ANIMALS THAT BECOME PESTS 269 



forced to subsist chiefly on the bark of bushes and the ber- 

 ries of the wild rose. Whenever they gnaw the bark from 

 young fruit-trees, it is a sign that they are hard pressed for 

 food. 



Rabbits breed very rapidly, often raising three litters a 

 year, and if not kept in check by birds of prey and carniv- 

 orous animals, would soon become altogether too numerous. 

 In Australia and New Zealand, the rabbits "introduced"^ 

 from Europe have multiplied until they have become a fear- 

 ful scourge, and are now so numerous it is impossible even 

 to keep them in check. Possibly the use of their flesh as 

 food, and their skins as "fur," may lead to an abatement of 

 the evil. The moral of the rabbit in Australia, the mon- 

 goose in the West Indies, and the English sparrow in Amer- 

 ica, is — before "introducing" a foreign species of bird or 

 mammal into America, take expert advice, — and then don't 

 do it! This refers to species able to live wholly by their 

 own efforts when imported and set free. 



Bibliographical 



The following popular papers are of special interest and 

 value : 



On Jack " Rabbits."— The Jack Rabbits of the United States. By Dr. T. S. 



Palmer; pamphlet, 88 pages. Bulletin No. 8, Biological Survey, 



Department of Agriculture. Washington, 1897. 

 On Gopher s.-^The Pocket Gophers of the United States. By Vernon 



Bailey, pamphlet, 47 pages. Bulletin No. 5, as above, 1895. 



1 A species transplanted from one country to another is said to be "introduced." 



