334 



ELEMENTARY ZOOLOGY. 



It is one of the large sources of human food. Turkeys, 

 guinea-fowls, and peacocks contribute in less degree. The 

 numerous varieties of chicken are believed to have come, 

 by breeding and selection, from a wild species native to 

 southern Asia. The game birds of this order would 



FIG. 140. Ruffed grouse (Bonasa umbellus). Photo by Folsom. 



quickly become extinct in settled regions, but for the 

 laws protecting them at critical seasons. 



Closely related to the Gallinae are the doves and pigeons 

 (Columbse) . It is a small order of about a dozen species 

 which are native to America. None of these are now 

 very numerous. Formerly, the passenger pigeon occupied 

 the region east of the Mississippi River in great flocks 

 of millions of individuals, but is now extinct or on the 



