MAMMAL ENEMIES OF MICE. 39 



The chief natural enemies of field mice are (1) mammals, wild 

 and domestic, (2) birds, and (3) snakes. 



Mammals That Destroy Field Mice, 

 wild mammals. 



Among the wild mammals of the United States known to feed 

 upon field mice are wolves, lynxes, foxes, badgers, raccoons, opos- 

 sums, skunks, weasels, and shrews. A few of these feed npon mice 

 habitually, and this habit, combined with their well-known service 

 in destroying insects, compensates in great measure for the injuries 

 they inflict in other ways. 



Skunks are efficient in the destruction of mice and rats. The 

 larger skunks (Mephitis), with about 17 species and subspecies, are 

 distributed over most of the territory occupied by field mice. Their 

 chief food is insects, but mice are second in importance on the bill of 

 fare. Skunks not only search woods and meadows for mice but 

 often come about barns and outbuildings in quest of the common 

 mouse" . (Mus musculus) and brown rat (Mus norvegicus). While 

 it is true that skunks sometimes destroy poultry, they do so much 

 less frequently than is generally supposed. Comparatively few 

 skunks learn to kill chickens, the habit being characteristic of the 

 individual rather than of the species. 



Of 36 skunks of the genus Mephitis Avhose stomachs were examined 

 by the Biological Survey, two only, both captured in poultry houses, 

 had eaten domestic fowls. There was no evidence that any of the 

 36 had destroyed game or small birds. The food consisted princi- 

 pally of beetles, grasshoppers, cicadas, crickets, rats, mice, and liz- 

 ards. On account of their usefulness in destroying noxious insects 

 and rodents, skunks deserve even more than the partial protection 

 now afforded them by the laws of several States. 



The habits of the little spotted skunks (Spilogale) are similar to 

 those of the larger species. Like them, they are useful because they 

 destroy insects and mice. Occasionally individuals learn to destroy 

 domestic fowls, but the habit is even rarer than with the large skunks. 

 As persistent and successful mousers about farm premises, they are 

 unequaled and should be protected, the death penalty being reserved 

 solely for the individuals that attack poultry. 



The white-backed skunks (C onepatus) live in the South, mostly out 

 of the range of field mice. They destroy many other kinds of rats 

 and mice. 



The mink (Lutreola) feeds commonly upon fish and other aquatic 

 animals, but sometimes raids poultry kept near streams. It destroys 

 meadow mice as well as other small rodents. The fur is in such 

 demand, however, that minks are not likely to become sufficiently 



