30 BULLETIN 135, UNITED STATES NATIONAL MUSEUM 



ence of it, in the mantle and body plumage and the head and neck is 

 always mottled with dusky and white. 



At the first complete postnuptial molt, during the following sum- 

 mer, the young bird assumes a plumage which is nearly adult, 

 including the white primaries with the bluish black tips; but some 

 signs of immaturity remain all through the second winter and spring. 

 Young birds breed in the second nuptial plumage, in which the head 

 and neck is still more or less mottled with dusky and a few brown 

 feathers are retained in the body plumage. At the second postnup- 

 tial molt, when over 2 years old, the young bird assumes the fully 

 adult dress. 



Adult apparently have a complete postnuptial molt and an incom- 

 plete prenuptial molt. The winter plumage of the adult, worn in 

 the fall and early winter, differs from the nuptial only in having 

 more or less dusky mottling in the crown and hind neck; the bill, 

 face, and legs at this season are dull flesh color. The mottling on 

 the head and neck disappears at the prenuptial molt and the naked 

 parts become brilliant red, bright vermilion, or Turkey red; the 

 gular pouch is distended in the nuptial display. 



Food. — A large breeding colony of ibises must soon exhaust the 

 food supply in the immediate vicinity of its rookery, although the 

 proximity of a good food supply largely governs the selection of a 

 nesting site. For this reason ibises often have to travel long distances 

 to and from their feeding grounds. These flights occur mainly in 

 the early morning and in the evening in the inland localities and at 

 the proper stages of the tides on the seacoast. Their favorite feeding 

 grounds are in the muddy, shallow waters of small lakes, ponds, and 

 bayous, or on the fresh or salt water marshes or meadows, where 

 crawfish and fiddler crabs abound. 



Audubon (1840) describes the feeding habits, as foUows: 



The manner in which this bird searches for its food is very curious. The 

 woodcock and the snipe, it is true, are probers as well as it, but their task requires 

 ess ingenuity than is exercised by the white or the red ibis. It is also true that the 

 white ibis frequently seizes on small crabs, slugs, and snails, and even at times 

 on flying insects; but its usual mode of procuring food is a strong proof that 

 cunning enters as a principal ingredient in its instinct. The crawfish often bur- 

 rows to the depth of 3 or 4 feet in dry weather, for before it can be comfortable 

 it must reach the water. This is generally the case during the prolonged heats 

 of summer, at which time the white ibis is most pushed for food. The bird, to 

 procure the crawfish, walks with remarkable care towards the mounds of mud 

 which the latter throws up while forming its hole, and breaks up the upper part 

 of the fabric, dropping the fragments into the deep cavity that has been made 

 by the animal. Then the ibis retires a single step, and patiently waits the result. 

 The crawfish, incommoded by the load of earth, instantly sets to work anew, and 

 at last reaches the entrance of its burrow; but the moment it comes in sight, the 

 ibis seizes it with his bill. 



Oscar E. Baynard (1913) has shown that the feeding habits of 

 ibises are much more beneficial than is generally supposed; he writes: 



