Specimens of this bird are recorded in the government reports as obtained from the Yellowstone, from the Pecos River in Texas, and from Fort Fillmore in New Mexico. Mr. Dresser found it common throughout all of Texas in all seasons of the year, breeding in all parts, but preferring the heavily timbered country. He obtained its eggs from Systerdale and from the Medina River.
This Hawk is a strong and powerful bird, with a firm, steady, and protracted flight, frequently at a great elevation, and often moving quite a distance without any apparent motion of the wings. It is said to generally descend upon its prey from some fixed position, as the branch of a tree, and rarely to dart upon it when flying. It is a cautious bird, and rarely ventures near a house for poultry except when the dwelling is isolated and near its own haunts. It preys chiefly upon small quadrupeds, small birds, and reptiles. It usually darts upon a snake from the branch of a tree, and seizing it near the head bears it writhing through the air. In the valley of the Saskatchewan, Richardson states that it watches for the marmots, and when one imprudently ventures from its burrow, darts upon it, bears it a short distance off, and tears it to pieces.
As they fly, these birds utter a very peculiar and unpleasantly harsh cry or scream, which they repeat very frequently. Capt. Blakiston observed this at the Red River settlement, and speaks of it as the Squealing Hawk.
Though said to be thus generally cautious in exposing itself to danger in approaching a poultry-yard, it is not always thus cautious. Mr. Downes mentions an instance where one of these birds entered a garden in Halifax to pounce upon a tame Crow, and was captured alive by the owner.
Mr. Audubon states that after rearing their young they no longer remain mated, but separate and evince rather jealous hostility to each other than good-will. When one has taken any prey in sight of another, the latter will pursue and struggle with it for possession of the plunder. In these fights they scream vociferously while struggling for possession.
In the Southern States these Hawks begin to build in February; in the Middle States, from March the 24th to April 15th; and in New England usually from April to May. They construct a large nest, composed externally of coarse sticks and twigs, and lined with dried grasses, moss, and leaves, built for the most part in the fork of a lofty tree. The eggs are usually four in number.
Mr. Augustus Fowler of Danvers, who is familiar with the habits of this bird, writes me that in Massachusetts they usually begin to build their nests about the first of April, selecting some tall tree near the middle of the woods, the branches of which form a crotch near its trunk. To this chosen spot the female carries a sufficient quantity of sticks for its outside (the male taking no very active part in the matter), and for its inside she uses the bark from the dead branches of the chestnut, which she beats and pecks to pieces with her bill, making it soft and pliable, or gathers the fallen leaves of the pine, or some other soft material, which she finds conveniently, as a lining, which is about one inch in thickness. It is thirteen inches in diameter from outside to outside, and seven inches in diameter on the inside, while its depth is two and a half inches. The female usually lays five eggs, which are spherical, of a dirty-white color, and marked with large blotches of brown; on some they cover almost the whole egg, while others are marked mostly on the large end, and some even of the same nest are so faintly marked as to appear almost wholly white. They are 2.12 inches in length and 1.95 in diameter.
In Jamaica, according to Mr. March, these Hawks do not confine themselves to any particular mode or place for breeding, height seeming to be their chief object. He has found their nest in a quite accessible tree, not more than twenty feet from the ground, and near a frequented path. In another instance a pair nested for several years on the roof of the turret of the belfry of the Spanishtown Cathedral church. The nest he describes as a platform of dry sticks, more than a foot across and two or three inches thick. The bed of the nest is about six inches across and two deep, of fine inner bark, grass, and leaves, containing four or five eggs, nearly spherical, measuring 2.25 by 2.75 inches, of a dirty or clayish white, dashed with blotches and spots of vandyke-brown and umber, often running with a light shade into the ground-color.
The eggs of the Red-tail exhibit great variations in nearly every respect except their shape, which is pretty uniformly a spheroidal-oval. Their ground-color varies from white to a dingy rusty drab, their markings vary greatly in colors, shades, size, frequency, and distribution. In some the markings are small, few, and light, and the egg appears to be of an almost homogeneous brownish-white. In others the ground is completely concealed by large and confluent blotches of deep and dark purplish-brown, burnt umber, and a peculiar shade known as Dutch umber. In some the markings are distributed in fine and frequent granulations, diffused over the entire surface of the egg, producing the effect of a color of uniform umber brown, through which the ground of yellowish-white can only be traced by a magnifying-glass. Four eggs in my cabinet average 2.22 inches in length by 1.72 in breadth. The largest egg measures 2.55 by 1.90 inches; the smallest, 2.10 by 1.70. The capacity of the largest to the smallest is nearly as five to four.
The season in which this Hawk deposits its eggs varies considerably. Mr. Jackson of West Chester, Penn., gives March 24 the earliest, and April 15 the latest, in which he has met with its fresh eggs.