SELBORNE, _Feb. 19th_, 1770.
Dear Sir,--Your observation that "the cuckoo does not deposit its egg
indiscriminately in the nest of the first bird that comes in its way,
but probably looks out a nurse in some degree congenerous with whom to
intrust its young," is perfectly new to me, and struck me so forcibly
that I naturally fell into a train of thought that led me to consider
whether the fact was so, and what reason there was for it. When I came
to recollect and inquire, I could not find that any cuckoo had ever
been seen in these parts, except in the nest of the wagtail, the
hedge-sparrow, the titlark, the white-throat, and the redbreast, all
soft-billed insectivorous birds. The excellent Mr. Willughby mentions
the nest of the _Palumbus_ (ring-dove), and of the _Fringilla_
(chaffinch), birds that subsist on acorns and grains, and such hard
food: but then he does not mention them as of his own knowledge, but
says afterwards that he saw himself a wagtail feeding a cuckoo. It
appears hardly possible that a soft-billed bird should subsist on the
same food with the hard-billed: for the former have thin membranaceous
stomachs suited to their soft food, while the latter, the granivorous
tribe, have strong muscular gizzards, which, like mills, grind, by the
help of small gravels and pebbles, what is swallowed. This proceeding
of the cuckoo, of dropping its eggs as it were by chance, is such a
monstrous outrage on maternal affection, one of the first great
dictates of nature, and such a violence on instinct, that, had it only
been related of a bird in the Brazils, or Peru, it would never have
merited our belief. But yet, should it further appear that this simple
bird, when divested of that natural στοργὴ that seems to raise the kind
in general above themselves, and inspire them with extraordinary
degrees of cunning and address, may be still endued with a more
enlarged faculty of discerning what species are suitable and
congenerous nursing-mothers for its disregarded eggs and young, and may
deposit them only under their care, this would be adding wonder to
wonder, and instancing, in a fresh manner, that the methods of
Providence are not subjected to any mode or rule, but astonish us in
new lights, and in various and changeable appearances.
What was said by a very ancient and sublime writer concerning the defect
of natural affection in the ostrich may be well applied to the bird we
are talking of:
"She is hardened against her young ones, as though they were not hers:
"Because God hath deprived her of wisdom, neither hath He imparted to
her understanding."
_Query_.--Does each female cuckoo lay but one egg in a season, or does
she drop several in different nests according as opportunity offers?