METHODS OF BIRD STUDY 



43 



too small for flight. The last record of the dodo was in 1681. 

 Both of these remarkable species were unwittingly extermi- 

 nated by the introduction into the islands of hogs, which de- 

 stroyed their eggs and young. 



There are in North America ten genera and seventeen 

 species and varieties of pigeons and doves. Most of these are 

 Western and Southern. The two named below suggest most 

 important problems for eastern North America. For the Rocky 



FIG. 19. Egg of passenger pigeon, on black velvet, in nest of mourning dove 



The pigeon laid only one egg, about 1| inches long; the dove, two eggs about 

 1 inch long. This figure thus furnishes a decisive means of distinguishing the two 

 species. Photograph from specimens in the American Museum of Natural History 



Mountain and Pacific States the types studied should be the 

 band-tailed pigeon, Columba fascidta, from British Columbia 

 to Mexico; Viosca's pigeon, O.f. vidscce, southern Lower Cali- 

 fornia ; and the red-billed pigeon, C. flavirfotris. 



Passenger pigeon Ectopistes migratorius. This most valuable of 

 North American pigeons existed less than forty years ago in flocks 

 which stretched from horizon to horizon. It is now a serious question 

 whether the last living specimen has not been seen. 



