BY PROFESSOR FROST. [Illustration: THE QUA BIRD. (_Ardea Nycticorax._ WILSON.)] THIS bird, otherwise known as the Night Heron, and the Rail, is found both in Europe and America. Its habits are somewhat different on the two continents, but the American bird may be safely considered as the type of the species. It is called Qua Bird on account of the rough guttural sound, _qua, qua_, which it utters while seeking its prey; and by some, Night Heron, from the circumstance of seeking its prey at night. During the day the Qua Birds perch in silence on high trees, and it seems probable that their eye cannot sustain the rays of the sun. But at night few birds are more active or enterprising. They are generally found in flocks, in the vicinity of deep swamps, or marshy woods, partially submerged by water. From these places troops of Qua Birds issue at twilight, and scatter themselves along ditches and by the river shore, to search for food. “On entering the swamp,” says Wilson, “in the neighborhood of one of these breeding places, the noise of the old and the young would almost induce one to suppose that two or three hundred Indians were choking or throttling each other. The instant an intruder is discovered, the whole rise in the air in silence, and remove to the tops of the trees in another part of the woods, while parties of from eight to ten make occasional circuits over the spot, to see what is going on. When the young are able they climb to the highest part of the trees, but, knowing their inability, do not attempt to fly. Though it is probable that these nocturnal birds do not see well during the day, yet their faculty of hearing must be exquisite, as it is almost impossible, with all the precautions one can use, to penetrate near their residence without being discovered. Several species of hawks hover around, making an occasional sweep among the young; and the Bald-Eagle himself has been seen reconnoitering near the spot, probably with the same design.”