There is clear distinction between wild rock pigeons, domestic pigeons and feral pigeons.
Some people speak of ferals as “free-flying domestics”, but we have seen that feral pigeons have developed themselves as being independent of human interference. However, you will see feral pigeons often referred to as Columba livia domestica, though this is a combination that is, nomenclaturally, wholly unrecognised. This is because the International Code of Zoological Nomenclature pertains only to “natural” biological, and not to those created by human selection. For Feral pigeons it is not suitable anyway, because they are not created by human selection. Some authors employ the convention of the variety (C. livia var. domestica), which is not a formal category in zoological nomenclature either. And the same for form or forma; C. livia f. domestica is invalid according to the rules of the Code.
Knowing all of this, how to refer to feral pigeons then? To begin with, since feral pigeons are not domestic pigeons, they should not be called domestic pigeons. Not vernacularly or otherwise. If someone will someday propose to call them “C. livia ferina” or “C. livia urbana”, that are names to avoided as well, because feral pigeons have multiple origins. The only valid scientific name for feral pigeons is Columba livia, after there original ancestor. And the preferred vernacular name is feral pigeon.
In the 10th edition of his Systema Naturea, Linnaeus described his ‘blue pigeon’ after Aldrovandi’s Oenas s. Vinago. According to Linnaeus the species was bluish-grey with a glossy green neck and a black bar on his tail and wings. (“caerulescens, collo supra viridi-nitente, fascia alarum apiceque caudae nigricante”). He named this pigeon Columba oenas, and that was quite a good description of the stock dove indeed.
However, Linnaeus did not mean the stock dove specific. He meant all pigeons, wild and tame, what in his opinion meet this description. So both the stock dove and the rock pigeon and all tame pigeons with a comparable plumage colour. According to him it was all the same species. However, within the species oenas Linnaeus distinguished specifically the so called tame pigeons or dovecote pigeons. This variety he called Columba domestica. Besides their colour these pigeons didn’t differ at all from the ‘wild form’.
Next Linnaeus described a few domesticated breeds as if they where original forms (species). Because he mentioned them apart from his oenas and domestica it is obvious that he didn’t know these pigeons actually were domesticated forms. Also in the 12th edition of his Systema Naturea he still didn’t know and among others he mentioned as being original species the following pigeons:
Between 1788 and 1793 Gmelin’s revision of Linnaeus’ 13th edition was published. In Tom I.2 (1789) Gmelin mentioned Columba oenas as well but he did mean the Stock dove only. And he also described Columba domestica, but now separated from oenas.
According to Gmelin this ‘Common Pigeon’ is ash-grey with a white rump and a black bar on the tail and wings (“cinerea, uropygio albo, alurum fascia, caudaeque apice nigricante”). Just like Linnaeus Gmelin described next a few related, but distinguishable forms of which we know nowadays it are domesticated breeds. It’s remarkable that he discerned these forms (20 in total) as varieties of Columba domestica. This may indicate that Gmelin knew that all those pigeons derived from each other. But at least he knew they had nothing to do with the stock dove.
The first variety within domestica he started with is Columba livia. Most important difference between domestica and livia, according to Gmelin, is the double bar on the wings (“alarum fascia duplici”). Who originated from who was still not yet completely clear. However, by this Gmelin was the first who had scientifically named the rock pigeon. If he really meant the wild rock pigeon, or tame pigeons with the same colour, is not clear but that does not matter. In those days tame pigeons were often kept in a semi wild state so that it was not easy to tell the difference and they are the same species anyway.