136 THE WORLD'S BIRDS. 



They are fed by the parents, inserting their soft 

 swollen bills into the mouths of these. The first 

 food is a milky secretion from the old birds' crops, 

 which is later exchanged for the ordinary food of 

 the parents softened. 



Nest. — Very primitive in structure, an open platform 

 of twigs or grass -stems ; usually placed in a tree 

 or bush, sometimes on the ground or in holes of 

 trees, rocks, or buildings. 



Eggs. — One or two ; glossy and unspotted, white, rarely 

 slightly tinted. 



Incubation. — From two to four weeks. 



Courtship. — Very demonstrative, but differing much 

 in different groups ; the throat is usually distended, 

 and the tail often spread, but not the wings. 

 Sailing nuptial flights are indulged in by many 

 species, especially the Turtle-doves. 



Food. — Mainly vegetable, leaves, buds, grain and 

 fruit ; but worms and small snails, etc., are also 

 eaten. They drink by a continued draught, not 

 in sips. 



Gait. — A walk, graceful enough in the ground-feeders, 

 but an awkward waddle in those which keep mostly 

 to trees. Some of these tree -pigeons hop occasion- 

 ally, and some ground species run quickly. 



Flight. — Swift and decided, usually by continued 

 rapid strokes of the half-expanded wings. Some 

 species sail at times, but none seem to soar for 

 any distance, or to fly with slow strokes. The neck 

 and legs are outstretched in flight. 



Note. — Usually pleasant, a " coo " or purr ; a whistle 

 in some fruit -pigeons, and a boom, almost a roar^ 

 in others. There is a short, dull alarm-note, but 

 except for the love -note they are silent birds. 



Disposition and Habits. — Pigeons are rather stupid 

 on the whole ; wary when molested, and quarrel- 

 some in a weak sort of way. In fighting, they 



