Volume 1. Number 12. 



NOTES ON THE ONTOGENY OF THE 



WHITE IBIS, GUARA ALBA 



By C. William Beebe, Curator of Birds. 



Part I — Breeding Habits. 



As soon as the White Ibises are placed outdoors in the large 

 flying cage, in the spring of the year, the breeding pairs spend 

 much of their time in the small tree in which they have nested 

 for the past two seasons. Usually one of the two nests has sur- 

 vived the winter's storms and shows at least a solid basal plat- 

 form of twigs. There seems to be little definite courtship in 

 these captive birds, and I am quite certain that they remain 

 paired throughout the year. There is much quarreling over the 

 nests, but as for two seasons in succession the same sites have 

 been chosen, there is little doubt that each pair occupies the 

 same nest or nesting site. 



At first the males remain in the vicinity of the tree more 

 than the females, and indeed, for many days before actual build- 

 ing commences the males will spend almost the entire day, stand- 

 ing on the old nest or a nearby branch, one leg drawn up, but 

 watchful and ready with raised wings, open beak and inflated 

 chin pouch to frighten away any other birds intruding on their 

 territory. 



The sexes share equally in bringing material for the nest, 

 although the actual interlacing of twigs seems to be the duty of 

 the female. At least I have seldom seen the male do more than 

 awkwardly fiddle about with a twig which he had brought, while 

 upon the arrival of his mate he stepped out upon a branch and 

 allowed her to attend to the actual building. 



I have never known when the first egg was deposited and 

 not until the full set is laid is there any abstract hint of eggs in 

 the nest, and this only from the continual setting of the birds. 

 Both take part in incubation, and during different times in the 

 day I have seen the male as often as the female on the eggs. It 

 is not uncommon for the male to bring fish to his mate, but I 



