_Swallows._――The beautiful _Purple Martin_ is a great favorite of man in all parts of the country. The farmer prepares a little house for him, the Indian hollows a calabash, and as either mansion is to him indifferent, so is he equally acceptable to the husbandman and the hunter. Year after year he returns to the same mansion. In the middle states, the martins prepare their nest about the third week in April, and they rear two broods in the season. There are several other species, such as the _Barn_, _Cliff_, _White-bellied_, and _Chimney_. _Night-Hawks._――The _Whip-poor-will_ is a remarkable nocturnal bird migratory through nearly the extent of the states. It is well known for its sad and peculiar song. The _Chuck-will’s Widow_ is seldom found north of Virginia, and is particularly numerous in the vast forests of the Mississippi. Its note is strikingly different from that of the whip-poor-will. In sound and articulation it seems plainly to express the words which have been applied to it, pronouncing every syllable leisurely, and distinctly, putting the principal emphasis on the last word. In a still evening it may be heard at the distance of nearly a mile; the tones of its voice being strong and full. The flight of this bird is slow, skimming about the surface of the ground, frequently settling on old logs or on the fences, and from thence sweeping around in pursuit of various insects that fly in the night. Like the whip-poor-will, it prefers the declivities of glens, and other deeply shaded places, making the mountains resound with echoes the whole evening. _Pigeons._――The _Passenger Pigeon_ is the most remarkable American species. The head, throat, and upper parts of the body are ash colored; the sides of the neck are of a glossy variable purple; and there is a crimson mark round the eyes. These birds visit the different parts of North America in immense flocks. The most important facts connected with their habits relate to their extraordinary associations and migrations. No other species known to naturalists is more calculated to attract the attention of either the citizen or the stranger, as he has opportunity of viewing both of these characteristic habits while they are passing from north to south, east and west, and, _vice versa_, over and across the whole extent of the United States of America. These migrations are owing entirely to the dire necessity of providing food, and not merely to escape the severity of a northern latitude, or seek a southern one for the purpose of breeding. They consequently do not take place at any fixed period or season of the year. Indeed, it happens sometimes that a continuance of a sufficient supply of food in one district will keep these birds absent from another for years. Illustration: Passenger Pigeon.