Specimens examined.—Total number, 20, arranged by counties from north to south. Unless otherwise indicated, specimens are in the U. S. National Museum.
Washington. Clallam County: Clallam Bay, 2 (1[74], 1[94]); Elwha, 2[10]; Johnsons Ranch, 1[60]; Happy Lake, 1[60]; Boulder Lake, 2[60]; near head of Soleduc River, 4500 ft., 1; 12 mi. S Port Angeles, 1[10]. Jefferson County: Hayes Cr., 2000 ft., Elwha River, 2; head N Fork Quinault River, 4000 ft., 1; Duckabush, 3; N Fork Skokomish River, 1. Mason County: Lake Cushman, 2[76]; 4 mi. S Olympia, 1.
Mustela erminea streatori (Merriam)
Ermine
Plates [5], [6], [7], [12], [13] and [14]
Putorius streatori, Merriam, N. Amer. Fauna, 11:13, pl. 2, figs. 5, 5a, 6, 6a, June 30, 1896.
Putorius cicognanii, Baird, Mamm. N. Amer., p. 161, 1858 (part unless no. 2395 was a female of M. frenata).
Putorius pusillus, Baird, Mamm. N. Amer., p. 159, 1858 (part).
Putorius (Gale) vulgaris, Coues, Fur-bearing animals, p. 102, 1877 (part).
Mustela streatori streatori, Miller, U. S. Nat. Mus. Bull., 79:96, December 31, 1912; Grinnell, Univ. California Publ. Zoöl., 40:101, September 26, 1933.
Mustela cicognanii streatori, Hall, Murrelet, 12:22, January, 1931; Hall, Univ. California Publ. Zoöl., 38:417, November 8, 1932.
Mustela erminea streatori, Hall, Journ. Mamm., 26:77, February 27, 1945; Hall, Journ. Mamm., 26:181, July 19, 1945.
Mustela rixosa, Beer, Journ. Mamm., 29:296, August 31, 1948.
Type.—Male, adult, skull and skin; no. 76646, U. S. Nat. Mus., Biol. Surv. Coll.; Mount Vernon, Skagit Valley, Skagit County, Washington; February 29, 1896; obtained by D. R. Luckey, original no. 3.
The skull is unbroken and the teeth all are present and entire. The skin, in brown winter pelage, is stuffed and in good condition.
Range.—Western Washington along eastern side of Puget Sound, western Oregon from the Cascades to the coast, and northwestern California south in the humid coastal district nearly to the Golden Gate. See figures [25], [27] on pages 95, 149.
Characters for ready recognition.—Differs from M. e. anguinae, in male, by sagittal crest present and hind foot ordinarily less than 33.5, in female by hind foot less than 27.5, basilar length less than 30.2; from M. e. fallenda, in both sexes, by black tip of tail less than half of length of tail-vertebrae, in males hind foot less than 33.7, tympanic bulla about same length as, instead of longer than, upper tooth-rows; weight of skull less than 1-1/4 grams, in female weight of skull less than 0.7 grams, length of lateral side of P4 less than 4 mm.; from M. e. olympica, by larger size, in males hind foot more than 33.0, basilar length ordinarily more than 32.5, in females by hind foot ordinarily longer than 24, by breadth of rostrum more than 8.6, depth of braincase at posterior border of upper molars more than 7.6; from M. e. gulosa and muricus, in both sexes, by upper lips brown (not white), light color of underparts extending down hind leg no farther than knee, depth of skull at posterior border of upper molars more than 7.7 in females and ordinarily more than 9.6 in males, further from muricus by tail more than 62 in males and more than 49 in females; from M. e. invicta by upper lips white (not brown), in males hind foot more than 36 and basilar length more than 35, in females hind foot more than 29.5 and basilar length more than 30.5.
Description.—Size.—Male: Twelve adults from Blaine and Tillamook, Oregon, yield average and extreme measurements as follows: Total length, 255 (245-275); length of tail, 72 (64-80); length of hind foot, 31.5 (30.0-33.5).
Female: Seven adults from Blaine and Tillamook, Oregon, yield average and extreme measurements as follows: Total length, 214 (193-230); length of tail, 55 (50-63); length of hind foot, 25 (24-27).
Color.—Winter and summer pelages indistinguishable; upper parts uniform and ranging from Raw Umber to slightly darker (16n), and about tones 1 to 3 of Dark Chocolate of Oberthür and Dauthenay, pl. 342; underparts white, in summer rarely with a faint buffy suffusion in pectoral region; color of underparts extends from chin, and often lower lips, posteriorly to inguinal region, distally on posterior sides of forelegs onto antipalmar faces of toes (sometimes interrupted at and above wrist) and on medial sides of hind legs hardly to knee. Least width of color of underparts averaging, in twelve adults from Blaine and Tillamook, 10 (0-47) per cent of greatest width of color of upper parts. Black tip of tail, in same series, averaging 28 (24-33) mm. which is 40 (34-47) per cent of length of tail-vertebrae.
Skull.—Male (based on 12 adults): See measurements and plates [5]-[7]. As described in Mustela erminea richardsonii except that: Weight, 1.1 (1.0-1.2) grams; basilar length, 33.2 (32.5-33.8); length of tooth-rows more or less than (about same as) length of tympanic bulla.
Female (based on 7 adults): See measurements and plates [12]-[14]. As described in Mustela erminea richardsonii except that: Weight, 0.64 (0.60-0.67) grams; basilar length, 28.5 (27.6-29.5); breadth of rostrum more than 30 per cent of basilar length.
Comparison with anguinae, fallenda, olympica, gulosa and muricus is made in accounts of those subspecies.
Remarks.—This weasel is rare in collections and the best material of it was obtained by Alex Walker in Tillamook County, Oregon, where he resides. The almost ideal series of 30 specimens showed the range of secondary sexual, age, and individual variation expectable in the small ermines of the Pacific Coast of the United States and was the means of allowing satisfactory decision on questions of classification in the related subspecies in which individuals are of comparable size.
Intergradation with each of the geographically adjoining subspecies, olympica, fallenda, invicta, gulosa and muricus is shown by specimens examined. With the last mentioned subspecies, intergradation is shown by two specimens from as far south as Siskiyou County, California, assigned to muricus.