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 Teru-reru. 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 



