The Great Night Heron of America, which is considered by Audubon and others as a distinct species, is seen as far as the northern and eastern extremities of the United States, but is unknown farther northwards. In the winter it goes as far as the tropics. These birds arrive in Pennsylvania in April, and immediately take possession of their old nurseries, usually in the depths of a cedar swamp, or of some inundated and inaccessible grove of oaks; there they pass the day till twilight comes, and then the parent birds sally forth to the sea-shores and marshes in search of food for themselves and young, proceeding in marshalled ranks, and uttering from time to time a guttural "kwah," in a hollow voice, that resembles the sound of a person vomiting. The eyries of the "Kwah" birds have been occupied from remote times by eighty or one hundred pairs, and when the trees are felled, they only remove to another part of the same swamp. * * * * * The BITTERNS (_Ardetta_) are recognisable by their comparatively small size, slender bill, low feathered tarsi, their short wings, in which the second quill is longer than the rest, and weak short tail. The plumage, which is by no means striking in its coloration, varies in hue according to the age and sex of the bird. THE LITTLE BITTERN. The LITTLE BITTERN (_Ardetta minuta_) is from fourteen to sixteen inches long, and from twenty-one to twenty-three broad; the wing measures five inches and three-quarters, and the tail two inches. This elegant bird is of a glossy blackish green on the crown, nape, back, and shoulders; the upper wing and under side are reddish yellow, spotted with black on the side of the breast; the quills and tail-feathers are black; the eye and bridles yellow. The pale yellow beak is brown at its culmen; and the foot greenish yellow. In the female all the dark parts are brownish black, and the light portions of the plumage pale yellow; the young have the crown and nape reddish brown, striped with a deeper shade, the under side spotted brown and reddish yellow, and lower belly and tail-covers white. The Little Bittern is only a summer visitor to Great Britain. It frequents marshes, osier holts, and other places in the neighbourhood of water, feeding on such small animal food as is there easily obtained. [Illustration: DAY AND NIGHT HERONS.] * * * * * [Illustration: THE COMMON BITTERN (_Botaurus stellaris_). ONE-FOURTH NATURAL SIZE.]