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."
[Illustration: FIG. 110. Distribution of the heather vole in
Washington. A. _Phenacomys intermedius oramontis._ B. _Phenacomys
intermedius intermedius._]
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.
[Illustration: FIG. 111. Distribution of the Gapper and California
red-backed mice in Washington. A. _Clethrionomys gapperi saturatus._
B. _Clethrionomys gapperi idahoensis._ C. _Clethrionomys gapperi
nivarius._ D. _Clethrionomys gapperi cascadensis._ E. _Clethrionomys
californicus occidentalis._]
=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.
[Illustration: FIG. 112. Pennsylvania meadow mouse (_Microtus
pennsylvanicus kincaidi_), from ten miles south of Moses Lake,
Washington, April 28, 1940. (Fish and Wildlife Service photo by Victor
B. Scheffer, No. 937.)]
_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.
[Illustration: FIG. 113. Distribution of the Pennsylvania meadow mouse
in Washington. A. _Microtus pennsylvanicus funebris._ B. _Microtus
pennsylvanicus kincaidi._]
=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.
[Illustration: FIG. 114. Distribution of the montane and Townsend
meadow mice in Washington. A. _Microtus montanus nanus._ B. _Microtus
montanus canescens._ C. _Microtus townsendii townsendii._ D. _Microtus
townsendii pugeti._]
_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.
[Illustration: FIG. 115. Runways of Townsend meadow mice (_Microtus
townsendii_) worn to grooves in the damp soil at Seattle; May 18,
1938; dense cover of cattails has been burned off (W. W. Dalquest
photo).]
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)