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YIL 20of such a See also:species there would be no need 41 anvtbing further to ensure success—the terror of the See also:nest-owner ae .,eeing her See also:home invaded by a See also:hawk-like See also:giant, and some of her treasures tossed out, would be enough to stir her motherly feelings so deeply that she would without misgiving, if not with joy that something had been spared to her, resume the See also:duty of See also:incubation so soon as the danger was past. But with other species it may be, and doubtless is, different. Here assimilation of the introduced See also:egg to those of the rightful owner may be necessary, for there can hardly be a doubt as to the truth of Dr Baldamus's theory as to the See also:object of the assimilation being to render the See also:cuckoo's egg "less easily recognized by the See also:foster-parents as a substituted one." It is especially desirable to point out that there is not the slightest ground for imagining that the cuckoo, or any other See also:bird, can voluntarily See also:influence the See also:colour of the egg she is about to See also:lay. Over that she can have no See also:control, but its destination she can determine. It would seem also impossible that a cuckoo, having laid an egg, should look at it, and then decide from its See also:appearance in what bird's nest she should put it. That the colour of an egg-See also:shell can be in some mysterious way affected by the See also:action of See also:external See also:objects on the perceptive faculties of the See also:mother is a notion too See also:wild to be seriously entertained. Consequently, only one explanation of the facts can here be suggested. Every one who has sufficiently studied the habits of animals will admit the influence of See also:heredity. That there is a reasonable See also:probability of each cuckoo most commonly putting her eggs in the nest of the same species of bird, and of this See also:habit being transmitted to her posterity, does not seem to be a very violent supposition. Without attributing any wonderful sagacity to her, it does not seem unlikely that the cuckoo which had once successfully foisted her egg on a See also:reed-See also:wren or a titlark should again seek for another reed-wren's or another titlark's nest (as the See also:case may be), when she had another egg to dispose of, and that she should continue her practice from one See also:season to another. It stands on See also:record (Zoologist, 1873, p. 3648) that a pair of wag-tails built their nest for eight or nine years See also:running in almost exactly the same spot, and that in each of those years they fostered a See also:young cuckoo, while many other cases of like See also:kind, though not perhaps established on so See also:good authority, are believed to have happened. Such a habit could hardly fail to become hereditary, so that the daughter of a cuckoo which always put her egg into a reed-wren's, titlark's or See also:wagtail's nest would do as did her mother. Furthermore it is unquestionable that, whatever variation there may be among the eggs laid by different individuals of the same species, there is a strong See also:family likeness between the eggs laid by the same individual, even at the See also:interval of many years, and it can hardly be questioned that the eggs of the daughter would more or less resemble those of her mother. Hence the supposition may be fairly credited that the habit of laying a particular See also:style of egg is also likely to become hereditary. Combining this supposition with that as to the cuckoo's habit of using the nest of the same species becoming hereditary, it will be seen that it requires only an application of the principle of natural selection to show the probability of this principle operating in the course of See also:time to produce the facts asserted by the See also:anonymous Solognot of the 18th See also:century, and by Dr Baldamus and others since. The particular gens of cuckoo which inherited and transmitted the habit of depositing in the nest of any particular species of bird eggs having more or less resemblance to the eggs of that species would prosper most in those members of the gens where the likeness was strongest, and the other members would (ceteris paribus) in time be eliminated. As already shown, it is not to be supposed that all species, or even all individuals of a. species, are duped with equal ease. The operation of this kind of natural selection would be most needed in those cases where the species are not easily duped—that is, in those cases which occur the least frequently. Here it is we find it, for observation shows that eggs of the cuckoo deposited in nests of the red-backed See also:shrike (Lanius collurio), of the See also:bunting (Emberiza miliaria), and of the icterine See also:warbler approximate in their colouring to eggs of those species—species in whose nests the cuckoo rarely (in comparison with others) deposits eggs. S2 Of species which are more easily duped, such as the hedge-See also:sparrow, mention has already been made. More or less nearly allied to the See also:British cuckoo are many other forms of the genus from various parts of See also:Africa, See also:Asia and their islands, while one even reaches See also:Australia. In some cases the See also:chief difference is said to See also:lie in the diversity of See also:voice—a See also:character only to be appreciated by those acquainted with the living birds, and though of course some regard should be paid to this distinction, the possibility of birds using different "dialects" according to the locality they inhabit must make it a slender specific diagnostic. All these forms are believed to have essentially the same habits as the British cuckoo, and, as regards See also:parasitism the same is to be said of the large cuckoo of See also:southern See also:Europe and See also:North Africa (Cbccystes glandarius), which victimizes pies (See also:Pica mauritanica and Cyanopica cooki) and crows (See also:Corvus cornix). True it is that an instance of this species, commonly known as the See also:great spotted cuckoo, having built a nest and hatched its young, is on record, but the later observations of others tend to See also:cast doubt on the credibility of the See also:ancient See also:report. It is worthy of remark that the eggs of this bird so closely resemble those of one of the pies in whose' nest they have been found, that even See also:expert zoologists have been deceived by them, only to discover the truth when the cuckoo's embryo had been extracted from the supposed See also:pie's egg. This species of cuckoo, easily distinguishable by its large See also:size and See also:long See also:crest, has more than once made its appearance as a straggler in the British Isles. Equally parasitic are many other cuckoos, belonging chiefly to genera which have been more or less clearly defined as Cacomantis, Chrysococcyx, Eudynamis, Oxylophus, Poly phasia and Surniculus, and inhabiting parts of the Ethiopian, See also:Indian and Australian regions ;1 but there are certain aberrant forms of Old See also:World cuckoos which unquestionably do not shirk parental responsibilities. Among these especially are the birds placed in or allied to the genera Centro pus and Coua—the former having a wide See also:distribution from See also:Egypt to New See also:South See also:Wales, living much on the ground and commonly called See also:lark-heeled cuckoos; the latter bearing no See also:English name, and limited to the See also:island of See also:Madagascar. These build a nest, not perhaps in a highly finished style of See also:architecture, but one that serves its end. Respecting the cuckoos of See also:America, the See also:evidence; though it has been impugned, is certainly enough to clear them from the See also:charge which attaches to so many of their brethren of the Old World. There are two species very well known in parts of the See also:United States and some of the See also:West Indian Islands (Coccyzus ,tmericanus and C. erythrophthalmus), and each of them has occasionally visited Europe. They both build nests—remarkably small structures when compared with those of other birds of their size—and faithfully incubate their delicate See also:sea-See also:green eggs. In the south-western states of the See also:Union and thence into Central America is found another curious See also:form of cuckoo (Geococcyx)—the chaparral-See also:cock of See also:northern and paisano of southern settlers. The first of these names it takes from the See also:low brushwood (chaparral) in which it chiefly dwells, and the second is said to be due to its See also:pheasant-like (faisan corrupted into paisano, properly a countryman) appearance as it runs on the ground. Indeed, one of the two species of the genus was formerly described as a Phasianus. They both have See also:short wings, and seem never to See also:fly, but run with great rapidity. Returning to arboreal forms, the genera Neomorphus, Diplopterus, Saurothera and Piaya (the last two commonly called See also:rain-birds, from the belief that their cry portends rain). may be noticed—all of them belonging to the Neotropical region; but perhaps the most curious form of See also:American cuckoos is the See also:ani (Crotophaga), of which three species ,inhabit the same region. The best-known species (C. ani) is fond throughout the See also:Antilles and on the opposite See also:continent. In most of the British colonies it is known as the See also:black See also:witch, and is accused of various malpractices—it being, in truth, a perfectly harmless if not a beneficial bird. As regards its See also:propagation this aberrant form of cuckoo departs in one direction Evidence tends to show that the same is to be said of the curious channel-See also:bill (Scythrops novae-hollandiae), though See also:absolute See also:proof seems to be wanting.from the normal habit of birds, for several See also:females,' unite to lay their eggs in one nest. ' It is evident that incubation is carried on socially, since an intruder on approaching the See also:rude nest will disturb perhaps See also:half a dozen of its See also:sable proprietors, who, loudly complaining, seek safety either in the leafy branches of the See also:tree that holds it, or in the nearest available covert. with all the See also:speed that their feeble See also:powers of See also:flight permit. (A. N.) CUCKOO-See also:SPIT, a frothy secretion found upon See also:plants, and produced by the immature nymphal See also:stage of various plant-lice of the See also:familiar Cercopidae and Jassidae, belonging to the homopterous See also:division of the See also:Hemiptera, which in the adult See also:condition are sometimes called See also:frog-hoppers. Additional information and CommentsThere are no comments yet for this article.
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