count of the prodigious numbers of field-mice they destroy. Yet the farmers kill these benefactors, and nail their skins upon their sheddoors as trophies and admonitions. This is bad enough, even though it be done in ignorance and not in malice. Toads and creeping things are pursued by numerous wild birds—the snake-eagle, the secretary, the curious South American cuckoos called saurothers, and many other feathered foes. The dumb host of fishes finds eager hunters among the birds, even more than among men. Cormorants and pelicans, gulls and sea-swallows, petrels and albatrosses, have made themselves masters of the sea in a higher sense than the most formidable pirate, for the latter is limited to the water, while the birds, not only by swimming and diving snatch the inhabitants of the waters from their own element, but they also capture those fish which, leaving the water for a moment to escape the Scylla of danger from other fishes, throw themselves into the air and into the power of a hungry and greedy Charybdis. And where is any fish in fresh water safe from the pursuit of birds?
No shell or other shelter affords adequate protection to the poor mollusks; but they, too, have to find their way through the maws of birds into the circulating stream of matter. It is true that they usually serve only as a temporary substitute for something else, and few of the inhabitants of the air live exclusively upon them; of these are those curious finches, so like the haw-finch, that live in the Galapagos Islands, descendants from South American castaways, which found no corn-grains on the rocks, but a nutritious though unaccustomed substitute in the shell-fish of the beach, whose shells their tough bills could crack with ease.
The hosts of birds consume immeasurable quantities of insects every day. In no place and no condition are creatures of this class secure from their pursuit. The fat larva, leading a tranquil existence in the depths of decaying wood, is the prey of the sagacious woodpecker. The portly spider, in her dark corner, does not escape the penetrating eye of the redstart. Little beetles and gnats, carried up into the air by ascending currents, are a welcome game to the high-flying swallows.
No more than animals can plants escape the demands of the birds' appetite. Of whatever plants can furnish, excepting only the wood, the birds take their tithes. Humming-birds, besides the nectar, devour the insects that go in after it. The Australian licmetis digs into orchid-roots and lily-bulbs with a bill admirably adapted to that use. The Polyborus chimango, of Chiloe, digs up freshly planted potatoes, to the ruin of the farmers, and eats them with relish. Some South American birds feed on aromatic leaves, and the New Zealand nightparrot prefers a delicate liverwort to all other food. But so slight is the nourishing power of this plant that the bird has to consume immense quantities of it, and his crop is swelled out after each meal enormously. Seeds, berries, and fruits furnish a most welcome sub-
