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Show 224 AVES. p1 u mage, 1·m permeable to water, all • concur with the feet in making good navigators of the Palmipedes. . In other birds, which most commonly are partially web-fio ote d , a t least between the external to.e s, we observe elevated 1 .. tarsi· •, 1e gs divested of feathers at thetr owe·r ·e xtre~m itieds;i a I ong, thm. shape ' and in fine, all the. reqUISites 10r W. a ng along the shores of rivers to seek their food. Such, m fact, is the regimen of the greater number; and although ~orne of them inhabit dry grounds, they are called, Shore-Bzrds, or Waders. Among the true land birds, the Gallinacere, like our domes· tic Cock, have a heavy carriage, a mod.erate beak, the upper mandible of which is arched; the nostnls partly covered by a soft and inflated scale ; the toes almost always indented on ~he edges, and short membranes between the bas~s of the ant~nor ones. They :fly heavily, and but a short distance at a time. Their chief food is grain. Birds of prey have a hooked beak, the point of which is sharp, and curved downwards ; the nostrils pierced in a mem· brane which invests the whole base of that beak, and feet armed with vigorous talons. They live on :flesh, pursue other birds, and are consequently, for the most part, vigorous in :flight. The greater number have still a slight web between the external toes. The Passe1·inre comprise many more species than all the other families ; but their organization presents so many analo· gies that they cannot be separated, although varying greatly in size and strength. Their two external toes are united at the base, and sometimes for a part of their length. Finally, the name of Scansorire, or Climbers, has bee.n given to those birds whose external toe, like the thumb, 18 directed backwards, because the greater number profit, ~y a conformation so favourable to a vertical position, to chmh trees.(l) (1) From my first Tableau Elementaire, in 1798, I was obliged to sup~ress th~ Linna:an order of the Pica:, which bas no one determined character. Iihger an the greater number oflate naturalists have assented to this suppression. AVES. 225 Each of these orders is subdivided into families and genera, and principally from the conformation of the beak. But these different groups frequently pass into each other by almost imperceptible gradations, so that there is no other class in which the genera and sub-genera are so difficult to limit. ORDER I. ACCIPITRES, Lin. Birds of prey are known by their hooked beak and talons, powerful weapons, with /which they pursue other birds, and even the weaker quadrupeds and reptiles. They are among Birds what the Carnivora are among Quadrupeds. The muscles of their thighs and legs indicate the strength of their claws; their tarsi are rarely elongated; they have, all, four toes; the nail of the thumb and that of the internal toe are the strongest. They form two families, the diurnal and the nocturnal. The eyes of the diurnal Birds of prey are directed sideways; they have a membrane called the cera, covering the base of the beak, in which the nostrils are pierced ; three toes before, one behind, without feathers, the two external ones almost always united at base by a short ;membrane; the plumage dense, the quills strong, and great power on the wing. Their stomach is nearly altogether membranous, their intestines of · hut small extent, their crecum very short, their sternum broad and completely ossified in order to give more extended attach~ ents to the muscles of the wings, and their fourchette semiCircular and widely separated, the better to resist the violent flexions of the humerus necessary to a rapid flight. ' Linn:eus comprehended them all under two genera, which are so many natural divisions, the Vultures and the Falcons. Vot. I.-2 D |
