, according to Booth (_loc.
cit._, p. 28), from Hannegan Pass south to Mount Adams. Marginal
localities listed are: Swamp Creek, Glacier Peak, McKenna, and Mt.
St. Helens. These, and other localities listed by Booth are not
plotted on the accompanying distribution map (fig. 111).

=Clethrionomys gapperi nivarius= (Bailey)

_Evotomys nivarius_ Bailey, Proc. Biol. Soc. Washington, 11:136,
May 13, 1897.

_Evotomys gapperi nivarius_ Taylor and Shaw, Occ. Papers Chas. R.
Conner Mus., no. 2:23, 1929.

_Clethrionomys nivarius_ Svihla, Murrelet, 12:54, May, 1931.

_Type._--Obtained on the northwest slope of Mt. Ellinor, 4,000 ft.
elevation, Mason County, Washington, by C. P. Streator, on July 9,
1894; type in United States National Museum.

_Racial characters._--Similar to _saturatus_ but paler throughout.

_Measurements._--Two males and a female from 1 mile northwest of
Lake Cushman, Mason County, average: total length 140; length of
tail 42; hind foot 18; ear 13.

_Distribution._--The Olympic Mountains, from Sol Duc Hot Springs
(W.S.M.) south and west at least to Staircase, on Lake Cushman
(W.W.D.).

=Clethrionomys californicus occidentalis= (Merriam)

California red-backed mouse

_Evotomys occidentalis_ Merriam, N. Amer. Fauna, 4:25, October 8,
1890.

_Evotomys pygmaeus_ Rhoads, Proc. Acad. Nat. Sci. Philadelphia, p.
284, October 23, 1894 (type from mouth of Nisqually River, Pierce
County, Washington).

_Evotomys gapperi occidentalis_ Taylor and Shaw, Occ. Papers Chas.
R. Conner Mus., no. 2:23, 1929.

_Clethrionomys occidentalis_ Hall, Murrelet, 13:79, September,
1932.

_Type._--Obtained at Aberdeen, Grays Harbor County, Washington, by
T. S. Palmer, on August 16, 1889; type in United States National
Museum.

_Measurements._--Ten males and 10 females average: total length
137; length of tail 45; hind foot 18; ear 12.3.

_Distribution._--The lowlands of western Washington, east at least
to Cottage Lake (W. W. D.).

_Remarks._--Specimens from the type locality of _occidentalis_ and other places along the ocean coast are larger and brighter in color than specimens from farther inland, but the difference appears to me to be insufficient to warrant subspecific separation of the two lots.

_Clethrionomys californicus_ resembles _Clethrionomys gapperi_ but is darker and duller in color with the red dorsal area more obscured and forming less of a stripe. _C. californicus_ is found in the forested lowlands of western Washington, Oregon, and northern California, and in the Cascades of Oregon. In Washington, it is confined entirely to the forest where it is trapped under logs and on the layer of dead needles at the bases of conifers. Mice of this species were numerous in the forest along the Pacific Coast on the Long Beach Peninsula and at Aberdeen, Grays Harbor County. At Lost Lake Prairie, Mason County, at the southeastern base of the Olympic Mountains, they were rather scarce, but were the only mammals taken in the deep woods. Near Shelton, Mason County, at the eastern edge of the Olympic Mountains, a number of specimens were taken along with twice as many _Peromyscus maniculatus_. At Cottage Lake, King County, near Seattle, they were rare, comprising about two per cent of the mammals taken in two weeks' trapping.

Almost nothing was learned of the habits of these mice. They seem to be rigidly restricted to a habitat where few plants other than trees grow. The stomachs examined contained pasty masses of finely chewed white vegetation with occasional gray particles that might have been bits of lichens. The mice do not make runways like those of _Microtus_.

=Microtus pennsylvanicus= (Ord)

Pennsylvanian meadow mouse

_Description._--The upper parts are dark blackish brown and the underparts grayish or whitish. The tail comprises about a fourth of the total length and the foot does not exceed 21 mm. These two features separate it from most other species of meadow mice. From _Microtus oregoni_ it may be separated by its larger size, blackish color and well-developed eyes. From _Microtus montanus_ it differs in being larger, darker, and in having a closed posterior loop on the innerside of the second upper molar.

_Microtus pennsylvanicus_ is the most common meadow mouse of the eastern United States. It ranges westward through Canada and southward in the Rocky Mountains. A number of races occur in this extensive range. In northeastern Washington the eastern meadow mouse is locally common, being confined to marshes and damp meadows. Well-used runways are made through the dense vegetation and piles of feces and blades of grass are deposited therein. A number of broods are raised in a season, for young of many different ages are taken together in midsummer.

On the Columbian Plateau this mouse lives in marshy areas about lakes and potholes. Narrow trails are constructed through the dense vegetation. It burrows in damp earth and some occupied burrows are half-full of seepage water. Cuttings found in runways show that the mice feed on a variety of plants, including sedge (_Carex_). In the Moses Lake area the breeding season begins in March. Embryos found March 24, 1940, varied from 4 to 7 in number. This species is cyclically abundant.

=Microtus pennsylvanicus funebris= Dale

_Microtus pennsylvanicus modestus_ Bailey, N. Amer. Fauna, 17:20,
June 6, 1900.

_Microtus drummondii_ Bailey, N. Amer. Fauna, 17:22, June 6, 1900.

_Microtus pennsylvanicus funebris_ Dale, Jour. Mamm., 21:338,
August 13, 1940.

_Type._--Obtained at Coldstream. 1,450 ft., 3-1/2 miles southeast
of Vernon. British Columbia, by T. P. Maslin. Jr., on August 2,
1937; type in Museum of Vertebrate Zoölogy.

_Racial characters._--Size medium; color reddish brown; fur short,
harsh; skull small and narrow.

_Measurements._--Three males from Newport, Pend Oreille County,
average: total length 165; length of tail 40; hind foot 20; ear
15.3.

_Distribution._--Northeastern Washington, west to Conconully
(Taylor and Shaw, 1929: 24) and east to Newport (W. W. D.).

_Remarks._--Specimens from northeastern Washington are larger and darker, more reddish and less gray, than _drummondii_. They are larger, more reddish, and have relatively narrower skulls, than _modestus_ from Colorado and Idaho. They closely resemble _funebris_ from south-central British Columbia, and are best referred to that race. Rand (1943: 123) considers _funebris_ a synonym of _modestus_ but I feel is incorrect in doing so.

=Microtus pennsylvanicus kincaidi= Dalquest

_Microtus montanus kincaidi_ Dalquest, Proc. Biol. Soc. Washington,
54:145, September 30, 1941.

_Type._--Obtained at The Potholes, 10 miles south of Moses Lake,
Grant County, Washington, by W. W. Dalquest on March 24, 1940; type
in Museum of Vertebrate Zoölogy.

_Racial characters._--Large size; dark blackish color; long fur;
wide, angular skull.

_Measurements._--Six male and 12 female topotypes average,
respectively: total length 176.6, 168.0; length of tail 45.1,
43.8; hind foot 20.8, 20.3; ear 14.0, 13.4.

_Distribution._--The Columbian Plateau, in the Grand Coulee area.

=Microtus montanus= (Peale)

Montane meadow mouse

_Description._--Montane meadow mice have short tails, flaring zygomatic arches, and heavily ridged skulls. They are small, about 6-1/2 inches long, and buffy-gray in color. Their short tails, less than one-third the length of head and body, and gray color separate them from all other Washington meadow mice.

Montane meadow mice are widely distributed in the southwestern United States, where numerous races are found. They occupy damp meadows and marshes in the arid subdivision of the Transition Life-zone of eastern Washington. They seem to require deep, dense cover of grasses, reeds, or sedges, near water. They are usually associated with harvest mice (_Reithrodontomys megalotis_), wandering shrews (_Sorex vagrans monticola_), and muskrats (_Ondatra zibethica_). Hawks and owls are their principal enemies, but predatory mammals and snakes probably kill many.

Montane meadow mice evidently are both diurnal and nocturnal; specimens were taken in the daytime as well as at night, and captives were active periodically day and night. Captives were extremely quick in their movements. If disturbed they sat up on their haunches and chattered indignantly. It was almost impossible to handle them without being bitten.

The trails of montane meadow mice are narrower than those of other meadow mice, and appear to be used the year around. Burrows are numerous where the mice are plentiful. A heap of damp earth marks the entrance to each burrow. One nest of _M. m. canescens_ near Lake Chelan, Chelan County, was under a log on a small knoll in a marsh. The nest was round, about 8 inches in diameter, and was composed of cattails, grasses, and moss.

_Microtus montanus nanus_ (Merriam)

_Arvicola (Mynomes) nanus_ Merriam, N. Amer. Fauna, 5:63, July 30,
1891.

_Microtus nanus_ Miller, Proc. Biol. Soc. Washington, 11:67, April
21, 1897.

_Microtus nanus nanus_ Miller, Bull. U. S. Nat. Mus., 128:409,
April 29, 1924.

_Microtus montanus nanus_ Hall, Proc. Biol. Soc. Washington,
51:133, August 23, 1938.

_Type._--Obtained in the Pahsimeroi Mountains, 9,300 ft., Custer
County, Idaho, by C. H. Merriam and V. Bailey on September 16,
1890; type in United States National Museum.

_Racial characters._--Size medium; color of upper parts brownish
gray; sides paler; underparts grayish white.

_Measurements._--A large male from Prescott, Walla Walla County,
measures: total length 168; length of tail 48; hind foot 20. A
female from Prescott, Walla Walla County, and a female from
Pullman, Whitman County, average: 133; 31; 18.5.

_Distribution._--Southeastern Washington, westward as far as 5
miles east of Wallula (M.V.Z.).

=Microtus montanus canescens= Bailey

_Microtus nanus canescens_ Bailey, Proc. Biol. Soc. Washington,
12:87, April 30, 1898.

_Microtus montanus canescens_ Hall, Proc. Biol. Soc. Washington,
51:133, August 23, 1938.

_Type._--Obtained at Conconully, Okanogan County, Washington, by J.
A. Loring, on September 12, 1897; type in United States National
Museum.

_Racial characters._--Size small; color of upper parts pale
brownish gray; sides yellowish gray. This race differs from
_Microtus m. nanus_ in generally paler, less brownish coloration.
It does not differ from _nanus_ in any distinctive cranial
features.

_Measurements._--Two male and 2 female topotypes average,
respectively: total length 151, 143; length of tail 35, 33.5; hind
foot, 19.5, 19.5. A series of 8 males and 6 females from Selah,
Yakima County, average, respectively: total length 151.7, 150.5;
length of tail 41.5, 40.1; hind foot 19.7, 18.8; ear 12.8, 13.0;
weight 47.2, 36.8 grams.

_Distribution._--The eastern foothills of the Cascade Mountains
from the British Columbian boundary south, probably to the
Columbia River. Recorded east to Benton City (Taylor and Shaw,
1929: 24).

_Remarks._--A large series from Selah, Yakima County, is somewhat intermediate between _nanus_ and _canescens_. These specimens from south of the Wenatchee Mountains are, however, more like _canescens_ in color than they are like _nanus_.

Bailey (1900: 32) records a specimen of this race from North Yakima as _Microtus canicaudus_.

=Microtus townsendii= (Bachman)

Townsend meadow mouse

_Description._--The Townsend meadow mouse is a large-bodied, long-furred mouse with a tail of moderate length. Head and body measure about 8 inches, the tail about 2-1/2 inches. The legs are short and the ears scarcely project through the fur on the head. In summer the color is dark reddish-brown. The winter color is dark brownish-black. Underparts are paler, more grayish brown, than are the upper parts. The tail is sparsely haired.

Townsend meadow mice occur west of the Cascade Mountains in California, Washington, Oregon, British Columbia, and on some British Columbian and Washington islands. The habitats of the two races of the Townsend meadow mice found in Washington are wholly in the humid subdivision of the Transition Life-zone but vary somewhat in nature. The race _townsendii_ lives in marshes or damp meadows, under cover of deep, rank vegetation. These mice avoid forested areas or dry brush, but sometimes occur in dry grass when it is deep enough to conceal them from enemies. The race _pugeti_ has been recorded from meadows, salt marshes, driftwood strewn on sea-beaches, areas of sparse, dry grass, and piles of rocks.

Townsend meadow mice are as diurnal as they are nocturnal; specimens have been trapped at almost all hours of the day and night. Their ordinary method of traveling is a slow run. When startled they make a dash for the nearest cover, into which they dive headlong. They make considerable noise while moving about and often may be heard from several feet away. Captives in the laboratory seemed rather dull and stupid as compared with other meadow mice.

In the fall, winter, and early spring the Townsend meadow mice keep to their runways. These runways are used by successive generations of mice, and often are worn into ditches several inches deep. In the late spring and summer, when the grass and other vegetation in their habitat is tall and rank, offering complete concealment, the runways are abandoned and cuttings of rejected food are found scattered over the surface of the ground.

The food of the Townsend meadow mice includes the succulent leaves and stems of many grasses and annuals. Near Seattle the staple summer food is the velvet grass (_Holcus lanatus_), although many other plants, including the horsetail (_Equisetum arvense_), are eaten. In winter the common cattail is eaten. Couch (1925: 200) found caches of the roots of mint (_Mentha canadensis_) stored by this species. As much as 14 quarts was found in a single cache.

The cup-shaped nests of Townsend meadow mice near Seattle were below ground. Embryos were found from May 4 to May 20 and varied in number from 5 to 8 with a mean of 7. In the San Juan Islands the nests of _M. t. pugeti_ were under driftwood.

=Microtus townsendii townsendii= (Bachman)

_Arvicola townsendii_ Bachman, Jour. Acad. Nat. Sci. Philadelphia,
8 (pt. 1):60, 1839.

_Arvicola occidentalis_ Peale, U. S. Expl. Exped., Mammalogy, p.
45, 1848 (type from Puget Sound).

_M[icrotus]. townsendi_ Miller, N. Amer. Fauna, 12:66, July 23,
1896.

_Microtus townsendii townsendii_ Svihla and Svihla, Murrelet,
14:40, May, 1933.

_Type._--Obtained on the Columbia River (probably on or near Sauvie
Island, Multnomah County, Oregon); type in Philadelphia Academy of
Natural Sciences.

_Racial characters._--Size large; skull narrow in interorbital
region.

_Measurements._--Eight males and 5 females from Clark and Pacific
counties, southwestern Washington, average, respectively: total
length 208.0, 208.4; length of tail 65.7, 66.0; hind foot 26.5,
25.4; ear 15.0, 14.6; weight 80.8, 76.7 grams. Thirteen males and
9 females from Seattle average, respectively: 211.8, 209.0; 71.2,
68.6; 25.7, 26.0; 15.8, 15.4.

_Distribution._--The lowlands of western Washington from
Bellingham (J.M.E.) south to Puget Island (V.B.S.).

=Microtus townsendii pugeti= Dalquest

_Microtus townsendii pugeti_ Dalquest, Murrelet, 21:7, April 1,
1940.

_Type._--Obtained at Neck Point, northwest corner of Shaw Island,
San Juan County, Washington, by D. H. Johnson, on July 10, 1938;
type in Museum of Vertebrate Zoölogy.

_Racial characters._--Size small; skull wide in interorbital
region, averaging about 4.0 mm. (3.8-4.2); basi-sphenoid truncate
posteriorly; upper incisors strongly curved.

_Measurements._--Two males and 6 females average: total length
182.6; length of tail 50.3; hind foot 23.2; ear 15.0.

_Distribution._--Found only on the San Juan Islands, San Juan and
Skagit counties.

_Remarks._--The islands occupied by this race of mouse were heavily glaciated by the last continental glacier (Vashon). Mice of the species _townsendii_ apparently migrated to the islands early in the Recent era, and under isolation developed the differences which now separate them from the mainland population.

=Microtus longicaudus= (Merriam)

Long-tailed meadow mouse

_Description._--The several races of this species vary from small to large in size. Their bodies are relatively longer and slimmer than those of the other meadow mice that occur in Washington. Their most distinctive feature is the long tail, only slightly shorter than the head and body. Their fur is rather coarse. The color varies from grayish brown to dull reddish brown with a brighter brown dorsal stripe. The tail is bicolor; black or dark brown above, yellowish below. The underparts are whitish gray.

Long-tailed meadow mice are widely distributed over the western United States, Canada, and Alaska. In Washington the long-tailed meadow mouse has been taken in many habitats. One specimen was taken along a small, temporary stream through sagebrush in the Upper Sonoran Life-zone. Others were found in marshes and near water in the arid subdivision of the Transition Life-zone. In the humid subdivision of the Transition Life-zone they are not uncommon in damp areas along the ocean coast, but are rather rare in dry, grassy habitats. In the Canadian and Hudsonian life-zones they are fairly common in forest-free, grassy places, being most abundant near talus slides. Altitudinally they range from sea level to 6,000 feet.

Long-tailed meadow mice are rather rare. Several were taken in the daytime at Round Top Mountain, Pend Oreille County, and two others were taken in daytime two miles south of Tenino, Thurston County. However most of the specimens were caught at night.

Long-tailed meadow mice do not, at least ordinarily, make trails as do other meadow mice. Specimens are usually taken unexpectedly, and intensive trapping in the area where a specimen or two is taken rarely yields additional individuals.

Two specimens taken in the Cascade Mountains in September were pregnant; one contained two embryos and the other four.

=Microtus longicaudus halli= Ellerman

_Microtus mordax angustus_ Hall, Univ. California Publ. Zoöl.,
37:13, April 10, 1931 (not of Thomas, 1908).

_Microtus longicaudus angustus_ Goldman, Jour. Mamm., 19:491,
November 14, 1938.

_Microtus mordax halli_ Ellerman, Fam. and Genera of Living
Rodents, British Mus. Nat. Hist., 2:603, March 21, 1941 (new name
for _Microtus mordax angustus_ Hall).

_Type._--Obtained at Godman Springs, 5,700 ft., Blue Mountains,
Columbia County, Washington, by S. H. Lyman, on September 1, 1927;
type in Museum of Vertebrate Zoölogy.

_Racial characters._--Size small; color of sides pale grayish
brown; brown dorsal stripe conspicuous; tail relatively short.

_Measurements._--Four males and 5 females from eastern Washington
average, respectively: total length 164.8, 166.6; length of tail
55.8, 55.8; hind foot 22.0, 21.4.

_Distribution._--From the Blue Mountains of southeastern
Washington north, along the eastern edge of the state, to British
Columbia, and thence west, north of the Columbia River, to the
Cascades, and south along the eastern edge of the Cascades to the
Wenatchee Mountains. Marginal occurrences are: Pasayten River
(Taylor and Shaw, 1929: 24), Hart Lake (Taylor and Shaw, 1929:
24), Blewett Pass (W.W.D.), Boulder Cave (W.W.D.), and Satus Pass
(W.W.D.).

_Remarks._--Four specimens from Satus Pass, Klickitat County, are somewhat intermediate between this race and _macrurus_, and indicate that _halli_ crossed the Columbia River when an alpine meadow land extended from the Simcoe Anticline to southeastern Washington.

One specimen from Selah, Yakima County, is colored somewhat like _halli_, and is smaller than _macrurus_. Possibly the _halli_ type of meadow mouse spread northward to the Yakima Valley. This specimen was taken in the Upper Sonoran Life-zone. A specimen from the Arid Transition Zone at Naches, Yakima County (taken in almost Canadian Life-zone habitat), is like _macrurus-halli_ intergrades from the higher Cascade Mountains.

=Microtus longicaudus macrurus= Merriam

_Microtus macrurus_ Merriam, Proc. Acad. Nat. Sci. Philadelphia, p.
353, October 4, 1898.

_Microtus mordax macrurus_ Dice, Murrelet, 13:49, May, 1932.

_Microtus longicaudus macrurus_ Goldman, Jour. Mamm., 19:491,
November 14, 1938.

_Type._--Obtained at Lake Cushman, Mason County, Washington, by C.
P. Streator on June 26, 1894; type in United States National
Museum.

_Racial characters._--Size large; tail relatively long, almost as
long as head and body; color of upper parts dull brown; dorsal
stripe obscure; underparts gray.

_Measurements._--Two males and 4 females from the Olympic
Mountains and the coast of Washington, average, respectively:
total length 212.5, 220.5; length of tail 82.5, 86.8; hind foot
25.5, 24.7; ear 15.0, 13.7.

_Distribution._--The Olympic Mountains, the coast region of
western Washington, and the Cascade Mountains, save in the
southeastern part. Marginal occurrences are: Sauk (Taylor and
Shaw, 1929: 24), Tye (W.W.D.), Naches River (W.W.D.), and Wind
River (W.W.D.).

_Remarks._--Specimens from the Cascade Mountains are referred to _macrurus_ but are intermediate between that race and _halli_.

=Microtus richardsoni= (De Kay)

Water rat

_Description._--This is the largest meadow mouse found in Washington. It is too large to be called a mouse and the term water rat, applied to it by Merriam, suits it well. It is the only Washington microtine measuring more than 8 inches in total length. The upper parts are dark, reddish brown in color; the underparts are grayish brown. The tail comprises about one-third of the total length.

This species of meadow mouse ranges from Canada south to Colorado in the Rocky Mountains and in the Cascades south into Oregon. The water rats are strictly alpine animals, occurring about streams, marshes and damp meadows. In the Cascade Mountains they are most common in the glacial cirques where tiny streams flow through grassy meadows to plunge over the lip of the cirque on a rocky course of cascades to the valley below. Here their broad trails occur along the stream banks, commonly entering the water where it is swift. These trails are well-worn roads, usually about four inches wide but often wider. The burrows of the water rat are about three inches in diameter and are constructed with no effort at concealment; large mounds of earth mark their entrances. Freshly dug burrows are so abundant that it seems likely more are dug than are actually inhabited. Burrows are often dug beneath rocks.

The water rat is mainly nocturnal but not uncommonly is seen in the daytime. Twice I cornered a water rat away from its burrow and each time it escaped by swimming. The rats swam with great speed but with much splashing. One dived under the surface of a small pool and disappeared. Stones along the bank were pulled out until the rat was captured in a small chamber at the end of a burrow. The burrow entered the bank at the base of a large stone six inches beneath the surface. This burrow resembled a miniature muskrat burrow and apparently had been dug when the rat was under water.

Like _Phenacomys_, the water rat constructs sub-snow nests on the surface of the ground. These are recognizable by their large size and by piles of ovoid droppings a quarter of an inch in length. These nests are loosely built and fall apart soon after the snow melts.

The water rat is sometimes a pest to the mammal collector for they spring mouse traps set for other mammals without becoming caught. At times the greater part of an entire trap line was thus rendered ineffective by these mammals. Fully adult animals are uncommon in collections for a rat trap or steel trap is needed to take them and these items, when packed on back up mountains to water-rat habitat, are usually set for still larger animals. Racey (Racey and Cowan, 1935: H27) recounting his difficulty in securing specimens when no suitable traps were at hand, writes: "Killed one with my hands, shot another, and a third was stunned by a mouse trap."

Taylor and Shaw (1927: 76) list food eaten by the water rat on Mount Rainier as the avalanche lily, dogtooth violet, _Ligusticum purpureum_, _Valeriana sitchensis_, _Polygonum bistortoides_, _Petasites frigida_, _Phyllodoce empetriformis_, _Potentilla flabellifolia_, _Aster_ sp., grass, wild clover, conifer seeds, two kinds of blueberry (_Vacinnium_) and _Xerophyllum tenax_. Racey and Cowan (1935) list foods eaten in the Cascades of southern British Columbia as _Lupinus polyphyllus_, _Senecio balsamitae_, _Pedicularis bractiosa_ and _Arnica alpinus_.

A female from Dewey Lake, Yakima County, contained 4 embryos on September 1, 1940. One from Tye, King County, had 2 embryos on September 8, 1940.

=Microtus richardsoni arvicoloides= (Rhoads)

_Aulacomys arvicoloides_ Rhoads, Amer. Nat., 28:182, February,
1894.

_Microtus richardsoni arvicoloides_ Bailey, N. Amer. Fauna, 17:62,
June 6, 1900.

_Type._--Obtained at Lake Keechelus, Kittitas County, Washington,
by A. Rupert in September, 1893. Rhoads gives the altitude as 8,000
ft. This apparently is an error, for the elevation of the lake is
2,458 ft. and the summit of Snoqualmie Pass, to the west, is 3,100
ft. Probably 3,000 ft. was intended; type in Philadelphia Academy
of Natural Sciences.

_Racial characters._--Size large; color of upper parts dark
reddish brown; underparts paler.

_Measurements._--A female from Tomyhoi Lake, Whatcom County,
measured: total length 242; length of tail 68; hind foot 27; ear
17. A female from Tye, King County, measured: 257; 83; 26; 17.

_Distribution._--The Cascade Mountains, from Tomyhoi Lake (W.W.D.)
south to Potato Hill (Taylor and Shaw, 1929: 25).

=Microtus richardsoni macropus= (Merriam)

_Arvicola (Mynomes) macropus_ Merriam, N. Amer. Fauna, 5:60, July
30, 1891.

_Microtus richardsoni macropus_ Bailey, N. Amer. Fauna, 17:61,
June 6, 1900.

_Microtus richardsonii macropus_ Taylor and Shaw, Occ. Pap. Chas.
R. Conner Mus., no. 2:25, December, 1929.

_Type._--Obtained in the Pashimeroi Mountains, 9,700 ft., Custer
County, Idaho, by C. H. Merriam and V. Bailey in 1890; type in
United States National Museum.

_Racial characters._--Similar to _arvicoloides_ but slightly
smaller and redder.

_Measurements._--A female from Stay-a-while Spring, Columbia
County, measures: total length 228; length of tail 73; hind foot
25; ear 14.

_Distribution._--The Blue Mountains of southeastern Washington.

=Microtus oregoni oregoni= (Bachman)

Creeping mouse

_Arvicola oregoni_ Bachman, Jour. Acad. Nat. Sci. Philadelphia,
8:60, 1839.

_Microtus oregoni_ Miller, N. Amer. Fauna, 12:9, July 23, 1896.

_Microtus morosus_ Elliot, Field Columb. Mus. Publ. 30, zoöl.
ser., 1:227, February 1, 1899 (type from Boulder Lake, 5,000 ft.,
Clallam County, Washington).