From these several reasons, namely, the improbability of man having formerly made seven or eight supposed species of pigeons to breed freely under domestication⁠—these supposed species being quite unknown in a wild state, and their not having become anywhere feral⁠—these species presenting certain very abnormal characters, as compared with all other Columbidae, though so like the rock-pigeon in most other respects⁠—the occasional reappearance of the blue colour and various black marks in all the breeds, both when kept pure and when crossed⁠—and lastly, the mongrel offspring being perfectly fertile⁠—from these several reasons, taken together, we may safely conclude that all our domestic breeds are descended from the rock-pigeon or Columba livia with its geographical sub-species.

In favour of this view, I may add, firstly, that the wild C. livia