128 THE STORY OF BIRD-LIFE. 



ture, composed simply of the feathers of the 

 female. The hollow of the tree communicates 

 with the exterior air by means of a long aperture, 

 which, just before the period of incubation, is 

 closed up almost entirely by the male, simply 

 leaving a long slit open, up and down which 

 the beak of the enclosed female can move. The 

 substance used in thus closing the aperture 

 closely resembles some vegetable resin, and is 

 probably composed of a gastric secretion com- 

 bined with the woody fragments of fruit. It 

 should be noted that this slit is always in close 

 proximity to the nest, so that the female can 

 easily protude her beak for food without moving 

 from her sitting-position. During incubation the 

 male bird supplies the female with food in the 

 form of pellets of fruit, seeds, insects, portions 

 of reptiles, etc., the pellets being enclosed each 

 in a skin of rubber-like consistency. While 

 feeding the female, the male clings to the bark 

 of the tree, or sits on a branch if conveniently 

 near, and jerks these pellets into the gaping 

 beak of the hen, two to four pellets forming 

 a meal. During mastication (for it is a mistake 

 to suppose that the hornbills always bolt their 

 food entire) some fragments of the pellet fall 

 to the ground ; any seeds which these fragments 

 may contain take root, germinate, and sprout, 

 and the natives can judge approximately of the 

 date of incubation by the age of the seedlings. 

 When these are four-leaved, the eggs have been 

 hatched out for two or three weeks. At this 

 stage, though not always so early, the mother- 

 bird leaves the nest, breaking down the gluey 



