Cape San Antonio, Buenos Ayres. 157 
There were from three hundred to four hundred nests, as 
well as I could judge: of these three fourthswere of A. egretta ; 
and the remainder, with the exception of two or three dozen 
of N. obscurus, belonged te A. candidissima. 
Those of the first-mentioned species were slight platforms 
of hunco-stems, placed on the top of the broken huncos, at a 
height of from two to three feet above the water, and barely 
a yard apart. 
The nests of A. candidissima were built up from the water 
to the height of a foot or a foot and a half, with a hollow on 
the top for the eggs ; they were very compactly put together, 
of small dry twigs of a water-plant. A good many were dis- 
tributed among those of A. egretta; but the majority were 
close together, at one side of the colony, where the huncos 
were taller and less broken. 
The nests of Nycticorax obscurus much resembled the latter 
im construction and material; but very few were interspersed 
among those of the two other species, being retired to the side 
opposite A. candidissima, on the borders of some channels of 
clear water; there they were placed among the high huncos, and 
a few yards apart from each other. I also saw three or four 
close to the colony of Rostrhamus sociabilis (mentioned at the 
beginning of this paper), about a hundred yards away. 
The larger Egrets remained standing on their nests till I 
was within twenty yards of them, and lighted again whenIhad 
passed. In this position they looked much larger than when 
flying. The smaller Egrets first flew up onto the huncos above 
the nest, and then immediately took to flight, not returning, 
while N. obscurus rose and sailed away, uttering a deep 
squawk, squawk, long before one came near the nest. 
At one side of the colony a nest of Ciconia maguari, with 
two full-grown young, seemed like the reigning house of the 
place. 
It certainly was one of the finest ornithological sights I 
ever saw :—all around a wilderness of dark green rushes, 
rising above my head as I sat on horseback ; the clouds of 
graceful snowy-white birds perched everywhere, or reflected 
in the water as they flew to and fro overhead ; and the hundreds 
