28 BULLETIN 135, UNITED STATES NATIONAL MUSEUM 



elongate ovate. The shell is smooth or finely granulated and with- 

 out any gloss. The ground color is usually bluish or greenish white, 

 varying in the brightest specimens from "pale olivine" to "pale 

 glaucous-green"; in some eggs the ground color is pale buff, from 

 ''cream buff" to "pale olive buff'." The eggs are usually hand- 

 somely marked with wide variation in patterns. They are irregularly 

 spotted and blotched with various shades of brown; the commonest 

 shades on the handsomest eggs are "bay, " "chestnut," and "au- 

 burn"; the darkest markings vary from "light seal brown" to "cin- 

 namon brown," and the lighter markings from "buckthorn brown" 

 to "clay color." Sometimes the eggs are uniformly spotted all over 

 the entire surface, with or without large blotches; sometimes the 

 spots or blotches are concentrated at the larger end; and sometimes 

 the eggs are very sparingly marked or even nearly immaculate. The 

 measurements of 80 eggs average 57.6 by 38.3 millimeters; the eggs 

 showing the four extremes measure 66.2 by 39.2, 53 by 42.3, 62 by 38 

 and 54.5 by 34 millimeters. 



Young. — The period of incubation is said to be 21 days. Audubon 

 (1840) says: 



The young birds, which are at first covered with a thick down of a dark gray 

 color, are fed by regurgitation. They take about five weeks to be able to fly, 

 although they leave the nest at the end of three weeks, and stand on the branches, 

 or on the ground, waiting the arrival of their parents with food, which consists 

 principally of small fiddler crabs and crayfish. On some occasions, I have found 

 them at this age miles away from the breeding places, and in this state they are 

 easily caught. As soon as the young are able to provide for themselves, the old 

 birds leave them, and the different individuals are then seen searching for food 

 apart. 



The breeding rookery I visited in Victoria County, Texas, on May 

 30, 1923, referred to above, gave me my best impression of the behavior 

 of young white ibises, for we reached it at the time of tlieir greatest 

 activity. Having previously located the probable site of the rookery 

 from a distance we found it quite a long trip ii\to it, through a series 

 of meadows, swamps, thickets, and groves of heavy forest growth. 

 Wlien we reached the thickest and wettest pji/t of the big swamp 

 where the willows, cypress, water oaks, and bu/ton bushes grew, and 

 where the drier spots supported a heavy groA^th of live oaks, elms, 

 tupelos, sweet gums, and black gums, festooned with long beards of 

 Spanish moss, we began to see the birds flying from their nests. 

 Way up in the tallest trees were the nests of tJie Ward herons and 

 lower down those of the Mexican cormorants atid water turkeys and 

 in a clump of willows on the edge of an open jspace was a colony of 

 American egrets. The air was full of white ibises, flying about in 

 all directions, and often with them came a Hash of pink and carmine, 

 as a band of roseate spoonbills flew out into the open, circled and 

 returned to alight on the bare tops of some tall dead trees, favorite 



