54 BULLETIN 135, UNITED STATES NATIONAL MUSEUM 



evidently fades with incubation, as the heavily incubated eggs are a much 

 lighter blue than the freshly laid ones. This is probably the largest breeding 

 colony of these birds in southern California west of the mountains, 



A. O. Treganza writes to me that this ibis is not an uncom- 

 mon breeder in suitable localities in Utah. There is a colony of 

 about 100 pairs on the black sloughs about 8 miles from Salt Lake 

 City, a colony at the mouth of the Jordan River of about 100 pairs 

 and he knows of four colonies, two of about 75 to 100 pairs and two 

 of about 150 to 200 pairs at the mouth of Bear River. They breed 

 in company witli snowy egrets and black-crowned night herons and 

 in three cases with Treganza herons, nesting in tules growing in 

 water about waist deep. In some instances the nests are made on 

 the dead tules of the year previous, which have been broken and 

 matted down by the winter snows, while in other cases they consist 

 of entirely new nests attached to and on the new growing tules and 

 reeds. 



Eggs. — This ibis usually lays three or four eggs, but five, six or 

 even seven have been found in a nest. They are ovate, elliptical 

 vateor elongate ovate in shape. The shell is smooth or very finely 

 pitted, with little or no gloss. The color varies from " Niagara 

 green" to "pale Nile blue." The measurements of 46 eggs average 

 51.5 by 36 millimeters; the eggs showing the four extremes measure 



55 by 37, 52 by 38, 46 by 35.5 and 50.5 by 33 millimeters. 



Young. — Incubation is said to last for 21 or 22 days and probably 

 both sexes incubate, as is known to be the case with the glossy ibis. At 

 the time we visited the rookery in Texas, referred to above, we found 

 young of all ages from newly hatched to those which were able to 

 fly. The youngest birds showed signs of fear, but remained in 

 the nest or made only feeble attempts to leave it But the older 

 birds, one-third grown or more, were very timid and very precocial; 

 they left the nests as we approached and scrambled off through the 

 tules with great agility and skill; the larger ones tried to fly and, if 

 they fell into the water, they flopped over the surface or swam 

 away. 



Plumages.— The downy young of the white-faced glossy ibis is not 

 a beautiful creature. It is scantily covered with dull black down, 

 through which the pin-feathers soon begin to show; there is a white 

 patch on the back of the crown; the bill is pale flesh-color, black at 

 the tip and at the base, with a black band in the middle. This 

 parti-colored bill is also characteristic of the juvenal plumage and 

 does not disappear until September. In the juvenal plumage the 

 rich chestnut hues are wholly lacking; the head, neck, and under 

 parts are dull grayish brown; but the plumage of the upper parts, 

 back, wings, and tail, is a rich, glossy, metallic green. A partial molt 

 in September produces a head and neck plumage much like that of 



