About 500 distinct species of humming-birds are known.
Humming-birds surpass all others in the wondrous beauty of their plumage, which depends not so much on colour as metallic lustre reflecting all the hues of the most precious stones—amethyst, ruby, sapphire, emerald, and topaz gleaming and sparkling from their bodies with a fire and intensity truly marvellous. "In some cases," as Professor Newton aptly describes it, "this radiance beams from the brow, in some it glows from the throat, in others it shines from the tail-coverts, in others it sparkles from the tips of elongated feathers that crest the head or surround the neck as with a frill, while again in others it may appear as a luminous streak across the cheek.... The feathers that cover the upper parts of the body very frequently have a metallic lustre of golden green, which in other birds would be thought sufficiently beautiful, but in the [humming-birds] its sheen is overspread by the almost dazzling splendour that radiates from the spots where Nature's lapidary has set her jewels."
Besides this brilliancy of colour and variety in form—variety due to the development of these crests and frills, or to the forking and elongation of the tail-feathers—still further changes are brought about by the modification of the bill, which may be produced into a long straight style, longer than the body of the bird, or turned up like that of the avocet or down like that of the curlew. These changes are adaptations to the bird's methods of feeding, some seeking their food from the long tubular corollas of flowers, and requiring, therefore, very elongated beaks, others from more open and easily accessible flowers, whilst others hunt among leaves, especially the under-surfaces, the quarry consisting mainly of insects attracted by the honey secreted by the flowers, or those living on the leaves. Not only the beak but the tongue also has undergone great modification in this group, its outer sheath curling up on each side into a thin scroll, so as to form a pair of tubes, the exact use of which is unknown. The wings, like those of the swift, have undergone a certain amount of change in the relative proportion of the several regions, and in the form and number of the quill-feathers, whilst the legs have become considerably reduced in size. In some species each leg is surrounded by a little tuft of down, which may be black, brown, or snow-white in colour. In size these birds vary from 8 inches to scarcely more than 3 inches.
"The beautiful nests of humming-birds," writes Professor Newton, "than which the fairies could not have conceived more delicate ... will be found on examination to be very solidly and tenaciously built, though the materials are generally of the slightest—cotton-wool, or some vegetable down, and spiders' webs. They vary greatly in form and ornamentation—for it would seem that the portions of lichen which frequently bestud them are affixed to their exterior with that object, though probably concealment was the original intention. They are mostly cup-shaped; and the singular fact is on record, that in one instance, as the young grew, the walls were heightened by the parents, until at last the nest was more than twice as big as when the eggs were laid and hatched."
CHAPTER XI.
PARROTS, CUCKOOS, AND PLANTAIN-EATERS.
Parrots.
"The art of taming wild animals," writes Mr. Jenks in his "History of Politics," "and making them serve the purposes of man, is one of the greatest discoveries of the world." He holds—and there can be little question as to its reasonableness—"that the domestication of animals converted the savage pack into the patriarchal tribe," and that the earliest domesticated animals were pets. How great a share, then, Parrots may have had in this civilisation and advancement no man can tell, for it is impossible to say how long these beautiful birds may have been esteemed as pets, or how early they were introduced to the notice of the civilised peoples of past generations. Certain it is, however, that for more than 2,000 years they have been held in the highest esteem.
Modern discovery has added enormously to the list of known parrots, so that to-day more than 500 different species have been described, and these may be divided into Nestors, Lories, Cockatoos, Cockateels, Macaws, and Kakapos.