Neighbourhood of Buenos Ayres. 161 
Inside there are two rooms as it were, a passage leading from 
one to the other ; in the lower the eggs are laid, the upper 
one, it is supposed, being used as a roosting-place all the year 
round. Placellodomus front alls is not at all rare, frequenting 
damp places; I have found and identified three nests, all of 
which were placed at the ends of boughs about eight feet from 
the ground, being always of an oblong shape, never so round 
as that of the next species. The nest consists of sticks and 
twigs, lined with hair, and sometimes wool; the full com¬ 
plement of eggs is four. This species has very skulking habits. 
Placellodomus ruber is also common in marshy ground; 
its nest is similar to that of the last-mentioned species, and 
constructed of the same materials, but is rounder in shape. 
The bird is not easy to identify, as when disturbed it hides 
itself amongst thick reeds or bushes. The eggs are white, 
the full complement being four or five. They are similar to 
those of P. frontalis, but rather larger. 
STRIGIDiE. 
The Short-eared Owl (Otus brachyotus) is common in open 
lands, but is not often seen here; it flies towards dark, and 
feeds on beetles. The Burrowing-Owl (. Pholeoptynx cunicu- 
laria) is abundant, building in holes in the ground ; it is an 
Owl of diurnal habits, being fond of sitting on a thistle or 
clod of earth, whence it flies to seize insects on the wing. 
Its flight is undulatory, and performed by rapid strokes of the 
wings. From May to September this bird was common near 
here; after that they appear to have betaken themselves to 
the campo to build in the Biscacha- and Armadillo-holes, 
which there abound. 
FaLCONIDAE. 
Two or three pairs of Buteo pterocles frequent a wood near 
Chirilcay, about 100 miles from Buenos Ayres ; the male is 
slightly smaller than the female. The Chimango 39 (. Milvago 
chimango ) is very common, frequenting the open eampos in 
preference to the enclosed country. Polyborus tharus (the 
“ Carrancha ”) is common, especially in marshy places ; it 
feeds indiscriminately on dead fish, lizards, carcasses of 
