. Animal Life and the World of Nature; A magazine of Natural History. 206 Animal Life [Garduelis carduelis and G. caniceps) encounter each other; and where the Blue Rollers of India and Burma (Coracias indicus and C. affinis) come into contact, to say nothing of many other cases. It is a question, however, whether this can be called true hybridism, since it may reasonably be argued that species which have got no further in separation than a different plumage are not as yet fully distinct, but rather comparable to the colour- varieties in our domesticated birds. That the intermediate birds repr
. Animal Life and the World of Nature; A magazine of Natural History. 206 Animal Life [Garduelis carduelis and G. caniceps) encounter each other; and where the Blue Rollers of India and Burma (Coracias indicus and C. affinis) come into contact, to say nothing of many other cases. It is a question, however, whether this can be called true hybridism, since it may reasonably be argued that species which have got no further in separation than a different plumage are not as yet fully distinct, but rather comparable to the colour- varieties in our domesticated birds. That the intermediate birds represent the ancestors of the two forms does not seem at all probable, because the evidence is in favour of colour-varieties appearing suddenly, and not by gradations from an intermediate type. Thus, there are two forms of the common Peacock, the typical Pavo crista his and the black-winged Pavo nigripennis, but there has never been an intermediate ancestor to these, for we know for a fact that the black-winged form, like the albino one, arises quite suddenly from the ordinary bird. It may also be remarked that the free interbreeding of forms or species separated only by colour is a fatal blow to the common theory that colour-differences are " recognition-marks" by which birds of a feather are enabled to flock together. The fertility of undoubted hybrids—between species where other points combine with colour to make a distinction admitted by everyone—is still very widely disbelieved. And there is some reason for the disbelief, since it appears to be the case that the commonest bird-hybrids, the "mules" between various British Finches and the Canary, are usually barren, though they will pair, lay, and sit in the most exemplary way, a hen "mule" being a notoriously good nurse for young canaries. Another common hybrid, that between the Fowl . .,'>' and Pheasant, is also well ^dflK known to be sterile, as likewise ^3! are those between very distinc
Size: 2076px × 1204px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookpublisherlondo, bookyear1902
