Humming-birds are scattered over the greater part of South and North America, even as far north as Canada; but in Brazil and Guiana they are most abundant. At least 500 species are known. Among the more remarkable species we may note the Topaz-throated Trochilus, a native of Brazil; the Sickle-winged Humming-bird; the Double-crested Humming-bird; Gould’s Humming-bird; Cora Humming-bird; the Giant Humming-bird, which attains the size of a Swallow; the Dwarf Humming-bird, whose size does not exceed that of a bee; the Bar-tailed Humming-bird or Sapho Comet, a native of Eastern Peru; the Racket-tailed Humming-bird, so named from the shape of its tail, which spreads out at the extremity in the form of a racket; the Crested Humming-bird, with a double crest on the head of the male Bird; and the Sword-bill Humming-bird, with a bill as long as the whole body of the Bird. THE CROWS. [Illustration: CROWS AND RAVENS.] The Crows are divided into four groups or sub-genera—namely, the Crows properly so called, Pies, Jays and Nutcrackers. The genus Corvus, or Crow family, as limited by modern Naturalists, comprehends the Raven, the Carrion Crow, the Royston or Hooded Crow, the Rook, the Jackdaw, Great-billed Crow, Philippine Crow and Fish Crow. All these species have in many respects the same characteristics, and the same habits. With the exception of the Raven and Magpie, which live in pairs, the others reside together in companies, whether they are in quest of their daily food or roosting for the night. They are all possessed of intelligence, cunning, mischievous habits, the gift of imitation, though in different degrees, and the same provident habit of amassing provisions in secret places. This last peculiarity in the tamed Birds degenerates into a perfect mania, which leads them to carry off and hide everything that attracts or pleases their eye, especially gems and bright articles of metal. The whole group are easily tamed. The Crows, especially the Raven and the Carrion Crow, are omnivorous. Living or dead flesh, Insects, eggs, fruit, seeds—nothing comes amiss to their palate.