191. Plegadis guarauna, (Gm.)
Kesident, but much more common in summer than in winter. On the 16th of May, 1877, Mr. G. B. Sennett and I visited a large patch of tul6- reeds growing in a shallow lagoon, about ten miles from the fort, in which large numbers of this Ibis and several kinds of Herons were breeding. The reeds covered an area of perhaps seventy-five acres or less, growing in water three or four feet in depth. Irregular channels of open water traversed the reeds here and there, but the bottom was comparatively firm, and there was little difficulty in wading in any direction. Besides the Ibises, the Great and Little White Egrets, Lou- isiana and Night Herons, and several other birds were breeding here. Often nests of all these species were placed within a few feet of each other, but there was a tendency towards the different kinds forming little nesting groups of ten or fifteen pairs. The reeds grew about six feet above the surface of the water, and were either beaten down to form a support for the nests, or dead and partly floating stalks of the previous year were used for that purpose.
It was impossible to estimate the number of the Ibises and different Herons nesting here. On approaching the spot, many would be seen about the edges of the lagoon or flying to or from more distant feeding grounds, but upon firing a gun a perfect mass of birds arose, with a noise like thunder, from the entire bed of reeds, soon to settle down again. Both nests and eggs of the Ibises were quite unlike those of any of the Herons, and could be distinguished at a glance. The nests were made of broken bits of dead tul6s, supported by and attached to broken and upright stalks of living ones. They were rather well and compactly built, and were usually well cupped, quite unlike the clumsy platforms of the Herons. The eggs were nearly always three in number, and at this date were far advanced in incubation ; many nests contained young of all sizes. Fifty eggs now before me average 1.95 by 1.35, the extremes being 2.20 by 1.49 and 1.73 by 1.29; they are decidedly pointed at the smaller end, and are of a deep bluish-green color.
On May 7 of the following year, I revisited this heronry, but there were no nests, and very few Ibises or Herons were to be seen. I am inclined to think that they moved to some other part of the extensive prairie, in several parts of which were beds of reeds similar to the one above described, but I was prevented by sickness from making any further investigations.
The young, when first hatched, are clothed in blackish down; the bill i^whitish, with dusky base. When nearly fledged, the wings and back hav$ a very marked metallic lustre ; the base of bill, with terminal one- fourth inch and a two-fifths inch median band, black ; the intervening portions pinkish-white. — (Ibis ordi, Dresser, Ibis, 1866, 32. — Falcinel- lus g., Sennett, B. Eio Grande, 56.)
