Pigeons and Poultry. 69 



themselves. To this family belong the hawks, kites, 

 buzzards and harriers, as well as the larger eagles, 

 ospreys, and falcons. 



CHAPTER XIII. 



CLASSIFICATION OF BIRDS CONTINUED. 



40. Order 7, Pigeons (Gyrantes). This well- 

 marked group consists of the doves and pigeons, 

 characterised by having a gristly plate covering the 

 base of the upper mandible, pierced in front by the 

 nostrils. They are vegetable-feeders, with a large 

 glandular crop which sometimes secretes a milky fluid 

 with which the parents nourish the young birds. 

 They have a strong gizzard, shielded or feathered 

 tarsi, and four usually free toes all on the same level, 

 with short, slightly-hooked claws. They are mostly 

 birds of powerful flight, and have ten primary quill 

 feathers in their long pointed wings, and twelve or 

 rarely sixteen rectrices. They are mostly social birds, 

 often living in great societies. The pigeons, wood- 

 quests, and doves are familiar instances, as also are 

 the passenger pigeons of North America, which mi- 

 grate in millions, darkening the air by their flocks. 

 Our common pigeons, in all their varieties, are de- 

 scended from the rock-dove, Columba livia. The 

 curious dodo of Mauritius was an aberrant large 

 pigeon incapable of flight, and hence it was easily 



