FAMILY Cuculidz. 
obscure interval of a third or fourth (as in above record} 
Again, these tones are at times so distinctly separated 
that they assume an individual independence, with the 
intervals no longer obscure: 
This is by no means the common song of the Black- 
bill, but it certainly isnot rare. Here is variety again: 
4=92 
A 
Cucucoo-90, CUucucod-0g CK-€00-0Q CUuCuCOO-00. 
the little musician is not content until he shall ring 
all the possible changes of such vocal limitations! Mg. 
Cheney is also an authority for the statement that this 
bird is quite capable of singing his song in two well- 
separated tones. He writes: ‘‘ Early one June morn- 
ing, . . . abird was exercising his voice in a manner 
that set me on the alert; it was the voice of a Cuckoo, 
but not the Cuckoo’s song. 
A) S:P-Cheney's record, 
The instant I heard ‘Cuckoo’ . . . giving the in- 
terval of a fourth, I experienced a thrill of satisfaction 
such as no similar discovery had afforded. Other ears, 
sharper than mine, had heard all, unknown to me; 
and there was great rejoicing,—the Cuckoo was learning 
to sing!” But I have long been of the opinion myself 
that the Cuckoos, all of them, were birds whose voices 
were set in two distinct tones ; in the case of the Ameri- 
can species it has simply been a question of its ability 
to separate or individualize those tones. The European 
18 
