While we must accept as a well-established fact that the Humming-Birds feed on insects, demonstrated long since by naturalists, it is equally true that they are very fond of the nectar of flowers, and that this, to a certain extent, constitutes their nourishment. This is shown by the sustenance which captive Humming-Birds receive from honey and other sweet substances, food to which a purely insectivorous bird could hardly adapt itself.
Notwithstanding their diminutive size the Humming-Birds are notorious for their aggressive disposition. They attack with great fury anything that excites their animosity, and maintain constant warfare with whatever is obnoxious to them, expressly the Sphinxes or Hawk-Moths. Whenever one of these inoffensive moths, two or three times the size of a Humming-Bird, chances to come too early into the garden and encounters one of these birds, he must give way or meet with certain injury. At sight of the insect the bird attacks it with his pointed beak with great fury. The Sphinx, overcome in this unlooked-for attack, beats a retreat, but, soon returning to the attractive flowers, is again and again assaulted by its infuriated enemy. Certain destruction awaits these insects if they do not retire from the field before their delicate wings, lacerated in these attacks, can no longer support them, and they fall to the ground to perish from other enemies.
In other things the Humming-Bird also shows itself all the more impertinent and aggressive that it is small and weak. It takes offence at everything that moves near it. It attacks birds much larger than itself, and is rarely disturbed or molested by those it thus assails. All other birds must make way. It is possible that in some of these attacks it may be influenced by an instinctive prompting of advantages to be gained, as in the case of the spider, in whose nets they are liable to be entangled, and whose
webs often seriously incommode them. When a Humming-Bird perceives a spider in the midst of its net, it rarely fails to make an attack, and with such rapidity that one cannot follow the movement, but in the twinkling of an eye the spider has disappeared. This is not only done to small spiders, which doubtless they devour, but also to others too large to be thus eaten.
Not content with thus chastising small enemies, the Humming-Bird also contends with others far more powerful, and which give them a good deal of trouble. They have been known to engage in an unequal contest with the Sparrow-Hawk, yet rarely without coming off the conquerors. In this strife they have the advantage of numbers, their diminutive size, and the rapidity and the irregularity of their own movements. Several unite in these attacks, and, in rushing upon their powerful enemy, they always aim at his eyes. The Hawk soon appreciates his inability to contend with these tormenting little furies, and beats an ignominious retreat.
Advantage is taken of this aggressive disposition of these birds, by the hunter, to capture them. In their combats with one another, or in their rash attacks upon various offensive objects, even upon the person of the snarer himself, they are made prisoners through their own rashness and reckless impetuosity.
In enumerating the prominent characteristics of this remarkable family, we should not omit to refer to the lavish profusion of colors of every tint and shade, excelling in lustre and brilliancy even the costliest gems, with which Nature has adorned their plumage. And not only are nearly all the birds of this group thus decked out with hues of the most dazzling brightness and splendor, when alive and resplendent in the tropical sun, but many also display the most wonderfully varying shades and colors, according to the position in which they are presented to the eye. The sides of the fibres of each feather are of a different color from the surface, and change as seen in a front or an oblique direction, and while living, these birds, by their movements, can cause these feathers to change very suddenly to very different hues. Thus the Selasphorus rufus can change in a twinkling the vivid fire-color of its expanded throat to a light green, and the species known as the Mexican Star (Cynanthus lucifer) changes from a bright crimson to an equally brilliant blue.
The nests and the eggs of the Humming-Birds, though in a few exceptional cases differing as to the form and position of the former, are similar, so far as known, in the whole family. The eggs are always two in number, white and unspotted, oblong in shape, and equally obtuse at either end. The only differences to be noticed are in the relative variations in size. The nests are generally saddled upon the upper side of a horizontal branch, are cup-like in shape, and are largely made up of various kinds of soft vegetable down, covered by an outward coating of lichens and mosses fastened upon them by the glue-like saliva of the bird. In T. colubris the soft inner portion of the nest is composed of the delicate downy covering of the leaf-buds
of several kinds of oaks. In Georgia the color of this down is of a deep nankeen hue, but in New England it is nearly always white. At first the nest is made of this substance alone, and the entire complement of eggs, never more than two, is sometimes laid before the covering of lichens is put on by the male bird, who seems to amuse himself with this while his mate is sitting upon her eggs.
Genus STELLULA, Gould.