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
look in vain throughout the whole great family of Columbid for a beak
like that of the English carrier, or that of the short-faced tumbler,
or barb; for reversed feathers like those of the jacobin; for a crop
like that of the pouter; for tail-feathers like those of the fantail.
Hence it must be assumed not only that half-civilized man succeeded in
thoroughly domesticating several species, but that he intentionally or
by chance picked out extraordinarily abnormal species; and further,
that these very species have since all become extinct or unknown. So
many strange contingencies seem to me improbable in the highest degree.
Some facts in regard to the colouring of pigeons well deserve
consideration. The rock-pigeon is of a slaty-blue, and has a white rump
(the Indian sub-species, C. intermedia of Strickland, having it
bluish); the tail has a terminal dark bar, with the bases of the outer
feathers externally edged with white; the wings have two black bars;
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