The exercise of vocal power among birds seems to be complementary to the development of accessory plumes and ornaments. All our finest singing birds are plainly coloured, with no crests, neck or tail plumes to display. The gorgeously ornamented birds of the tropics have no song, and those which expend much energy in display of plumage, as the turkey and peacocks, have comparatively an insignificant development of voice.[76] The extraordinary manner in which birds display their plumage at the time of courting is well known. Let us take one example--the courtship of the Argus pheasant. This bird is noted for the extreme beauty of the male's plumage. Its courtship has been beautifully observed by H.O. Forbes--[77] "It is the habit of this bird to make a large circus, some ten or twelve feet in diameter, in the forest, which it clears of every leaf and twig and branch, till the ground is perfectly swept and garnished. On the margin of this circus there is invariably a projecting branch or high arched rest, at a few feet elevation from the ground on which the female bird takes its place, while in the ring the male--the male bird alone possesses great decoration--shows off all its magnificence for the gratification and pleasure of his consort, and to exalt himself in her eyes." In this picture we have all the characteristic features of the display of personal beauty in which many birds delight. Any one may see such performances for themselves. The male chaffinch, for instance, will place himself in front of the female that she may admire at her ease his red throat and blue head; the bullfinch swells out his breast to display the crimson feathers, twisting his black tail from side to side; the goldfinch sways his body, and quickly turns his slightly expanded wings first to one side, then to the other, with a golden flashing effect.[78] Even birds of less ornamental plumage are accustomed to strut and show themselves off before the females. 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.[79] It seems certain that this aesthetic display is conscious and pre-meditated; for while most pheasants parade before their females, two of the species--the _Crossoptilon auritum_ and the _Phasianus Wallichii_--which are of dull colour, refrain from doing so, being apparently conscious of their modest livery.[80]