262 AVES. 



The stiff, beautifully coloured plumage lies smoothly on the body, 

 and presents hardly any difference in the two sexes. The short legs 

 are unfitted for rapid and constant locomotion. The feet are cloven 

 (p. fissi) or ambulatory (p. ambulatorii), and the well-developed hind 

 toe rests on the ground. The Columbince have a paired crop, which 

 at the breeding season in both sexes secretes a creamy fluid for the 

 nourishment of the young. They are distributed over all parts of 

 the world. They live in pairs or in flocks in forests, and feed almost 

 exclusively on grain and seeds. The species which live in the north 

 are migratory (Zugvogel) ; others make short migration (Strichvogel), 

 while others are resident birds. They live in a state of monogamy, 

 and lay two, rarely three, eggs in a rudely-constructed nest. Both 



FIG. 6c2. Columba livia (after Naumann). 



sexes take part in hatching and bringing up the young. The young 

 leave the egg almost entirely naked, with closed eyelids, and, as 

 altrices, require the care of the mother for a considerable time. 



Fam. Colnmbidae. The beak, with smooth edges, never dentated. Columba 

 livia L., Rock-Dove (fig. 662). Slate-blue, with white wing-coverts and 

 two black bands on the wings and tail. It is the ancestral form of the 

 numerous races of domestic pigeon. It nests on rocks and ruins, and is dis- 

 tributed from the coasts of the Mediterranean over a great part of Europe and 

 Asia. C. (Paluinibcenas) cenas L., Stock-Dove ; Palumbus torquatus, Leach, 

 Ring-dove Ectopistcs migratorius L., Passenger Pigeon, North America ; 

 Turfvr auntus Bp., Turtle-Dove ; T. risorius Sws. ; Goura eoronata, Flem., 

 New Guinea. 



Fam. Didunculidee. Beak compressed, lower jaw dentated, with hooked 

 extremity. Didunc'ul'us strigirostris Gould, Samoa Islands 



