1936] MAMMALS OF OREGON 365 



leaves and the surface of the ground or occupy burrows of meadow 

 mice and other rodents, or the hollow banks and ridges along 

 streams and gulches. They are often caught in traps set in runways 

 of meadow mice, or at holes made by other small animals, sometimes 

 by accident as they run across the trap triggers and sometimes while 

 eating the bait prepared for them or for other species. They appear 

 to be as active and as often caught in daytime as at night, and are 

 abroad throughout the year. 



Breeding habits. The regular number of mammae in breeding 

 females is 2 pairs of inguinal and 1 pair of abdominal, and the 

 number of embryos found in females trapped for specimens varies 

 from 5 to 7. At Crescent City, Calif., W. K. Fisher took 2 females 

 on July 5, each containing 6 embryos. At McKenzie Bridge Luther 

 Goldman took 1 on July 2 containing 7, and at Crater Lake on 

 August 14 a female was taken with 6 embryos. The uniformity of 

 the dates and the comparatively few records of embryos would in- 

 dicate but one litter of young a year. 



Food habits. Field examination of stomachs usually shows traces 

 of insect remains, well masticated and unidentifiable by superficial 

 methods. Apparently soft-bodied larvae and eggs, worms, and 

 other small earth-dwelling animal forms are included in the bill of 

 fare. Occasionally traces of animal flesh are found in the stomachs, 

 either from trap bait or from trapped animals which they frequently 

 devour. They are often caught in traps baited with rolled oats or 

 nut meats, and a trace of these foods is sometimes found in their 

 mouths or stomachs, but vegetable food seems not to be commonly 

 eaten. Digestion is evidently rapid, and the stomachs are often 

 found empty while the food has all passed along to the intestines. 



Economic status. If, like other shrews, these little fellows eat 

 almost continuously, and consume twice their weight of insects, lar- 

 vae, and eggs every 24 hours, they might well fill a very important 

 place in the economy of nature, a place comparable with that of 

 the wrens, warblers, or hummers among birds. Fortunately they 

 are unpleasantly musky and seem not to be generally relished by 

 carnivorous birds or mammals and with their habits of seclusion 

 are in little danger. 



SOREX VAGRANS MONTICOLA MEEBIAM 

 ROCKY MOUNTAIN SHREW 



Sorex monticola Merriam, North Amer. Fauna No. 3, p. 43, 1890. 



Type. Collected on San Francisco Mountain, Ariz., 11,500 feet altitude, Au- 

 gust 28, 1889, by C. Hart Merriam and Vernon Bailey. 



General characters. Small, summer pelage short. Similar to vagrans in 

 size and general appearance, but color more grayish brown; upper parts in 

 summer pale sepia brown, lower parts ashy gray; tail brownish above, whitish 

 beneath except at the dark tip. 



Measurements. Average of four specimens from type, locality : Total length, 

 108 mm ; tail, 44 ; foot, 12-13. Type, male adult : 107 ; 45 ; 12.5. 



Distribution and habitat. Kocky Mountain region from southern 

 British Columbia to Mexico and westward over eastern Washington 

 and Oregon (fig. 89). They are the commonest little shrews of the 

 Blue Mountains and Steens Mountains in Canadian Zone, and often 



