136 BIRDS OF LA PLATA 
The songsters, all included in the sub-order Oscines, 
rank higher in the scale as having a developed vocal 
organ, and the Old World Flycatchers rank with 
Thrushes and Nightingales in this division. The 
fact remains, however, that many ‘species in this 
highest sub-order are songless or are mere croakers 
or chatterers, whereas some of the Tyrant Birds 
have set songs and are sweet singers. The Tyrants 
in South America number over 360 known species— 
probably 400 would be nearer the right number now. 
There is a great variety in the size, form, and habits 
of different genera. There are among them birds 
with strong legs which seek their food on the ground, 
like Thrushes and Chats, which they resemble ; 
and there are others, also ground feeders, that perch 
on bushes and trees and watch the ground below 
until they spy an insect, then drop upon and capture 
it and return to the same perch. Others watch for 
flying insects and capture them in the manner of 
our European Flycatchers, and many others have 
the food-seeking habits of our Leaf-Warblers. 
Of the sixty or seventy species found in the Argen- 
tine country, I am acquainted with twenty-seven, 
and the largest of them is the Chocolate Tyrant first 
described. 
There is a striking resemblance to a Thrush in 
this species, when one sees it running on the ground 
with its beak somewhat elevated ; but when it stands 
or perches, opening and closing its broad tail with a 
graceful fan-like motion, the resemblance to the stiff 
automatic Turdus grows less, and when it flies 
