Dr. Suckley found them abundant about Fort Steilacoom early in August. Near Puget Sound this species is thought to breed in the recesses of the Cascade Mountains, only coming down upon the open plains late in the summer. Dr. Newberry found it paired and nesting about the Klamath Lakes, and states that it also occupies all the region south of the Columbia, in Oregon. Mr. Dresser states that he found this Falcon common about Bexar and the adjoining counties during the entire year, and that they occasionally breed near the Medina River. I have been unable to find any satisfactory evidence that this Hawk ever breeds in any part of Massachusetts, or anywhere south of the 44th parallel in the Eastern States, except, perhaps, in mountainous regions. This Hawk is remarkable for its rapid flight, and its courage and its enterprise in attacking birds as large as or even larger than itself, though generally it only preys upon smaller birds, such as Grakles, Red-winged Blackbirds, Robins, and Pigeons. Dr. Cooper states that having been attracted by an unusual screaming of some bird close to the house, he was surprised to find that one of these Hawks had just seized upon a Flicker, a bird as large as itself, the weight of which had brought it to the ground, and which it continued to hold in its claws even after it had been mortally wounded. Dr. Heermann once found one of these birds just preparing to feed on a large and plump California Partridge. In Tamaulipas, Mexico, where Lieutenant Couch found it quite common, he speaks of it as being very quiet, flying but little, and generally watching for its quarry from the limb of a dry tree. Mr. Audubon makes no mention of any peculiarities of habits. Mr. Nuttall was evidently unfamiliar with it, stating it to be unknown in New England, and a resident of the Southern States only. In Nova Scotia, Mr. Downes speaks of it as common, breeding in all the wooded parts of the country. It is said to be not troublesome to the farmer, but to feed upon the smaller birds. He mentions that once, on his voyage to Boston, one of these birds flew aboard and allowed itself to be captured, and was kept alive and fed readily, but soon after escaped. Mr. B. R. Ross, in his notes on the birds and nests obtained by him in the country about Fort Resolution, Lapierre House, and Good Hope, mentions this bird as the most common of the true Falcons in that district, where it ranges to the Arctic coast. Its nest is said to be composed of sticks, grass, and moss, and to be built generally in a thick tree, at no great elevation. The eggs, he adds, are from five to seven in number, 1.60 inches in length by 1.20 in breadth. Their ground-color he describes as a light reddish-buff, clouded with deep chocolate and reddish-brown blotches, more thickly spread at the larger end of the egg, where the under tint is almost entirely concealed by them. This description is given from three eggs procured with their parent at Fort Resolution.