COMMON CARRION HAWK 73 
mango. In the course of a single day I have examined 
five or six broods of young Chimangos, and by 
pressing a finger on their distended crops made them 
_disgorge their food, and found in every instance 
that they had been fed on nothing but the young of 
the Téru-réru. I was simply amazed at this whole- 
sale destruction of the young of a species so secret 
in its nesting-habits; for no eye, even of a Hawk, 
can pierce through the leafage of a cardoon bush, 
ending near the surface in an accumulated mass of 
the dead and decaying portions of the plant. The 
explanation of the Chimango’s success is to be found 
in the loquacious habit of the fledglings it preys on, 
a habit common in the young of Dendrocolaptine 
species. The intervals between the visits of the parent 
birds with food they spend in conversing together 
in their high-pitched tones. If a person approaches 
the solid fabric of the Oven-bird (Furnarius rufus) 
when there are young in it, he will hear shrill laughter- 
like notes and little choruses, like those uttered by 
the old birds, only feebler; but in the case of that 
species no harm can result from the loquacity of 
the young, since the castle they inhabit is impreg- 
nable. Hovering over the cardoons, the Chimango 
listens for the stridulous laughter of the fledglings, 
and when he hears it the thorny covering is quickly 
pierced and the dome broken into. 
Facts like these bring before us with startling 
vividness the struggle for existence, showing what 
great issues in the life of a species may depend on 
matters so trivial, seemingly, that to the uninformed 
