Dr. Coues mentions the taking of a single specimen of this bird in the Territory of Arizona in the winter, but no others were observed.
Audubon never met with this species south of North Carolina nor west of the Alleghanies. He regarded it as a sluggish bird, confining itself to the meadows and low grounds bordering the rivers and salt marshes, where its principal food appeared to be moles, mice, and other small quadrupeds. He has never known it to attack a duck on the wing, although it will occasionally pursue a wounded one. Except when alarmed, it flies low and sedately, and manifests none of the daring courage or vigor so conspicuous in most Hawks. They are also described as somewhat crepuscular in habit, watching for their food long after sunset, and Mr. Richardson speaks of their hunting for their prey “by the subdued daylight which illuminates even the midnight hours in the high parallels of latitude.” For these nocturnal hunts it is well fitted by the softness of its plumage, which renders its flight noiseless, like that of the more nocturnal birds.
These birds were once quite abundant in the low lands and marshes in the vicinity of Boston, but are now comparatively rare. They were abundant during October and November, and again in April. They usually kept on or near the ground, appeared to feed chiefly on small quadrupeds or reptiles, were never known to molest the poultry-yard, or even to destroy other birds.
Archibuteo sancti-johannis (black plumage).
They were very wary, and when approached with a gun would slowly and deliberately move off to a safer distance. Wilson found them quite abundant, during the winter months, in the meadows on the Delaware and Schuylkill Rivers, near Philadelphia, where they are still common. Though rendered very shy by the frequent attempts made to shoot them, they would never fly far at a time, usually from one tree to another, making a loud squealing noise as they arose. They all disappeared early in April.
He also speaks of them as common during winter in the lower parts of Maryland, as well as in the extensive meadows below Newark, N. J. He mentions having often seen this Hawk coursing over the surface of meadows long after sunset, and many times in pairs. They roost near these low grounds, and take their station at daybreak near a ditch, watching with patient vigilance for their prey.
Wilson, Audubon, and Nuttall appear to have known nothing in regard to the breeding of the Rough-legged Hawk. A pair was seen by Richardson at their nest, which was built of sticks, and on a lofty tree standing on a low moist alluvial point of land, in a bend of the Saskatchewan; but they were too wary to be shot, and he makes no mention of their eggs.
My nephews, H. R. and F. H. Storer, found a pair of Rough-legged Hawks nesting on a rocky cliff on the coast of Labrador, near the harbor of Bras d’Or. The nest was very rudely constructed of sticks, and placed on a high rock directly over the water, inaccessible from below, but readily approached from above. It contained three young birds and an egg. The young Hawks were just ready to fly, and all scrambled out as the nest was approached, and rolled the egg to the bottom of the cliff, but without injuring it. The nest contained four or five large rats peculiar to that region, collected by the old birds for their young. The old birds were in the light plumage. At the same time a young bird was taken alive from another nest by one of the sailors of their party, which was quite black even in its immature dress, and strikingly different from the young just mentioned.