In a specimen from the Platte (5,577, ♂; W. S. Wood) white prevails on the tibiæ, the bars being dark ferruginous upon a white ground; the flanks are similarly marked, the other lower parts, however, immaculate; there is much concealed white on the scapulars. The rufous tinge of the tail is very deep, while there is a transverse series of black blotches, indicating the course of a transverse band near the end.
Habits. The California Squirrel Hawk appears to be an exclusively western species, occurring as far to the east as Nebraska and Kansas, and as far to the north as the Plains of the Saskatchewan and Washington Territory. It occurs as far to the southeast as Texas, and has been found also in New Mexico and in Arizona.
This species was first noticed and described in a paper on the natural history of California published in the Transactions of the Royal Academy of Berlin, in 1838, by Professor Lichtenstein, a Prussian naturalist. It was first brought to the notice of American naturalists by Mr. Edward M. Kern, of Philadelphia, who accompanied Colonel Fremont in his expedition of 1846, and who brought home specimens.
Dr. Coues found it quite abundant about Fort Whipple, where it was especially numerous in the winter, and where also he thinks it probable that it is a permanent resident. He found it more generally frequenting meadows, plains, and the more open woods. He usually found their stomachs filled with arvicolæ and other small quadrupeds peculiar to that country. It could always be readily recognized by its conspicuously white under parts, contrasted with its dark chesnut tibiæ and reddish back.
Archibuteo ferrugineus.
At San Pedro, on the southern coast of California, he again found this Hawk very common. It there alights very freely on the ground, where he often observed it. At Fort Whipple he only saw it on trees. At San Pedro its choosing thus the bare plain may have been a matter of necessity.
Dr. Kennerly observed a single individual of this species in a “prairie-dog-town” of large extent, near Fort Davis. It was intently watching at the hole of one of these animals. While in this position, it was observed to strike at the prairie-dog with its claw, when one of these animals protruded its head. As it was very intently watching its prey, it was easily approached and shot.
Dr. Heermann observed this Hawk in the valley of the Sacramento, where he thought it rather rare, but afterwards, during his connection with the government surveying party under Lieutenant Williamson, in the southern part of the State, he found it very abundant. On one occasion five or six individuals were in view at the same moment, among the mountains, sixty miles east of San Diego. It was there much more abundant than any other species. As large tracts of that country frequented by these birds are entirely without trees, they alight on the ground or on some slightly elevated tuft of grass, or a stone, where they sit patiently for hours watching for their prey, which was always found to consist of mice and other small quadrupeds. In one instance the crop was found filled with the remains of a ground squirrel.
Dr. Heermann states that he found the nest and eggs of this bird on the Consumnes River. The nest was in the fork of an oak, and was composed of coarse twigs and lined with grasses; the eggs were two in number, white with faint brown dashes. The nest was placed in the centre of a large bunch of mistletoe, and would have escaped notice had not the Hawk, in flying, betrayed her retreat.