Every one has seen our pigeons and doves courteously salute their mates. Many male birds execute dances and courting parades before their females. Thus, for example, do the Tetras phasaniellus of North America, herons (Cathartes jota), vultures, etc. The male of the red-wing struts about before his female, sweeping the ground with his tail and acting the dandy.[10] The crested duck raises his head gracefully, straightens his silky aigrette, or bows to his female, while his throat swells and he utters a sort of gutteral sound.[11] The male chaffinch places himself in front of the female, that she may admire at her ease his red throat and blue head.[12]
All this æsthetic display is quite intentional and premeditated; for while many pheasants and gallinaceous birds parade before their females, two pheasants of dull colour, the Crossoptilon auritum and the Phasianus Wallichii, refrain from doing so,[13] being apparently conscious of their modest livery.
Birds often assemble in large numbers to compete in beauty before pairing. The Tetras cuspido of Florida and the little grouse of Germany and Scandinavia do this. The latter have daily amorous assemblies, or cours d’amour, of great length, which are renewed every year in the month of May.[14]
Certain birds are not content with their natural ornaments, however brilliant these may be, but give the rein to their æsthetic desire in a way that may be called human. Mr. Gould assures us that some species of humming-birds decorate the exterior of their nests with exquisite taste, making use of lichens, feathers, etc. The bower-birds of Australia (Chlamydera maculata, etc.) construct bowers on the ground, ornamented with feathers, shells, bones, and leaves. These bowers are intended to shelter the courting parades, and both males and females join in building them, though the former are more zealous in the work.[15] But in this erotic architecture the palm is carried off by a bird of New Guinea, the Amblyornis inornata, made known to us by M. O. Beccari.[16] This bird of rare beauty, for it is a bird of Paradise, constructs a little conical hut to protect his amours, and in front of this he arranges a lawn, carpeted with moss, the greenness of which he relieves by scattering on it various bright-coloured objects, such as berries, grains, flowers, pebbles, and shells. More than this, when the flowers are faded, he takes great care to replace them by fresh ones, so that the eye may be always agreeably flattered. These curious constructions are solid, lasting for several years, and probably serving for several birds. What we know of sexual unions among the lower human races suffices to show how much these birds excel men in sexual delicacy.
Every one is aware that the melodious voice of many male birds furnishes them with a powerful means of seduction. Every spring our nightingales figure in true lyric tournaments. Magpies, who are ill-endowed from a musical point of view, endeavour to make up for this organic imperfection by rapping on a dry and sonorous branch, not only to call the female, but also to charm her; we may say, in fact, that they perform instrumental music. Another bird, the male of the weaver-bird, builds an abode of pleasure for himself, where he goes to sing to his companion.[17]
Audubon has made one observation in regard to Canadian geese which is in every point applicable to the human species. The older the birds are, he says, the more they abridge the preliminaries of their amours. Their poetic and æsthetic sense has become blunted, and they go straight to their object.
Wherever amongst the animal species supremacy in love is obtained by force, the male, nearly always the more ardent, has necessarily become, through the action of selection, larger, stronger, and better armed than the female. Such is in reality the case in regard to the greater number of vertebrates; certain exceptions, however, exist, and naturally these are chiefly found among birds, as they are more inclined than other types to put a certain delicacy in their sexual unions. With many species of birds, indeed, the female is larger and stronger than the male. It is well known to be the same with certain articulates, and these facts authorise us to admit that there is no necessary correlation between relative weakness and the female sex. Must we therefore conclude, with Darwin, that the females of certain birds owe their excess of size and height to the fact that they have formerly contested also for the possession of the males? We may be allowed to doubt it. Almost universally, whether she is large or small, the female is less ardent than the male, and in the amorous tragi-comedy she generally plays, from beginning to end, a passive rôle; in the animal kingdom, as well as with mankind, amazons are rare.
Among birds and vertebrates generally the male is much more impetuous than the female, and therefore he has no difficulty in accepting for the moment any companion whatever.[18] This uncontrollable ardour sometimes even urges the males to commit actual attempts on the safety of the family. Thus it happens that the male canary (Fringilla canaria) persecutes his female while she is sitting, tears her nest, throws out the eggs, and, in short, tries to excite his mate to become again a lover, forgetting that she is a mother. In the same way our domestic cock pursues the sitting hen when she leaves her eggs in order to feed.[19]
With the cousins-german of man, the mammals, sexual psychology has a general resemblance to that of birds, but more often it is far less delicate. And besides this, the sexual customs are naturally less refined in proportion as the nervous centres of the species are less perfected. Thus the stupid tatoways meet by chance, smell each other, copulate and separate with the greatest indifference. Our domestic dog himself, although so civilised and affectionate, is generally as gross in his amours as the tatoway.
With birds, as we have seen, the law of battle plays an important part in sexual selection; but it is often counter-balanced by other less brutal influences. This is rarely the case in regard to mammals, with whom especially the right of the strongest regulates the unions. The law of battle prevails among aquatic as well as land mammals. The combats of the male stags, in the rutting season, are celebrated. The combatants have been known to succumb without being able to disentangle their interlocked antlers; but seals and male sperm-whales fight with equal fury, and so also do the males of the Greenland whale.[20]