Page:Encyclopædia Britannica, Ninth Edition, v. 3.djvu/791

EGGS,] BIRDS 773 watch them as they develop to maturity, we may compre hend the way in which every part of a complicated struc ture is successively built up, but if we take not the trouble to know their effect on the economy of the creatnre we as naturalists have done but half our task and abandon our labour when the fulness of reward is coming upon us. The field-naturalist, properly instructed, crowns the work of the comparative anatomist and the physiologist, though without the necessary education he is little more than an empiric, even should he possess the trained cunning of the savage on whose knowledge of the habits of wild animals depends his chance of procuring a meal. eries Perhaps the greatest scientific triumph of oologists lies - in their having fully appreciated the intimate alliance of the Limicolce (the great group of Snipes and Plovers) with the Gavice (the Gulls, Terns, and other birds more distantly connected with them) before it was recognized by any pro fessed taxonomist, L Herminier, whose researches have been much overlooked, excepted; though to such an one was given the privilege of placing that affinity beyond cavil (Huxley, Proc. Zool. Soc. 18G7, pp. 426, 456-458 ; cf. Ibis, 1868, p. 92). In like manner it is believed that oologists first saw the need of separating from the true Passeres several groups of birds that had for many years been un hesitatingly associated with that very uniform assemblage. Diffidence as to their own capacity for meddling with mat ters of systematic arrangement may possibly have been the cause which deterred the men who were content to brood over birds eggs from sooner asserting the validity of the views they held. Following the example furnished by the objects of their study, they seem to have chiefly sought to hide their offspring from the curious eye and if such was their design it must be allowed to have been admirably successful. In enthusiastic zeal for the prosecution of their favourite researches, however, they have never yielded to, if they have not surpassed, any other class of naturalists. If a storm-swept island, only to be reached at the risk of life, held out the hope of some oological novelty there was the egg-collector (Faber, Isis, xx. pp. 633-688 ; Proctor, Naturalist, 1838, pp. 411, 412). Did another treasure demand his traversing a burning desert (Tristram, Ibis, 1859, p. 79) or sojourning for several winters within the wildest wastes of the Arctic Circle (Wolley, Ibis, 1859, pp. 69-76; 1861, pp. 92-106; Kennicott, Rep. Smithson. Inst. 1862, pp. 39, 40), he endured the necessary hard ships to accomplish his end, and the possession to him of an empty shell of carbonate of lime, 1 stained or not (as the case might be) by a secretion of the villous membrane of the parent s uterus, was to him a sufficient reward. Taxo- nomers, however, have probably been right in not attach ing too great an importance to such systematic characters as can be deduced from the eggs of birds, but it would have been better had they not insisted so strongly as they have done on the infallibility of one or another set of char acters, chosen by themselves. Oology taken alone proves to be a guide as misleading as any other arbitrary method of classification, but combined with the evidence afforded by due study of other particularities, whether superficial or deep-seated, it can scarcely fail in time to conduct us to an ornithological arrangement as nearly true to Nature as we may expect to achieve. The first man of science who seems to have given any special thought to oology, was the celebrated Sir Thomas Browne, of Norwich, who already in 1681, when visited by John Evelyn (from whose diary we learn the fact), had assigned a place in his cabinet of rarities to a collection of birds eggs. The next we hear of is that Count of Marsigli 1 A small proportion of carbonate of magnesia and phosphate of lime and magnesia also enters into its composition. who early in the eighteenth century explored, chiefly for this kind of investigation, the valley of the Danube a region at that time, it is almost unnecessary to remark, utterly unknown to naturalists. But there is no need to catalogue the worthies of this study. As they approach our own day their number becomes far too great to tell, and if very recently it has seemed to dwindle the reason is probably at hand in the reflection that most of the greatest prizes have been won, while those that remain to reward the aspiring appear to be just now from one cause or another almost out of reach. Perhaps at the present time the Birds- of-Paradise and their allies form the only group of any recognized distinctiveness and extent of whose eggs we know absolutely nothing though there are important iso lated forms, such as Atrickia, Heterolocha, and others, con cerning the eggs as well as the breeding habits of which our ignorance is absolute, and the species of many families that have hitherto defied the zeal of oologists are very numerous, These last, however, though including some common and some not very uncommon British birds, possess in a general way comparatively little interest, since, the eggs of their nearest allies being well known, we cannot expect much to follow from the discovery of the recluses, and it is only to the impassioned collector that the obtain ing of such desiderata will afford much satisfaction. The first thing which strikes the eye of one who be- Varied holds a large collection of egg-shells is the varied hues of ^ ues 1 the specimens. Hardly a shade known to the colourist is " ^ not exhibited by one or more, and some of these tints have their beauty enhanced by the glossy surface on which they are displayed, by their harmonious blending, or by the pleasing contrast of the pigments which form markings as often of the most irregular as of regular shape. But it Forms < would seem as though such markings, which a very small niar ^ n ! amount of observation will shew to have been deposited on the shell a short time before its exclusion, are primarily and normally circular, for hardly any egg that bears mark ings at all does not exhibit some spots of that form, but that in the progress of the eggs through that part of the oviduct in which the colouring matter is laid on many of them become smeared, blotched, or protracted in some par ticular direction. The circular spots thus betoken the deposition of the pigment while the egg is at rest, the blurred markings show its deposition while the egg is in motion, and this motion would seem often to be at once onward and rotatory, as indicated by the spiral markings not un commonly observable in the eggs of some Birds-of-prey and others the larger end of the egg (when the ends differ in form) making way for the smaller. 2 At the same time the eggs of a great number of birds bear, beside these last and superimposed markings, more deeply-seated stains, generally of a paler and often of an altogether different hue, and these are evidently due to some earlier dyeing process. The peculiar tint of the ground-colour, though Ground commonly superficial, if not actually congenital with the colour, formation of the shell, would appear to be suffused soon after. The depth of colouring whether original or super vening is obviously dependent in a great measure on the constitution or bodily condition of the parent. If a bird, bearing in its oviduct a fully-formed egg, be captured, that egg will speedily be laid under any circumstances of in convenience to which its producer shall be subjected, but such an egg is usually deficient in coloration fright and 2 That the larger end is protruded first was found on actual experi ment fry Mr Bartlett, Superintendent of the Gardens of the Zoological Society, to be the casa commonly, but as an accident the position may be sometimes reversed, and this will most likely account for the occa sional deposition of markings on the smaller instead of the larger end as not uu frequently shown in eggs of the Sparrow-hawk (Accipiter

nisus). The head of the chick is always formed at the larger end.