Mr. Audubon mentions finding three nests of this bird in Labrador, in each of which there were five eggs. These nests were placed on the top branches of the low firs peculiar to that country, composed of sticks, and slightly lined with moss and a few feathers. He describes the eggs as 1.75 inches long, and 1.25 broad, with a dull yellowish-brown ground-color, thickly clouded with irregular blotches of dark reddish-brown. One was found in the beginning of July, just ready to hatch. The young are at first covered with a yellowish down. The old birds are said to evince great concern respecting their eggs or young, remaining about them and manifesting all the tokens of anger and vexation of the most courageous species. A nest of this Hawk (S. I. 7,127) was taken at St. Stephen, N. B., by Mr. W. F. Hall; and another (S. I. 15,546) in the Wahsatch Mountains, by Mr. Ricksecker. The latter possibly belonged to the var. _richardsoni_. The nest of this bird found in Jamaica by Mr. March was constructed on a lofty tree, screened by thick foliage, and was a mere platform of sticks and grass, matted with soft materials, such as leaves and grasses. It contained four eggs, described as “round-oval or spherical” in shape, measuring “1.38 by 1.13 inches, of a dull clayish-white, marked with sepia and burnt umber, confluent dashes and splashes, irregularly distributed, principally about the middle and the larger end.” Four others, taken from a nest in the St. Johns Mountains, were oblong-oval, about the same size and nearly covered with chocolate and umber blotches. Mr. March thinks they belong to different species. Mr. Hutchins, in his notes on the birds of Hudson’s Bay, states that this species nests on rocks or in hollow trees; that the nest consists of sticks and grass, lined with feathers; and describes the eggs as white, thinly marked with red spots. In the oviduct of a Hawk which Dr. Richardson gives as _Falco æsalon_, were found “several full-sized white eggs, clouded at one end by a few bronze-colored spots.” A nest was found by Mr. Cheney at Grand Menan, from which he shot what he presumed to be the parent bird of this species. Its four eggs agreed with the descriptions given by Hutchins and Richardson much more nearly than with the eggs of this species. The eggs found by Mr. Cheney may have been very small eggs of _A. cooperi_, in which case the presence of the _columbarius_ on the nest cannot be so easily explained.