16 Mr. E. Gibson on the Ornithology of 
Forty-seven specimens average #3 x 73, with some con- 
siderable variation. They are round in shape, and strong- 
shelled, the colour a glossy white or bluish white. 
21. Furnarius rurus. (Red Oven-bird.) Native name 
SAOrnerold, 
That this species is abundant I need not say ; and it is also 
probably one of the best-known of our Buenos-Ayrean birds. 
It is confined almost entirely to the woods ; for the open plains 
are unsuited to its building-habits. But any rancho, how- 
ever solitary, can boast of a pair, as it only wants something 
to perch its nest upon. 
Its appearance is uninteresting, though its gait (which is 
like that of a gigantic Robin) is rather amusing. The only 
note or cry it possesses is also rather peculiar, being a suc- 
cession of loud (but not unmelodious) short notes, accom- 
panied by a corresponding agitation of the wings, similar to, 
but more rapid than, that of the Cock when it crows. The 
wings, however, do not strike the body. It is by no means 
chary of its voice either, and may be heard constantly, not 
only through the woods, but about the houses ; for it is nearly 
as fearless as the Sparrow. 
The flight, again, resembles that of a Thrush, though per- 
haps it is neither so rapid nor so strong. 
Breeding-Notes.—Well might Mr. Durnford remark that 
“its breeding-habits are rather irregular ;” for it begins to 
build in the autumn, and sometimes takes all the winter to 
finish its nest. The work is mostly done in the morning ; and 
how carefully the mud is mixed and tempered (in little balls) 
may be inferred from the strength of the nest. When once 
dry it will easily support a man’s weight; and my usual 
method of getting at the eggs is by cutting a hole in the side 
with a strong knife. The naturalist cannot but wonder at 
the extraordinary imstinct which teaches the bird how to 
break the regular round of the foundation in order to form 
the entrance, to make that entrance of such a nature as to be 
easily defended by the parent bird against small quadrupeds 
while it is inaccessible to an opossum or a human hand, and 
