58 A NATURAL HISTORY OF THE CUCKOO. 
asserts of a species of Erythrophrys common on that continent, and 
commonly termed the Carolina Cuckoo, that “ they are accused, and 
with some justice, of sucking the eggs of other birds; like the 
Crow, the Blue Jay, and other pillagers:” and this statement is 
amply confirmed by Mr. Nuttall, whose personal testimony may be 
considered decisive. Now the birds ailuded to, though differing in 
several points, and particularly in that of incubating and tending 
their broods, are nevertheless closely related to the Cuckoo; inso- 
much that what constitutes the food of one may be predicted, with 
little hazard, as that of the other also. An ovivorous propensity is 
furthermore common to several of the yoke-footed tribes. The 
Toucans have been long notorious for it ; and Audubon has remark- 
ed it even in a species of Woodpecker, which he describes to enter 
pigeon-houses for the purpose of feeding on the eggs. 
It may be well to notice here an erroneous statement which has 
crept into many works of natural history, to the effect that the lax 
and flaccid stomach, both of the Cuckoo and of its American rela- 
tives just mentioned, is internally lined “with a growth of fine 
down or hair, of a light fawn colour. It is difficult,” remarks Wil- 
son, “ to ascertain the particular purpose which nature intends by 
this excrescence ; perhaps it may serve to shield the tender parts 
from the irritating effects produced by the hairs of certain caterpil- 
lars, some of which are said to be almost equal to the sting of a 
nettle.” But the truth is, that the appearance in question is no- 
thing more than the hair-like spines of the caterpillars on which 
the bird had been feeding, as becomes at once apparent on viewing 
it with the assistance of a lens; and as they accumulate these spines 
are worked into a hard oval ball by the mechanical action of the 
stomach, which is finally, as already mentioned, ejected by the 
mouth—a circumstance of ordinary occurrence throughout the series 
of animal-feeding land birds. 
We arrive now at the most extraordinary portion of the Cuckoo's 
history, its parasitic habit of laying in other bird’s nests, and leaving 
its progeny to the fostering care of strangers. Hence it is observa- 
ble of them that they never pair, nor are they polygamous, like do- 
mestic poultry, but associate promiscuously. 
The reason that the Cuckoo thus deviates from the general prac- 
tice of the feathered race—that is to say, the ultimate or remote 
cause of it—is obscure; but the proximate or immediate cause may, 
I suspect, be found in a structural peculiarity, which, 1 am inclined 
to think, retards the developement of the eggs, so that alonger time 
than usual is required to intervene between their successive deposi- 
