Moreover, I don’t believe that any ornithologist would place the English provider, the short-faced tumbler, the runt, the barb, pouter, and fantail in the identical genus; extra particularly as in each of these breeds several truly-inherited sub-breeds, or species as he might need referred to as them, might be shown him. If the several breeds are not varieties, and have not proceeded from the rock-pigeon, they will need to have descended from a minimum of seven or eight aboriginal stocks; for it is unattainable to make the present home breeds by the crossing of any lesser number: how, for example, could a pouter be produced by crossing two breeds except one of many parent-stocks possessed the characteristic huge crop? The proportional width of the gape of mouth, the proportional length of the eyelids, of the orifice of the nostrils, of the tongue (not at all times in strict correlation with the size of beak), the size of the crop and of the upper part of the œsophagus; the development and abortion of the oil-gland; the variety of the primary wing and caudal feathers; the relative length of wing and tail to one another and to the physique; the relative length of leg and of the ft; the variety of scutellæ on the toes, the event of skin between the toes, are all points of structure which are variable.
An argument, as it appears to me, of nice weight, and applicable in a number of different cases, is, that the above-specified breeds, though agreeing typically in constitution, habits, voice, colouring, and in most components of their structure, with the wild rock-pigeon, but are certainly extremely abnormal in other components of their structure: we could look in vain throughout the whole great household of Columbidæ for a beak like that of the English provider, or that of the quick-faced tumbler, or barb; for reversed feathers like those of the jacobin; for a crop like that of the pouter; for tail-feathers like these of the fantail. Thirdly, those characters that are primarily distinctive of each breed, as an example the wattle and size of beak of the service, the shortness of that of the tumbler, and the number of tail-feathers within the fantail, are in every breed eminently variable; and the explanation of this fact shall be obvious when we come to deal with of selection.
The fantail has thirty or even forty tail-feathers, as a substitute of twelve or fourteen, the conventional quantity in all members of the great pigeon household; and these feathers are saved expanded, and are carried so erect that in good birds the top and tail contact; the oil-gland is quite aborted. The Jacobin has the feathers so much reversed alongside the again of the neck that they type a hood, and it has, proportionally to its dimension, a lot elongated wing and tail feathers. I have discussed the probable origin of home pigeons at some, yet quite inadequate, length; as a result of when i first kept pigeons and watched the a number of varieties, figuring out effectively how true they bred, I felt absolutely as much problem in believing that they may ever have descended from a common mum or dad, as any naturalist may in coming to a similar conclusion in regard to the various species of finches, or other giant groups of birds, in nature. Altogether not less than a rating of pigeons is likely to be chosen, which if shown to an ornithologist, and he have been advised that they were wild birds, would certainly, I think, be ranked by him as well-defined species. Some details in regard to the colouring of pigeons nicely deserve consideration.
Youatt, who was most likely better acquainted with the works of agriculturalists than virtually another individual, and who was himself an excellent judge of an animal, speaks of the principle of choice as “that which permits the agriculturist, not solely to change the character of his flock, but to alter it altogether. It’s the magician’s wand, by way of which he might summon into life whatever type and mould he pleases.” Lord Somerville, talking of what breeders have performed for sheep, says:-“It would seem as if they had chalked out upon a wall a type excellent in itself, after which had given it existence.” That almost all skilful breeder, Sir John Sebright, used to say, with respect to pigeons, that “he would produce any given feather in three years, but it might take him six years to obtain head and beak.” In Saxony the importance of the principle of selection in regard to merino sheep is so totally recognised, that men observe it as a trade: the sheep are placed on a desk and are studied, like an image by a connoisseur; this is completed thrice at intervals of months, and the sheep are each time marked and classed, in order that the easiest could ultimately be selected for breeding.