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Show 220 DOMESTIC PIGEONS. CHAP. VI. portions of tl1cir bcn,ks. So again in Java, the fan:ai: sometimes ha. o1tly fourteen caudal feathers, and the ta1l IS much los. cl vated and expanded tban in our improved birds; so that tho Java bird forms a link between a first-rate fantail and the rock-pi goon. Occa ionally a breed may be retained for some particular quality in a n arly unaltered condition in the same country, togetLor with highly modified offshoots or sub-breeds, which are valued for some distinct property. W c soc this oxcmpljfiod in England, ·where the common tumbler, which is valued only for its flight, do s not differ much from its parent-form, the Eastern tumbler; whereas tho short-faced tumbler has been prodigiously modified, from being valued., not for its flight, but for other qualiti . But the common-flying tumbler of Europe has alr acly begun to branch out into slightly different subbreeds, neh ns the common English tumbler, the Dutch roller, tho Glasgow house-tumbler, and tho long-faced beard tumbler, &c.; and in th cour e of centuries, u11loss fashions gi·eatly change, these ub-br ds will diverge through tho slow and insensible proce .. · of unconscious selection, and become modified, in a greater and oTeator degree. After a time the perfectly graduated lints, which now connect all those sub-breed ' together, will be lost, for there would b no object and much difficulty in retaining such a hof>t of intermediate sub-vari tie .. The prineiplc of divergence, together with the extinction of the many previou ly existing intermediate forms, is so important for understanding the · origin of dome tic races, as well as of sp cies in a state of natnr , that I will enlarge a little more on thi subject. Our third mai~ group includes carriers, barbs, and runt , which arc plainly related to each other, yet wond rfully distinct in several important characters. According to the view given in the last chapter, these three races have probably descended from an unknown race having an intermediate character, and this from the rock-pigeon. 'l'heir characteristic differences are believed to be due to different breeders having at an early period admired different points of structure ; and then, on the acknowledged principle of admiring extremes, havino- gone on breeding, without any thought of the future, as good birds as they could,-carrier-fanciers preferring CnAP. VI. MANNER OF FORMATION OF TilE CIIIEF RACES. 221 Ion()' beaks with much wattle,-barb-fanciers preferring short thicl{ beaks with much eye-wattle,-and runt-fanciers not caring about the beak or wattle, but only for the size and weight of the body. This process will have led to the neglect and final extinction of the earlier, inferior, and intermediate birds; and thus it has come to pass, that in Europe these three races are now so extmordinarily distinct from each other. But in the East, whence they were originally brought, the fashion bas been different, and we there sec breeds which connect tho highly modified English carrier with the rock-pigeon, and others which to a certain xtent connect carriers and runts. Looking back to the time of Aldrovandi, we find that there existed in Europe, before tho year lGOO, four breeds which were closely allied to carriers and barbs, but which competent authorities cannot now identify with our present barbs and carriers; nor can Aldrovandi's l'Unts be identified with our present runts. These four breeds certainly did not differ from eaeh other nearly so much as do our existing English carriers, barbs, and runts. All this is exactly what might have been anticipated. If we could collect al1 the pigeons which have ever lived, from before the time of the Homans to the present day, we should be able to group them in several lines, diverging from the parent rock-pigeon. Each line would consist of almost insensible steps, occasionally broken by some slightly greater variation or sport, and each would culminate in one of our present highly modified forms. Of the many former connecting links, some woulcl be found to have become ausolutcly extinct without Laving left any issue, whilst others though extinct would be seen to be the progenitors of the exit:iting races. I have heard it remarked as a strange circumstance that we occasionally hear of the local or complete extinction of domestic races, whilst we hear nothing of their origin. Ilow, it has been asked, can these losses be compensated, and more than compensated, for we know that with almost all domesticated animals tho races have largely increased in number since the time of the llomans? But on the view here given, we can understand this apparent contradiction. Tho extinction of a race within hi torieal times is an event likely to be noticed ; but its gradual and scarcely sunsible modification through unconscious selection, |