ring to the character of the
wild rock-pigeon, and to vary in a similar manner. To these arguments may
be added the extreme improbability that a number of species formerly
existed, which differed greatly from each other in some few points, but
which resembled each other as closely as do the domestic races in other
points of structure, in voice, and in all their habits of life. When these
several facts and arguments are fairly taken into consideration, it would
require an overwhelming amount of evidence to make us admit that the chief
domestic races are descended from several aboriginal stocks; and of such
evidence there is absolutely none.

The belief that the chief domestic races are descended from several wild
stocks no doubt has arisen from the apparent improbability of such great
modifications of structure having been effected since man first
domesticated the rock-pigeon. Nor am I surprised at any degree of
hesitation in admitting their common {204} origin: formerly, when I went
into my aviaries and watched such birds as pouters, carriers, barbs,
fantails, and short-faced tumblers, &c., I could not persuade myself that
they had all descended from the same wild stock, and that man had
consequently in one sense created these remarkable modifications. Therefore
I have argued the question of their origin at great, and, as some will
think, superfluous length.

Finally, in favour of the belief that all the races are descended from a
single stock, we have in _Columba livia_ a still existing and widely
distributed species, which can be and has been domesticated in various
countries. This species agrees in most points of structure and in all its
habits of life, as well as occasionally in every detail of plumage, with
the several domestic races. It breeds freely with them, and produces
fertile offspring. It varies in a state of nature,[345] and still more so
when semi-domesticated, as shown by comparing the Sierra Leone pigeons with
those of India, or with those which apparently have run wild in Madeira. It
has undergone a still greater amount of variation in the case of the
numerous toy-pigeons, which no one supposes to be descended from distinct
species; yet some of these toy-pigeons have transmitted their character
truly for centuries. Why, then, should we hesitate to believe in that
greater amount of variation which is necessary for the production of the
eleven chief races? It should be borne in mind that in two of the mo