Walter Woelber Dalquest

“ The Columbia River in its course westward through the Cascade Mountains, might be expected to act as a highway for the movement of mammals, but the extent to which it has done so seems to be slight, at least in postglacial time. The pocket gopher of southwestern Washington reached the area about Vancouver from the southern Cascades by way of meadows on the gravel terraces of Wisconsin glacial drift. No other mammal seems to have extended this far. Several Great Basin species, such as the cottontail, extend westward in the valley of the Columbia to the vicinity of Bingen. ”

“ It is difficult to see how the tiny ermine could kill an adult mountain beaver, which outweighs it many times. Should the incisors of the mountain beaver close even once upon an ermine it would most certainly be seriously wounded or killed. Judging by the forest habitat occupied by the ermine in [Pg 191] Washington, one might expect its principal food to consist of deer mice (Peromyscus maniculatus) , red-backed mice (Clethrionomys) and meadow mice (Microtus) .
In observing the activities and habits of mammals in their natural habitat, I have often relied on tracking in fresh snow. ”

“ 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. ”

“ The mammals that are racially distinct on the two sides of the Columbia River merit careful scrutiny. The Peromyscus of the two sides more closely resemble one another than those of southern Oregon resemble those of northern Oregon or than those of southern Washington resemble those of northern Washington. For Peromyscus maniculatus, the Columbia River is simply a convenient boundary for the separation of two slightly different races. The Oregon race of the bushy-tailed wood rat is a coastal type but the Washington form is the same as that of eastern Washington. ”

“ The elk is a browsing animal, feeding on twigs and leaves of deciduous trees, shrubs and evergreens. In spring and summer it eats grasses and succulent annuals, but in winter twigs and needles of evergreens, perennial ferns, dry grass and even moss is utilized. To a certain extent the elk are migratory, ascending to the open meadows of the Hudsonian Life-zone in the early summer and returning to the dense forests of the Transition and lower Canadian Life-zones with the winter snows. ”

“ Mountain goats are considered a game animal in Canada and Idaho. The species has been protected in Washington for many years. As a result they are common, although not present in numbers sufficient to withstand hunting. The high country which they occupy is unsuited to any of man's domestic animals and no reason is apparent at present why the mountain goat should not be protected and conserved for many years. ”

“ The black bear is omnivorous in the truest sense of the word. Because the animal is of large size it requires much nourishment. This is obtained by eating large quantities of material with low food value. Material eaten passes rapidly through the digestive tract and often only easily digested parts seem to be utilized. Feces commonly contain complete and undigested berries and seeds or almost undigested pieces of apples or other fruit.
The principal food of the black bear in Washington is berries. Many species are eaten, but the huckleberry (Vaccinium sp.) is favored. ”

“ In Washington pikas live only in talus slides and rock piles, where they find refuge from most of the carnivores that prey on small mammals. Their distribution in the state seems to be regulated by the distribution of talus slides, and areas free of talus act as effective barriers to pikas. They are abundant throughout the Cascades but are absent from the Olympic Mountains although conditions there are well suited to them. Probably the lowlands of western Washington which, owing to moderate temperature and low relief, have little talus and exposed rock, serve as a barrier. ”

“ The Arid Grasslands Subdivision of the Transition Life-zone This subdivision is so much utilized by man where it occupies any considerable areas, and is of such a transitional nature elsewhere, that it is important for only a few native wild mammals. The sagebrush vole (Lagurus curtatus) seems to be confined to the arid grasslands. The white-tailed jack rabbit is now found principally in the arid grasslands, but its confinement there has resulted probably from competition with the black-tailed jack rabbit. The montane meadow mouse (Microtus montanus) is the only common, representative species. ”

“ Remarks.—The moose is the largest North American deer. Its large size and huge, palmate antlers serve to separate it from any other member of the deer tribe.
Moose range from northern United States to central Canada and Alaska. The European elk and the American moose are subspecies of the same species. The moose is of only casual occurrence in Washington. The latest authentic record for Washington is a bull that wandered southward and westward from Canada until it was killed on an Indian reservation in Ferry County. ”

“ At least in the breeding season the gophers work mainly and make their nest where the soil is deepest. In the vicinity of this nest, considerable mounding and cultivation of soil ensues. This stimulates plant growth in the area. Much observation indicates that cultivation of earth by gophers stimulates plant growth to a greater extent than the depredations of the gopher deplete the ensuing growth. Thus the gopher, by cultivation of the soil in the area about its burrow, stimulates the growth of vegetation and so increases his own food supply. ”

“ In examining badger workings in ground squirrel colonies I have been impressed by the fact that most of the holes ended not more than four or five feet from the entrances—perhaps at the places where the ground squirrel nests were located, although it may be that the digging of the badger so terrified the squirrels that they dashed out in an attempt to escape past the badger, before he reached the nests. Kangaroo rats and pocket mice often attempt to escape by dashing past a person when he is excavating their burrows. ”

“ On Vancouver Island, British Columbia, a short-tailed, austerus-type [Pg 97] of mouse occurs in the lowlands and a long-tailed, oreas-type of mouse in the mountains. Vancouver Island is a large island (16,400 square miles) . Apparently a stock of austerus from the mainland reached Vancouver Island and were able to find suitable habitat and compete with and drive out the established oreas in the manner that they probably did in the western Washington lowlands. ”

“ Jumping mice are of rather general distribution in Washington, being only locally common. They are partial to damp, boggy areas but avoid true swamps. They occur in clearings in the forests in the Puget Sound area and in meadows in river bottoms and in jungles in ravines. They reach their greatest abundance in the boggy meadows and glacial cirques of the mountains and spread out from such areas to seemingly less favored habitat on dryer slopes and heather meadows. Unlike many species, they do not seem to inhabit talus slides. They are entirely absent from the eastern Washington desert. ”

“ Inherent variability is another thing that has to be taken into account when considering the differentiation of the mammals of Washington into subspecies. The pocket gopher is an extremely plastic species, especially in Washington, whereas the Douglas squirrel is less so. The flying squirrels, the yellow-pine chipmunk and the snowshoe rabbit are the other plastic species. These species are not so likely to break up into numerous subspecies over all of their ranges as they are in Washington where [Pg 70] in a small area the topography is highly varied. ”

“ 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. ”

“ The pocket gopher is principally nocturnal or crepuscular but sometimes it is active at midday, especially if the day be dark and cloudy. Pocket-gopher activity is indicated by fresh mounds of earth on the surface of the ground. Rarely, an observer may see movement of plants as the gopher molests the roots of the plants, or even see the head and shoulders of an animal that partly emerges from an open burrow. The ordinary gopher mound consists of less than a cubic foot of earth. The earth is forced up from a single opening and usually is pushed out in one direction. ”

“ In the northwestern Cascades of northern Washington and southern British Columbia, a richly-colored race, T. a. felix, now occupies a limited geographic range. This race doubtless originated from ludibundus stock but the method of its development is unknown. Perhaps in early postglacial time, selective factors developed in chipmunks of the western slopes of the Cascade Mountains the rich, dark color of felix. The ancestral ludibundus may have given rise to a pale race, affinis, in the arid eastern Cascades and a dark race, felix, on the humid western slope of the Cascades. ”

“ In suitable habitat the surface of the ground beneath the grass is a maze of these tunnels, which cross, intersect, and divide in a complex network. An observer standing in a field occupied by creeping mice can scarcely conceive of the extent and perfection of the tiny tunnel system at his feet.
Creeping mice lived but a day or two in captivity. Save for the bits of grass blades left in their runways, little is known of their food or other life habits. Their nests are round balls of dry grasses placed in cavities under logs. ”

“ The habitat of the Columbian ground squirrel is varied but is usually more humid than that of the Townsend and Washington ground squirrels. The most arid of the lands occupied by them in Washington are the grasslands and wheat fields of the Poulouse country and the eastern border of the state. In northeastern Washington they live in meadows and grasslands in the valleys, in openings in the coniferous forest at higher altitudes and in parks and alpine meadows almost to timber-line on the mountains. ”

“ During this time, forest mammals of the Pacific Coast were isolated from forest mammals farther east by glaciers to the north and desert to the east. Changes took place in both of the separated forest faunas. Certain species, perhaps, such as the mammoth, became extinct. Other forms were exterminated then or at an earlier time in one fauna or the other. If Aplodontia, Neurotrichus or Scapanus occurred in the Rocky Mountain faunal area, it lived in an inland area of rigorous climate, and disappeared there because it was unable to adapt itself to the cold. ”

“ The blacktail lives in some of the most dense jungle areas of western Washington. On Whidby Island and some of the San Juan Islands the brush and vines grow so densely that a man can scarcely penetrate them. Were it not for the deer trails, formed by generations of deer, our small mammal investigations would have been far more difficult. The blacktail lives also in the dense forests where fir, hemlock and cedars grow to heights of more than 150 feet. Here lack of light allows only ferns and moss to form an understory vegetation. ”

“ 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. ”