its geographical sub-species, only two or three other species of
rock-pigeons are known; and these have not any of the characters of
the domestic breeds. Hence the supposed aboriginal stocks must either
still exist in the countries where they were originally domesticated,
and yet be unknown to ornithologists; and this, considering their
size, habits, and remarkable characters, seems very improbable; or
they must have become extinct in the wild state. But birds breeding on
precipices, and good fliers, are unlikely to be exterminated; and the
common rock-pigeon, which has the same habits with the domestic
breeds, has not been exterminated even on several of the smaller
British islets, or on the shores of the Mediterranean. Hence the
supposed extermination of so many species having similar habits with
the rock-pigeon seems to me a very rash assumption. Moreover, the
several above-named domesticated breeds have been transported to all
parts of the world, and, therefore, some of them must have been
carried back again into their native country; but not one has ever
become wild or feral, though the dovecot-pigeon, which is the
rock-pigeon in a very slightly altered state, has become feral in
several places. Again, all recent experience shows that it is most
difficult to get any wild animal to breed freely under domestication;
yet on the hypothesis of the multiple origin of our pigeons, it must
be assumed that at least seven or eight species were so thoroughly
domesticated in ancient times by half-civilized man, as to be quite
prolific under confinement.

An argument, as it seems to me, of great weight, and applicable in
several other cases, is, that the above-specified breeds, though
agreeing generally in constitution, habits, voice, colouring, and in
most parts of their structure, with the wild rock-pigeon, yet are
certainly highly abnormal in other parts of their structure: we may