Page:A narrative of travels on the Amazon and Rio Negro.djvu/82

 are constantly hopping about the bushes and twigs, picking off whatever small insects they fall in with.

The ant-thrushes are another closely allied group, which are equally abundant. They have stronger legs and very short tails, and walk more on the ground, picking up insects, especially ants, very much after the manner of poultry. When one is shot, it is often a dangerous matter to go and fetch it, for the ground generally swarms with ants, which attack an intruder most unmercifully both with stings and jaws. Many times, after a fruitless attempt, have I been obliged to leave the dead body on the field, and beat an inglorious retreat.

In all works on Natural History, we constantly find details of the marvellous adaptation of animals to their food, their habits, and the localities in which they are found. But naturalists are now beginning to look beyond this, and to sec that there must be some other principle regulating the infinitely varied forms of animal life. It must strike every one, that the numbers of birds and insects of different groups, having scarcely any resemblance to each other, which yet feed on the same food and inhabit the same localities, cannot have been so differently constructed and adorned for that purpose alone. Thus the goat-suckers, the swallows, the tyrant fly-catchers, and the jacamars, all use the same kind of food, and procure it in the same manner: they all capture insects on the wing, yet how entirely different is the structure and the whole appearance of these birds! The swallows, with their powerful wings, are almost entirely inhabitants of the air; the goat-suckers, nearly allied to them, but of a much weaker structure, and with largely developed eyes, are semi-nocturnal birds, sometimes flying in the evening in company with the swallows, but most frequently settling on the ground, seizing their prey by short flights from it, and then returning to the same spot. The fly-catchers are strong-legged, but short-winged birds, which can perch, but cannot fly with the ease of the swallows: they generally seat themselves on a bare tree, and from it watch for any insects which may come within reach of a short swoop, and which their broad bills and wide gape enable them to seize. But with the jacamars this is not the case: their bills are long and pointed—in fact, a weak kingfisher’s bill—yet they have similar habits to the preceding: they sit on branches in open parts of the forest, from thence flying after insects,