To another order—the order Macrochires—belong those most beautiful of all birds, the humming birds, found only in America, and long thought to be allied with the really very different sun birds just mentioned. With these may be associated the swifts (which have such marvellous powers of flight) and the wide-gaped goat-suckers or nightjars.
Woodpeckers are considered to form an order (Pici) by themselves, while the cuckoos are thought to be near relations of the beautiful and eccentric toncans, the plaintain-eaters, the touracous, the kingfishers, the hoopoes, the bee-eaters, the hornbills, and the trogons, all, from the cuckoos to the trogons, being included in the order Coccyges.
The parrots form an isolated group of birds—the order Psittaci. Their most peculiar forms are the macaws on the one hand, and the brush-tailed loris on the other. The order Accipitres includes all the birds of prey—that is to say, the eagles, falcons, hawks, buzzards, vultures, and owls. In this order is included the long-legged secretary bird, which looks like a cross between a hawk and heron.
Pelicans, gannets, cormorants (or shags), and darters go together to constitute the order called Steganopodes. The flamingoes are isolated, and by themselves form the order Odontoglossæ. The same is the case with the penguins, which have the order Impennes assigned exclusively to them.
The ducks and geese form alone the order Lamellirostres, in which is included the curious bird Palamedea, which is a goose adapted to live in trees in harmony with its South American forest habitat.
The rails and coots go with the bustards and cranes to constitute the order Alectorides. Similarly the auks, divers, puffins, terns, and grebes, noddies, and guillemots may be associated together in one order—the order Pygopodes. The gulls and petrels form another association—the order Gaviæ; while the plovers, snipes, curlews, peewits, turnstones, &c., constitute the order Limicolæ. The order Heridiones includes the herons, the bitterns, the storks, spoonbill, ibis, &c.
All the foregoing birds have a multitude of points in common; indeed, so close is the similarity of their structure that their subdivision into orders is a matter of much difficulty and dispute. They are collectively spoken of as the Carinatæ, from the keeled form of their breast-bone.
Widely apart from them stands another group made up almost entirely of large birds, which agree not only in having no power of flight, but also in certain significant structural characters, amongst which may be mentioned the absence of a keel on the breast-bone.
This latter group is sometimes spoken of as the order Struthiones from the ostrich (Struthio), which is its typical form. Sometimes these keelless birds are called Ratitæ. Besides the ostrich, the rhea, cassowary, and emeu are included within the group; also the small and nocturnal Apteryx of New Zealand and those giants of featherdom, the huge species of dinornis, all also of New Zealand and all now extinct.
With this our list of birds might close, but for a bird which anciently existed in Europe so strangely different from all modern kinds, that it must certainly be here adverted to. This bird is the Archeopteryx, found in fossil in the Solenhofen States.