The Courtship of Animals

by W. P. Pycraft

SOME OF FORTUNE’S FAVOURITES.

The Birds-of-Paradise have few rivals in the matter of ornament. In the centre of this plate are seen the Lesser and the King Bird-of-Paradise displaying (after G. E. Lodge). The first-named is distinguished by the enormous development of the side plumes, which can be raised high above the back. In the second, the ornaments take the form of erectile frills on each side of the breast, and strangely modified tail-feathers which end in curious discs. At the top left-hand corner is the King of Saxony’s Bird-of-Paradise; on the right is the Long-tailed Bird-of-Paradise; at the bottom of the page, from left to right, are Hunstein’s, the Six-wired, and Superb Bird-of-Paradise.

[Face page 104.

Naturally one needs to witness such a display to appreciate its beauty and its weirdness; but the wonderful sketches which my friend, Mr. G. E. Lodge, made during one of these performances, should go far towards helping the reader to visualize what really takes place.

While it would be untrue to say that the Birds of Paradise are of a more amorous, or more excitable disposition than other less resplendent birds, one cannot but be impressed with the fact that they exhibit a range of variation in the matter of feather-ornament probably unequalled, and certainly unsurpassed, by any other group of birds. From what has been observed of the few species which have been kept in confinement, they seem to enjoy no less distinction in matters of display. On this latter subject no more of importance can be said, and exigencies of space forbid any attempt to describe the exquisite beauty of coloration which a survey of all the known species reveals. It would be hardly more profitable to attempt to describe the varied character of the shields, crests, frills, streamers, which are to be met with in different species: but a glance at the accompanying illustrations will show that it would be hard, indeed, to exaggerate the splendour of the ornamentation which these birds have developed. Even here, where no indication can be given of the glowing, vivid colours, often indescribably beautiful, it is obvious that these birds well deserve their name. St. John’s imaginary Paradise would probably have been described in far more enticing language had he known of the existence of these wonderful birds.

Among all the known species the dullest is Wallace’s Bird of Paradise, the general coloration being of a dull brown hue; but even here, a pair of wing-coverts are produced into long, broad streamers, unique among birds; while the feathers of the throat and flanks are of a marvellous metallic green, the flank-feathers being produced to form a long, pointed tuft.

To what factors must we attribute the growth of these wonderful colours, these strange outgrowths, frills, and tufts, and streamers, the like of which is almost unparalleled? In a group numbering some fifty or more species there is not one that does not display some strange feature. We cannot attribute it to the environment, for in such case the results should have produced uniformity; nor can we invoke the aid of sexual selection save in a very indirect manner, and in a sense other than generally understood by this term. It seems, then, not unreasonable to suggest that they are the expression points of the internal metabolism: the manifestations of that tendency to vary which is inherent in every fibre of the organism. But no attempt shall be made to elaborate this theory till more evidence has been taken. The humming-birds, and the game-birds, are perhaps the only other groups which exhibit quite such a prodigality of ornament; of the latter, instances have already been cited.

So far the displays which have been described have been such as are confined to the use of more or less resplendent plumage. There are, however, many species which contrive to secure most startling results, not so much by the parade of coats of many colours as by grotesque changes of shape produced by wind-bags of various kinds. The Pouter-pigeon affords a case in point. This bird possesses the power of inflating the gullet to an enormous size, so as to produce a strangely distorted form, at any rate, to our eyes. The “Pouter,” it is hardly necessary to mention, is an artificial product of the “fancier,” who has taken advantage of the natural tendency, seen in the Wild Pigeon, to inflate the neck during moments of excitement. By the selection from each generation of the finest performers in his stock, the Pouter of to-day has been developed. But there are many birds which, while not even remotely related, have developed the same strange device. The most striking illustration of this kind is furnished by the Great Bustard, a bird once common on the fen-lands of Great Britain, but now, unhappily, exterminated within these islands.

The means of inflation in this case is afforded by a large thin-walled sac of a very remarkable character. Opening by a small slit just under the tongue, it is continued down the front of the neck immediately under the skin, which in this region is thickened by an accumulation of fat and blood-vessels. Between the arms of the furcula, or merry-thought, its cavity is constricted, to expand again immediately to form a pear-shaped termination. How it is filled is something of a mystery. But once inflated, the bird draws its neck downwards and backwards, so that the head is brought to rest between the shoulders and is there almost buried, partly by pressure on this curious air-cushion and partly by the erection of a number of bristle-like feathers, which in calmer moments project backwards on each side of the head. At the same time the tail is drawn forwards to lie upon the back, thus exposing a billowy mass of white feathers forming the under tail-coverts. The tips of the wing-feathers are used to hold the tail in position. Meanwhile the scapulars are set on end, and the long inner secondary quills are similarly erected. The feathered contortionist, having completed his preparations, now approaches his partner with a mincing gait, then halts before her and solemnly utters a series of low grunts like “oak, oak, oak.” Having thereby declared his passion, and commonly without gaining any answering response, he returns to his normal shape again!