502 The Roller-like Birds 



Nesting Habits. The nesting habits of the Hornbills are without a parallel 

 in the bird world. This chapter in their life history was naturally received with 

 incredulity when first brought to scientific attention, but has since been abun- 

 dantly confirmed by competent observers. Selecting a cavity of suitable size 

 in the trunk or a large limb of a tree, the female enters, even before depositing 

 the clutch of eggs, when the male, assisted to some extent by the female, pro- 

 ceeds to wall up the entrance with mud, sometimes mixed with the bird's 

 own droppings or composed entirely of the latter substance, leaving only a 

 narrow slit through which the tip of the bill of the female may be thrust 

 to receive the food passed in by the male outside. Within these cramped 

 quarters the eggs are laid and incubated, and the young, born naked and 

 helpless, are cared for until they are nearly or quite fledged, before the 

 barrier is broken down and the mother and offspring liberated. The male 

 is said to be very assiduous in supplying the female with food, and after 

 all her incarceration may not be such a hardship as it would at first seem, 

 for if dragged forth both she and the young are found to be in excellent 

 flesh, a circumstance well known to the natives, who lose no opportunity 

 in securing the occupants of a nest whenever they can find one. The nest 

 cavity, as may be supposed, presents a very unsanitary appearance and 

 odor, and when the female is hauled out she likewise presents a bedraggled 

 and forlorn presence, being unable to fly or even stand up. But as if all this 

 was not a sufficiently severe ordeal, it appears that the female undergoes a com- 

 plete moult during the imprisonment. This fact, like so many others in the 

 economy of the Hornbills, was at first deemed impossible, but it is now settled 

 beyond question as true. Some years ago Dr. Giinther of the British Museum 

 exhibited before the Zoological Society of London the hollow trunk of a tree 

 from Graham Town, Cape Colony, in which a Hornbill (Lophoceros melan- 

 oleucus] had nested. He said: "The female when taken was unable to fly and 

 was simultaneously moulting all the wing- and tail-feathers, thus presenting 

 the appearance of a half-fledged young bird. This species, therefore, confirms 

 the observation made on other species of the genus, viz., that the Hornbills pass 

 through a complete moult in the six or eight weeks during which they are im- 

 prisoned with the eggs and young." The eggs are from two to three or four 

 in number and are white when laid, but they soon become soiled and discolored. 

 Another of the remarkable phenomena connected with the life history of the 

 Hornbills, brought to scientific attention by Bartlett, Flower, and Murie, and 

 since confirmed by others, is the so-called vomiting up of gizzard-sacs contain- 

 ing food. That is, at intervals during the nesting period, and perhaps at other 

 times, the males of certain species throw up a sac some three inches long and 

 two inches in diameter, in which is contained nuts, fruit, and berries, which it 

 is supposed is passed to the female during her incarceration, and which serve 

 to supply her with the necessary food. The structure of these sacs has been 

 investigated and demonstrated to be a sort of lining to the gizzard found inside 

 the regular lining of this organ and thrown up practically entire. The sac is 

 apparently formed by the rapid development of the cells just below the inner 



