Mr. MacFarlane found this species not uncommon on the banks of Lockhart and Anderson Rivers, in the Arctic regions. In one instance he mentions finding a nest on a cliff thirty feet from the ground. There were four eggs lying on a ledge of the shale of which the cliff was composed. Both parents were present, and kept up a continued screaming, though at too great a distance for him to shoot either. He adds that this bird is by no means scarce on Lockhart River, and he was informed that it also nests along the ramparts and other steep banks of the Upper Anderson, though he has not been able to learn that it has been found north of Fort Anderson. In another instance the nest was on a ledge of clayey mud,—the eggs, in fact, lying on the bare ground, and nothing resembling a nest to be seen. A third nest was found on a ledge of crumbling shale, along the banks of the Anderson River, near the outlet of the Lockhart. This Hawk, he remarks, so far as he was able to observe, constructs no nest whatever. At least, on the Anderson River, where he found it tolerably abundant, it was found to invariably lay its eggs on a ledge of rock or shale, without making use of any accessory lining or protection, always availing itself of the most inaccessible ledges. He was of the opinion that they do not breed to the northward of the 68th parallel. They were also to be found nesting in occasional pairs along the lime and sandstone banks of the Mackenzie, where early in August, for several successive years, he noticed the young of the season fully fledged, though still attended by the parent birds. In subsequent notes, Mr. MacFarlane repeats his observations that this species constructs no nest, merely laying its eggs on a ledge of shale or other rock. Both parents were invariably seen about the spot. In some instances the eggs found were much larger than in others. Mr. Dall mentions shooting a pair near Nuk´koh, on the Yukon River, that had a nest on a dead spruce. The young, on the 1st of June, were nearly ready to fly. It was not a common species, but was found from Nulato to Sitka and Kodiak.