46 
Mr. P. L. Sclater on the 
the long grass or bushes, where they have lain during the 
day, to feed; and at that time they can be heard calling to 
each other in every direction. Their note is a loud and oft- 
repeated whistle uttered in a low key. 
Rhea darwini. 
Common on the higher tableland, but rarely seen in the 
immediate neighbourhood of the colony. The feathers of 
this bird form the chief article of barter which the Indians 
give in exchange for yerba, sugar, &c. During my visit we 
made two hunting-excursions in search of Rheas and Gua- 
nacos. The former sometimes lie very close, usually under 
the shelter of a bush, and will then allow you to pass within a 
few yards of them without moving. When flushed they en¬ 
deavour to run with the wind, partly opening their wings, 
which act as sails. It requires a good dog to overtake an 
old bird when he gets a start of a hundred yards. I was told 
that the colonists have found as many as thirty-two eggs in 
one nest, and when such a number is laid they consider them 
the produce of more than one female; they sometimes flush 
the male bird from the-nest. It is an event of common oc¬ 
currence to find single eggs about the campo smaller than 
those in nests; and these are supposed to have been dropped 
by immature birds which have not commenced to lay 
regularly. 
IV .—Note on the South-American Song-Sparrows. 
By P. L. Sclater. 
(Plate I.) 
It is a singular fact that, while Zonotrichia pileata is generally 
diffused over Central and South America, and is in many 
places a most abundant species, the only other two members of 
the same genus that occur within the neotropical region are 
confined to La Plata and Patagonia. So little known, more¬ 
over, are the latter, that, with a tolerably extensive acquaint¬ 
ance with South-American birds, I have never met with but 
