Part 11

Remarks.--This subspecies is transitional between the large, usually dark subspecies of the southeastern Alaskan and British Columbian coast and islands, and the smaller, paler subspecies of western and interior Alaska. There seem to be no sharp breaks between alascensis and shumaginesis. North of Haines, Alaska, size of shrews decreases in a short distance across a narrow intergradational zone between alascensis and obscurus. Throughout most of its range S. v. alascensis occurs with Sorex cinereus.

Specimens examined.--Total number, 88.

ALASKA: Orca, 1 BS; Montague Island, Prince William Sound, 2 BS; Yakutat, 8 BS; north shore Yakutat Bay, 2 BS; Yakutat Bay, 1 BS; E side Chilkat River, 100 ft., 9 mi. W and 4 mi. N Haines, 12 KU; 1 mi. S Haines, 5 ft., 10 KU; 7 mi. SSE Haines, 10 ft., 2 KU; N end Sullivan Island, 10 ft., 6 KU; SE end Sullivan Island, 10 ft., 2 KU; Glacier Bay, 3 BS; Mendenhall River, 1 BS; Juneau, 36 BS.

BRITISH COLUMBIA: Sheslay River, 1 AMNH; headwaters Sheslay River, 1 AMNH.

Marginal Records.--ALASKA: Valdez Narrows, Prince William Sound (Jackson, 1928:128); north shore Yakutat Bay; east side Chilkat River, 100 ft., 9 mi. W and 4 mi. N Haines. BRITISH COLUMBIA: Sheslay River (Jackson, 1928:128). ALASKA: Juneau; Glacier Bay; Montague Island, Prince William Sound (ibid.); Port Nell Juan (ibid.).

=Sorex vagrans shumaginensis= Merriam

Sorex alascensis shumaginensis Merriam, Proc. Washington Acad. Sci., 2:18, March 14, 1900.

Sorex obscurus shumaginensis, Allen, Bull. American Mus. Nat. Hist., 16:228, July 12, 1902.

Type.--Adult male, skin and skull; No. 97993, U. S. Biol. Surv. Coll.; obtained on July 17, 1899, by De Alton Saunders from Popof Island, Shumagin Islands, Alaska. (Measured by C. Hart Merriam and numbered 2210 in A. K. Fisher's catalog.)

Range.--Southwestern Alaska from Seward Peninsula southeasterly to western part of Kenai Peninsula and southwesterly to the southwestern end of the Alaskan Peninsula.

Diagnosis.--Size medium to small for the species; average and extreme measurements of 6 specimens from King Cove, Alaska, are: total length, 112.7 (107-118); tail, 48.3 (45-52); hind foot, 13.8 (13-14). Tending toward the development of a tricolor pattern, the back darkest, the sides buffy, and the venter paler.

Comparisons.--Paler and more definitely tricolored than S. v. obscurus; also with relatively shorter palate, narrower rostrum and smaller teeth. For comparison with S. v. alascensis see account of that subspecies.

Remarks.--S. v. shumaginensis occurs together with Sorex cinereus over much of southwestern Alaska. Part of the range of shumaginensis falls within the tundra of the Arctic Life-zone. This may be a partial explanation of the tricolored pattern of the animal. Sorex tundrensis, S. cinereus ugyunak, and S. cinereus haydeni, shrews which dwell mostly in treeless areas, are markedly tricolored, or bicolored. Sorex arcticus, however, although tricolored, is found in forested areas.

Specimens examined.--Total number, 340. ALASKA: Sawtooth Mts., Nome River, 2 AMNH; Nulato, 5 BS; St. Michaels, 1 BS; Bethel, 7 BS; Aniak, 1 BS; Skeventna River, 1 BS; 6 mi. WSW Snowshoe Lake, 1 KU; 1 mi. NE Anchorage, 1 KU; Tyonek River, 48 BS; Hope, 15 BS; Hope, Mts. near, 13 BS; Moose Camp, 3 AMNH; Kenai Peninsula, 24 AMNH; Kakwok River, 80 mi. up, 1 BS; Kakhtul River, 5 BS; Kakwok, 3 BS; Goodnews Bay, 1 BS; Lake Aleknagik, 6 BS; Nushagak River, 25 mi. above Nushagak, 1 BS; Dillingham, 1 BS; Nushagak Village, 15 BS; Homer, 1 AMNH; Kenai Mts., 37 AMNH; Seldovia, 24 AMNH; Barabor, 1 AMNH; Caribou Camp, 7 AMNH; Ugagik River, 3 BS; Becharof Lake, 8 BS; Cold Bay, 14 BS; Kanatak, Portgage Bay, 4 BS; Chignik, 6 BS; Moller Bay, 1 BS; Alaska Peninsula, near Popof Island, 6 AMNH; Frosty Peak, 15 BS; Morzhovoi Bay, 7 BS; Ungu Island, 3 BS; Sand Point, Popof Island, 45 AMNH; Popof Island, 3 BS.

Marginal Records.--ALASKA: Nome River; Nulato; Kuskokwim River, 200 mi. above Bethel, Crooked Creek (Jackson, 1928:126); 6 mi. WSW Snowshoe Lake; Seldovia; mts. near Hope; Morhzovoi Bay; thence along coast to St. Michael.

=Sorex vagrans obscurus= Merriam

Sorex vagrans similis Merriam, N. Amer. Fauna, 5:34, July 31, 1891, nec. S. similis Hensel, Zeitschr. der Deutsch. Geolog. Gesellsch., 7:459, 1855 (= Neomys similis).

Sorex obscurus Merriam, N. Amer. Fauna, 10:72, December 31, 1895, new name for Sorex vagrans similis Merriam.

Sorex obscurus obscurus, Miller, Bull. U. S. Nat. Mus., 79:15, December 31, 1912.

Type.--Adult female, skin and skull; No. 23525/30943, U. S. Biol. Surv. Coll.; obtained on August 26, 1890, by Vernon Bailey and B. H. Dutcher from near Timber Creek, 8200 ft., Lemhi Mts., 10 mi. SSW Junction (now Leadore), Lemhi Co., Idaho.

Range.--Mountainous interior of western North America from central Alaska east across Yukon and southwestern Northwest Territories to northeastern Alberta, south in the mountains through north-central and western Washington, Idaho, western Montana, Wyoming, Utah, and Colorado, into northern New Mexico.

Diagnosis.--Size medium to small for the species; average and extreme measurements of 9 topotypes are: total length, 110.3 (105-117); tail, 46.4 (42-50); hind foot, 13.1 (12.5-13.5). Color grayish or brownish gray in summer, light grayish in winter.

Comparisons.--For comparisons with S. v. setosus, S. v. longicauda, S. v. alascensis and S. v. shumaginensis see accounts of those subspecies. Paler and slightly larger than S. v. soperi. Larger than the subspecies from central Montana herein described as new. Smaller than S. v. neomexicanus. Averaging larger in all dimensions than S. v. monticola with which obscurus intergrades in northern New Mexico and northern Arizona. Larger than S. v. vagrans with more grayish rather than reddish fresh summer pelage and light gray rather than dark grayish-black fresh winter pelage.

Remarks.--Intergradation of S. v. obscurus with S. v. setosus, S. v. longicauda, S. v. alascensis, and the new subspecies from Montana takes place in the usual way with specimens from intermediate localities being intermediate in size and color. However the relationship of S. v. obscurus and S. v. vagrans (as the latter subspecies is defined in this study) is rather complicated. In southern British Columbia where the two subspecies come together a situation of remarkable complexity prevails. Series from some localities seem to represent intergrades between obscurus and vagrans; from other localities some specimens seem to be referable to one and some to the other subspecies; from other localities all specimens seem referable to one subspecies. A similar situation is seen in specimens from northeastern Washington, northern and central Idaho, and extreme western Montana. The region mentioned is one of extensive interfingering of life-zones. In southern British Columbia the main axes of the rivers, valleys and mountain ranges are north and south. Most of the valleys are in the Transition Life-zone; the forests are rather dry and of pine with more or less isolated hydrosere communities about streams and ponds. These hydrosere situations are the habitat of Sorex vagrans. Shrews from these situations are usually referable to vagrans. The high ridges and mountain ranges are usually in the Canadian Life-zone or higher and most of the shrews referable to obscurus come from such places. Marginal localities with regard to life-zone produce most of the populations which seem to represent intergrades between the two subspecies. Isolated areas of Canadian Life-zone, even though surrounded with Transition Life-zone, often harbor a population of obscurus, whereas the streams in the nearby dry valleys harbor populations of vagrans. Farther south in the Rocky Mountain chain, obscurus seemingly intergrades regularly with vagrans. This intergradation is seen in populations from several localities in Utah. There the lower elevations west of the Wasatch and Uinta mountains are inhabited by S. v. vagrans, the higher elevations by obscurus and where the ranges of the two abut intergrading populations occur. In these series of intergrades there are specimens which, using size as a subspecific criterion, would unhesitatingly be assigned, as individuals, to obscurus, and others would be assigned to vagrans, but these individuals represent extremes of a normally variable population. At Cuddy Mountain, Idaho, the two subspecies seemingly abut without intergradation; anyhow the available specimens from this locality are referable to one or the other subspecies and none is intermediate. The situation just described understandably has been the source of much anguish to students who sought to identify shrews from the Rocky Mountains. The reason for the relationship just described has been discussed at length in a previous section.

In the Rocky Mountains of Wyoming and Colorado the subspecies S. v. obscurus ranges almost uninterruptedly over relatively large areas, but southward in New Mexico and southwestward into Utah and Arizona, suitable boreal habitat becomes insular in nature and obscurus there is confined to the higher mountains. With one exception, once the shrew populations become 'insular' in this region they become smaller and show intergradation with Sorex vagrans monticola. The exception is the population in the Sacramento Mountains of southeastern New Mexico which is larger than obscurus and has been rightly recognized as a distinct subspecies, neomexicanus.

Almost without exception the range of typical Sorex vagrans obscurus is sympatric with that of Sorex cinereus, usually the subspecies S. c. cinereus. So close is this correspondence that the presence of S. cinereus comes near to being a useful aid in identifying S. v. obscurus. In areas where individuals of obscurus show intergradation with vagrans, Sorex cinereus is absent or rare. The implication is that as the species S. vagrans approaches the size of the species S. cinereus, competition between the two increases with resultant displacement of cinereus.

Specimens examined.--Total number, 982.

ALASKA: Wahoo Lake, 69 deg. 08' N, 146 deg. 58' W, 2350 ft., 2 KU; Chandler Lake, 68 deg. 12' N, 152 deg. 45' W, 2900 ft., 1 KU; Bettles, 1 KU, 5 BS; Alatna, 1 BS; Yukon River, 20 mi. above Circle, 1 BS; Tanana, 1 BS; Mountains near Eagle, 18 BS; Richardson, 8 BS; head of Toklat River, 11 BS; Savage River, 8 BS.