284 



ZOOLOGY 



the new enemies are gained or their bid ones overtake 

 them, and then the numbers of the exotic form become 

 reduced ; a new equilibrium becomes established. 



The English sparrow belongs to the family Fringillidae, 

 which includes sparrows and finches. This is a large 



FIG. 1?(J4. The American crossbill (Loxia curvirostra) . 



family, comprising over live hundred species, found in all 

 parts of the world, excepting, originally, Australia. In 

 the United States this is the largest family of birds, com- 

 prising in most places about one-seventh of the species. 

 Among common or striking native Fringillidse may be 



