LOCALITY
The nest is placed in a tree in a small grove, or in a woods, frequently, near a pond or stream.

POSITION
It is built either in a prependicular [perpendicular] or horizontal fork, generally in the latter position near the extremity of a limb fifty feet or more from the ground. Nests are sometimes found much lower, but as a rule they are high up in the trees.

MATERIALS:
The materials of construction consist principally of coarse sticks, to which grasses, feathers, corn-silk, and similar materials. may be added for the lining. The nest is a rough affair, measuring from a foot and a half to two feet in diameter and but a few inches in thickness. It has been compared to the nest of the Crow; but it is by no means so elaborately constructed. Its concavity is very slight, and frequently but sparingly lined.

EGGS:
The eggs of a set vary in number from three to six, four being the usual complement. The shell is somewhat granular, and varies in color from chalky white to a faint greenish-blue. Ordinarily it is tinted with greenish-blue. Sometimes the tint is of different intensity in different parts of the same egg. The markings consist of blotches, spots, and, occasionally, streaks of brown. Usually the marks are very indistinct, and may easily be overlooked. Sometimes the brown is decided. The markings are most abundant about the base. Some eggs are entirely unmarked. In size the eggs average about 1.48 x 1.90. According to Dr. Brewer, eggs of this species vary from 1.50 to 1.60 in short-diameter, and from 1.85 to 2.00 inches in long-diameter. Dr. Coues, in "Birds of the North-West," gives the variations from 1.80 to 2.10 in long-diameter, and from 1.55 to 1.60 in short-diameter. A set of eggs collected by Mr. Chas. Dury of Cincinnati, measures respectively 1.45 x 1.90, 1.46 x 1.87, and 1.46 x 1.88. Incubation is said to last twenty-seven days.

DIFFERENTIAL POINTS:
See Circus hudsonius, Marsh Hawk.
[When you look at Circus hudonius- Marsh Hawk you find, “See Broad-winged Hawk, page 214.”

DIFFERENTIAL POINTS for the BUTEO PENNSYLVANICUS-Broad-Winged Hawk: The nests of all the large hawks which build in trees and very similar. They are so difficult to obtain in perfect condition and so large, that but little interest is attached to them other than their location, position, and in a general way the materials of their construction. The following species of hawks breed in Ohio: Red-tailed Hawk, Fish Hawk, Red-shouldered Hawk, Broad-winged Hawk, Coopers Hawk, Marsh Hawk, Sharp-shinned Hawk, and Sparrow Hawk. The eggs of these eight hawks vary in size in the order names. The most highly-colored eggs of the lot are the Fish Hawk’s. The Red-tailed hawk’s are the largest, but the Fish Hawk’s approach them very closely in size. The third in size, and quite similar to the Red-tailed Hawk’s in markings are the eggs of the Red-shouldered Hawk. The chief point of difference is that of size, this is usually sufficient to differentiate them. The next in size is those of the Broad-winged Hawk, they are about as much smaller than the Red-shouldered Hawk’s as the Red-shouldered Hawk’s are smaller than the Red-tailed Hawk’s. This difference together with the difference in color of the markings will usually enable one to distinguish them. Except the eggs of the Fish Hawk, those of the Sharp-shinned Hawk and Sparrow Hawk are the most heavily marked. Their size is much less than any of the others. See “Differential Points” under “ACCIPITER FUSCUS-Sharp-shinned Hawk.” The faintest marked eggs are those of the Cooper’s Hawk and the Marsh Hawk. The latter are a little the smaller and ground-color is a little fainter, but they are so nearly alike that any but typical specimens can not be positively identified by size, color, and markings alone.]

[DIFFERENTIAL POINTS: ACCIPITER FUSCUS-Sharp-shinned Hawk:
The eggs of the Sharp-shinned Hawk are so characteristic in their markings that this feature, when taken with their size, is sufficient to identify them. The eggs of the Sparrow Hawk may be the exact dimensions expected in the eggs of the species being considered, but their markings are so essentially different in color that they can never be mistaken, the one for the other. See page 214.]
]

REMARKS:
Fig, 2, PLATE XLIX, represents the usual sizes, shapes, and colors of the eggs of the Cooper's Hawk. Two of the eggs figured were collected by Mr. Chas. Dury, April 29th, 1879, near Cincinnati; the other egg figured, came from a set collected in Ross County, in May, 1880.

My experience in collecting the eggs of this species has been very limited. I have found numbers of nests, but never an accessible one that contained fresh eggs. I raised from a nestling a male Cooper's Hawk, and kept him until he was nearly a year old. He was an interesting pet, full of cunning and boldness. He became so tame that he had the liberty of the town. He would wander about from tree to house-top, and would sometimes be gone a whole day. He was very fond of buggy-riding, and would sit on the dash-board for hours manifesting the greatest interest in the objects passed. I intended to teach him to hunt, and was making rapid progress with his lessons, when I was obliged to leave for college. Some months later a letter brought me news of his death. A boy had killed him with a stone. The Cooper's Hawk, or the Hen Hawk, as the species is called by the country people, is the most destructive to poultry of any of the family. It is active on the wing, and of courageous spirit, and does not hesitate to attack birds much larger than itself. It catches many small birds upon the wing, and it sometimes even attacks ducks. I have twice seen a Cooper's Hawk dart into a flock of Red-winged Blackbirds, and in each instance it secured a Blackbird in its talons.
Instead of Buteo cooperi, PLATE XLIX, read Accipiter cooperi.