In this section of the Insessores the beak is strong and on the whole conical, broad at the base and tapering with considerable rapidity to the apex (fig. 345, D). The upper mandible is not markedly toothed at its lower margin. Good examples of the conirostral type of beak are to be found in the common Sparrow, Hawfinch, or Bullfinch. The greater number of the Conirostres are omnivorous; the remainder are granivorous, or feed on seeds and grains. The sub-order includes the families of the Horn-bills (Bucerotidae), the Starlings (Sturnidae), the Crows (Corvidae), the Cross-bills (Loxiadae), and the Finches and Larks (Fringillidae).
In the Horn-bills the conirostral shape of the beak is masked, partly by its being of very great size, and partly by the fact that above the upper mandible is placed a hollow appendage like a kind of helmet. Both the beak and the appendage above it are rendered light by the presence of numerous air-cells. The Horn-bills are exclusively confined to the warm countries of the eastern hemisphere, and are the largest of all the Insesso-rial birds, sometimes attaining the size of a goose; and they must be regarded as only provisionally placed in this order. They live on fruits, and make their nests in the holes of trees. The best-known species is the Rhinoceros Bird (Buceros rhinoceros) of India and the Indian Archipelago.
The family of the Corvidae, or Crows, is an extremely extensive one, and includes a large number of very dissimilar-looking birds, all characterised by their long, strong, and compressed beaks, the tip of the upper mandible being slightly hooked and more or less notched. In this family are the Jays (Garrulinae); the true Crows or Corvinae (comprising the Rooks, Carrion-crows, Ravens, Jackdaws, Magpie, Chough, &c), and the Birds of Paradise (Paradiseidae). These last differ considerably from the ordinary Corvidae, but can hardly be separated as a distinct family. They are amongst the most beautiful of all birds, and are entirely confined to New Guinea and the neighbouring islands. They feed upon insects and fruit, and are largely destroyed for the sake of their feathers, The natives who capture them usually cut off their legs; hence the notion formerly prevailed that the Birds of Paradise were destitute of these limbs. It is only the males which possess the brilliant plumage, the females being soberly dressed; and in accordance with this fact, it is stated that the Birds of Paradise are polygamous, being in this respect an exception to almost the entire order of the Insessores* "They are characterised by extraordinary developments of plumage, which are unequalled in any other family of birds. In several species large tufts of delicate, bright-coloured feathers spring from each side of the body, forming trains, fans, or shields; and the middle feathers of the train are often elongated into wires, twisted into fantastic shapes, or adorned with the most brilliant metallic tints. In another set of species, the accessory plumes spring from the head, the back, or the shoulders; whilst the intensity of colour and of metallic lustre displayed by their plumage, is not to be equalled by any other birds, except, perhaps, the Humming-birds, and is not surpassed by these." (Wallace.)
The family of the Starlings (Sturnidae) is not separated from that of the Crows by any important characters. Besides our common Starlings, it includes a number of other more or less singular birds, of which the Bower-birds of Australia are perhaps the most peculiar. These curious birds have the habit of building very elaborate bowers, often very beautifully constructed and of considerable size, in which they amuse themselves and apparently make love to one another. These bowers are wholly independent of their nests, which they construct elsewhere.
The last family of the Conirostres is that of the Fringillidae, comprising the Finches, Linnets, and Larks. In these birds the bill is stout and conical, with a sharp apex, but not having the upper mandible toothed. The toes are adapted for perching, and are provided with long and curved claws, that of the hinder toe being usually longer than the rest. They are almost all monogamous, and they build more or less elaborate nests. In this family are the true Finches (Fringilla), the Sparrows, (Pyrgita), the Linnets and Goldfinches (Carduelis), the Whydah Finches (Vidua), the Grosbeaks (Coccothraustes), the Bullfinches (Pyrrhula), and many others, but their numbers are so great that any further notice of them is impossible here. It may be mentioned, however, that the Finches of the Old World are represented in the tropical parts of America by the Tanagers (Tana-gridae), remarkable for their brilliant colours.
* The Humming-birds are thought to be polygamous, and this is certainly the case with the Whydah Finch (Vidua).
The only remaining members of the Conirostres which require notice are the Crossbills (Loxiadae), which are sometimes placed with the Finches, and sometimes considered as a separate family. In these birds the structure of the beak is so peculiar that its conirostral character is completely masked, and it has been looked upon as a deformity. Both mandibles, namely, cross one another towards the tip, giving the entire bill a most remarkable appearance. In point of fact, however, instead of being a deformity, the bill of the Cross-bills is a beautiful natural adaptation, enabling the bird with the greatest facility to tear in pieces the hard fir-cones, on the seeds of which it feeds.