Scratching birds. Feet with strong, obtuse, scratching claws; mandible vaulted; nostrils pierced at the base, covered by a cartilaginous scale. I. _Gallinaceæ_ (Polygamous), Pea-fowl, Partridge, Pheasant, Quail, Grouse, Pentados, Turkey, Curassow. II. _Columbaceæ_ (Monogamous), Pigeons, Gouravinago. IV. CANTORES. Singing birds. Legs short and slender, three toes before and one behind. In this order, according to Professor Owen, the brain attains its greatest proportionate size, and the organs of the voice their greatest complexity. I. _Dentirostres_, Shrikes, Wrens, Wagtails, Thrushes, Warblers, Manakins. II. _Conirostres_, Birds of Paradise, Crows, Tits, Starlings, Buntings, Larks, Finches, Grosbeaks. III. _Tenuirostres_, Nuthatch, Creeper, Sunboard. IV. _Fissirostres_, Swallows, Martins. V. VOLITORES. Birds moving solely by flight. Skeleton light and buoyant; head large; keel deep (entire on the Humming-bird); wings powerful, in some long and pointed; legs small and weak. The order includes-- I. _Cypselidæ_, Swifts. II. _Trochilidæ_, Humming-birds. III. _Caprimulgidæ_, Night-jar. IV. _Trogonidæ_, Trogons. V. _Prionitidæ_, Momots or Motmots. VI. _Meropidæ_, Bee-eaters. VII. _Galbulidæ_, Jacmar. VIII. _Coraciadæ_, Rollers. IX. _Capitonidæ_, Puff-bird. X. _Alcedinidæ_, King-fishers. XI. _Bucerotidæ_, Hornbills. VI. SCANSORES. Climbing birds, with opposing toes in pairs, two behind and two before. The order includes-- I. _Ramphastidæ_, Toucans. II. _Bucconidæ_, Barbets. III. _Cuculidæ_, Cuckoos. IV. _Picidæ_, Woodpeckers. V. _Musophagidæ_, Plantain-eaters. VI. _Coliidæ_, Colys. VII. _Psittacidæ_, Parrots. VII. RAPTORES. Rapacious birds, with strong, curved, pointed, and sharp-edged beak; legs short and robust, three toes before and one behind, armed with strong, crooked talons. The order includes-- I. _Nocturnes_, Owls. II. _Diurnes_, Eagles, Vultures, Hawks. CHAPTER I. THE NATATORES, OR SWIMMING BIRDS. The Natatores are obviously devoted, by their organisation, to an aquatic life. Their constant haunts are found on the great rivers and lakes, or on the coast. They are chiefly characterised by the form of their feet. The toes are united by marginal membranes in the Coots and Water-rails, or in others by the extension of webs between and uniting the toes, of a soft membrane slightly lobed; hence the name of _Palmipedes_, or web-footed, usually applied to them. These broad palmate feet, acting at the end of a long lever, strike the water with great force when fully expanded, being favoured by their backward position. When the bird recovers its stroke, the toes are relaxed in their forward movement, preparatory to another effort; thus progression through the water is obtained.