Cape San Antonio, Buenos Ayres. 155 
though eggs may be taken as late as November or December. 
It is then semigregarious in its habits, and, notwithstanding 
that an isolated nest is of common enough occurrence, several 
may be found close to each other in some favourite locality. 
Once I found ten nests in one swamp, some of which were 
within ten yards of each other. The deepest fens are those 
chosen; and the nest is placed among the thickest and 
highest rushes, rarely at the edge of clear water. It is a 
strong construction, capable of supporting a man’s weight, 
and is built of thick stems or sticks of a water-plant, stems 
of “hunco,” and of different kinds of water-grasses, rising 
from two to three feet above the surface of the water, with a 
diameter at the top of about two feet. There is sometimes 
a hollow for the eggs ; but the top is as often quite flat. The 
birds occasionally sit close ; and I have more than once found 
that it tried my horse’s nerves rather severely to come sud- 
denly on a nest off which rose one of these great ungainly 
creatures. It is rarely difficult to find the nest; for the bird 
usually stands up on it on hearing any one in the vicinity, 
and consequently its head and neck may be seen above the 
rushes a hundred yards off. 
Four is the largest number of eggs laid; but three is the 
general clutch; and the latter number are frequently hatched 
out. They are of a chalky, dirty-white colour, and average 
335 x 23%, with a considerable variation. 
40. PLEGADIS FALCINELLUS (L.). 
Of very irregular occurrence. In December of 1875 ! saw 
a flock of about a hundred ; and during the remainder of that 
month a few were to be seen about the plains. On the 5th 
of January of the ensuing year four flocks, of about ten each, 
were observed flying in a northerly direction; after which, 
at the end of March, I saw a pair in one of the swamps. 
Again in December of 1877 it was generally and abundantly 
distributed, disappearing about the beginning of January. 
My last note refers to a solitary bird seen in the middle of 
April of the same year. The foregoing records all the appear- 
ances of this bird during the last seven years. Such a flock 
M2 
