62 BIRDS OF LA PLATA 
with pale fuscous, and is less in size than her mate. 
They remain with us all the year and live in pairs, 
the sexes in this species being faithful. Sometimes 
they are seen associating in small flocks, but I am 
inclined to believe that only the young unmated 
birds are gregarious. In 1867-8, during the cholera 
epidemic in Buenos Ayres, the Sparrows all dis- 
appeared from the town, and I was told by the 
manager of a large steam flour-mill in the town that 
the birds had not gone away, but had died. They 
were found dead all about the mill, where they had 
been very abundant. My informant was a careful 
observer, and I have no doubt that he was correct 
in what he told me. 
In spring and summer the male sings frequently 
with great energy, but without much melody. After 
a hurried prelude of sharp chirps and trills, he pours 
out a continuous stream of sound, composed of 
innumerable brief notes, high and shrill as those of 
a bat, wounding the ear with their excessive sharp- 
ness, and emitted so rapidly that the whole song is 
more like that of a cicada than of a bird. This piercing 
torrent of sound is broken at intervals by a long, 
grave note, or half a dozen short, rapid notes in a 
lower key, which come as an agreeable relief. 
In towns they build in walls, like the English 
Sparrow; in country places they always select the 
domed nest of some Dendrocolaptine species to 
breed in. Possibly in some districts where I have 
not been, this Sparrow selects other breeding-sites ; 
my experience is that outside of a town it never lays 
