Captain Blakiston, having enjoyed unusual opportunities for observing the habits of the American Raven during his residence in high northern regions, characterizes the species as anything but solitary. During the day they are usually met with in pairs, except when drawn together in large numbers around the carcass of a dead animal. At night, during the winter, they repair to some chosen resting-place, usually a clump of trees on the edge of a prairie, and there roost in one immense body. One of these roosting-places was about a mile from Fort Carlton, and Captain Blakiston’s attention was first drawn to it by noticing that about sunset all the Ravens, from all quarters, were flying towards this point. Returning to the fort in the evening by that quarter, he found a clump of aspen-trees, none of them more than twenty-five feet high, filled with Ravens, who, at his approach, took wing and flew round and round. He also noted the wonderful regularity with which they repaired to their roosting-place in the evening and left it again in the morning, by pairs, on their day’s hunt. They always left in the morning, within a minute or two of the same time, earlier and earlier as the days grew longer, on cold or cloudy mornings a little later, usually just half an hour before sunrise. In April they all paired off, and their roosting-place became deserted. During an excursion about one hundred and fifty miles southwest of Fort Carlton, Captain Blakiston found several nests of Ravens with eggs, one of which was in a small tree near a lake, and was not more than fifteen feet above it. It contained six eggs, was about a foot in diameter, composed of sticks, and was lined with buffalo-hair and pieces of scarlet cloth, evidently picked up about an Indian camping-ground. Dr. Heermann states that while in California he always found the nests of the Raven placed high on bold precipitous cliffs, secure against danger; in the vast desolate plains of New Mexico he saw these birds building on low trees, and even on cactus-plants, less than three feet from the ground, showing how much circumstances and localities affect the habits of birds regarding incubation. A Raven, probably this species, is abundant on the plateau of Mexico. The Cerro Colorado, near Tehuacan, is the rendezvous of a large number of these birds, where, according to Sumichrast, at the time of the flowering of the _maguey_, they gather in great abundance, to feed on the blossoms of this plant, which are their favorite food.