2IO ECONOMIC MAMMALOGY 



mal this vole was reduced to insignificance in the course of a few weeks, 

 while all other kinds of mice had suffered severely from the same en- 

 emy. . . . All our weasels are eminently mousers, but it is the least weasel 

 that is the natural enemy of Microtus minor, being so small it can read- 

 ily follow the rodents through their runways into their homes." 19 A den 

 of the least weasel examined by Winecoff contained "remains of mice 

 only, not a hint of a feather." 20 



Streator weasels (Mustela streatori streatori) were found to be "liv- 

 ing on conies [pikas] and different species of mice," and stomachs of 

 Washington weasels (M. washingtoni) contained remains of gophers, 

 red-backed mice, deer mice, pikas, squirrels and a junco. 21 The dwarf 

 weasel (Mustela streatori leptus), confined mostly to high altitudes in 

 the Rocky Mountains, is supposed to eat "conies" or pikas and mice. 22 

 La Valette says that weasels are enemies of fish, 23 but that enmity 

 cannot be considered serious. Kirk says that weasels do not eat trapped 

 shrews and shrews do not eat trapped weasels, 24 which does not neces- 

 sarily mean that Coues was mistaken in listing Insectivora as part of 

 the diet of weasels under natural conditions. Hamilton definitely re- 

 ports two shrews contained in weasel stomachs and says weasels are 

 often seen carrying dead shrews. 25 



The ticks carried by weasels are not known to be harmful to human 

 beings, but, on the other hand, the weasels may do some good by killing 

 rodents which are hosts of the spotted fever tick. 26 



The black-footed ferret (Mustela nigripes), found about prairie-dog 

 "towns" or colonies on western plains, feeds mostly upon prairie-dogs, 

 whose burrows it may easily enter, and is sometimes called the prairie- 

 dog ferret, though it is too scarce to have much economic value. 27 Euro- 

 pean ferrets (Mustela put onus) eat many small rodents, and have been 

 reared in captivity and trained to catch rats and rabbits by entering their 

 burrows. 



19 Criddle, Journ. Mammalogy, vn, 199-200, 1926. 



20 Winecoff, Least weasel in captivity, Journ. Mammalogy, xi, 312-313, 1930. 



21 Taylor and Shaw, Mammals and birds of Mount Rainier National Park, pp. 

 52, 53, 1927. 



22 Gary, N. Amer. Fauna, No. 33, p. 187, 1911. Dixon, Journ. Mammalogy, xn, 



72, 1931- 



23 LaValette, Kept. U. S. Fish Comm. for 1878, pp. 509-516. 



24 Kirk, Shrews and weasels, Journ. Mammalogy, n, in, 1921. 



25 Hamilton, Weasels eat shrews, Journ. Mammalogy, ix, 249, 1928. 



26 Birdseye, Farmers' Bull., No. 484, 1912. 



27 Gary, AT Amer. Fauna, No. 33, p. 184, 1911. Bailey, N. Amer. Fauna, No. 49, 

 p. 171, 1926. Seton, Lives of game animals, n, Part 2, pp. 566-574, 1929. Nelson, 

 Wild animals of North America, p. 571, 1918. 



