Naturally, these birds are inhabitants of caves and rocky cliffs, or of hollow trees; but, like the swifts, the moment a man builds a house or barn in Europe, or Asia, or South America, there certain swallows are sure to come to live with him, just as they do around our village and farm houses in North America. Hence the English people call their common species house-swallow, and we give the name barn-swallow to our similar one. This is the very common species with the long, deeply forked tail, which sets its nest of mud and straw on the beams of our barns or plasters it against the walls or roof, always _inside_ the building. Almost equally widespread and numerous is another barn-loving kind, distinguished by its short square tail and its habit of forming bulb-shaped nests wholly of mud, and of placing them in rows _outside_ the building, close up under the eaves. These last are better known as eaves-swallows. [Illustration: GAUDY TROPICAL BIRDS 1. Ara; Macaw. 2. Rose-Crested Cockatoo. 3. Senegal Parrot. 4. Mexican Toucan. 5. African Hornbill.] WELL-KNOWN MARTINS Martin is a name applied to various swallows, but with us it denotes the big purple one which in the warmer parts of the country gladly takes possession of the pretty bird-houses which many persons set on poles in their gardens. Another smaller, sooty-brown martin, is the sand-martin, or bank-swallow, which differs from all the rest in placing its eggs on a little bed of straw and feathers at the end of a long burrow which it bores into the face of a cliff of earth beside some river, where usually a large company live as happy neighbors. This species is one of the few birds known almost all over the world. CHAPTER XXIV PARROTS, PIGEONS, PEA-FOWL, PHEASANTS, ETC. The members of the parrot family are very interesting birds; in the first place because they are generally so gaily colored, in the second place because they are so easily tamed, and in the third place because many of them are such capital talkers. They nearly all spend the greater part of their lives in the trees, and if you look at their feet you will see that the first and fourth toes are turned backward while the second and third are directed forward. This gives the birds a great power of grasp, and helps them in climbing. At least five hundred different kinds of these birds have been discovered in different parts of the world, but we shall only be able to tell you about a few of them. Let us take first a parrot, then a parrakeet, then a cockatoo, then a macaw, and then a love-bird, as representing the various groups. THE GRAY PARROT