341. Buteo albicaudatus sennetti. 22 in.
Adults grayish-slate above and to the sides of the throat; tail and underparts white, the former with a subterminal band of black and indistinct wavy lines and the latter with fine barring on the sides. The shoulders are largely chestnut. Young birds are brownish-black above and usually white below, but the underparts are variable—often streaked with rusty and blackish, or even wholly black.
They are useful hawks, their food consisting chiefly of insects and moles or mice.
Nest.—Built in bushes in open land, rarely more than six feet above ground. Composed of sticks, dry weeds and grasses making a bulky structure visible for a long distance. Three eggs are not uncommon but two is the usual number; they are dirty white with very few marks of brown (2.35 × 1.85). Their nesting season ranges from as early as February to July.
Range.—Not uncommon on the Gulf coast of Texas and in the lower Rio Grande Valley, southwards into South America.
SWAINSON HAWK
342. Buteo swainsoni. 20 in.
This species has the greatest variety of plumages of any of our hawks. It has only three outer primaries notched near the tips, while the two last species, which are the only ones that can be confused with it, have four. Adults in the light phase have a band of rich chestnut across the breast. Adults in the dark phase are uniform blackish-brown, with some rusty edgings and with thighs more or less rusty. Young birds are buffy below, with elongated blackish spots. Its harmless character can be understood from the fact that it is no unusual sight to find other birds, such as Arkansas Kingbird and Bullock Oriole, nesting in the same tree; and the first mentioned species goes even further than this, sometimes constructing its home in the sides of the nests of the hawks.
Nest.—Of sticks and twigs, either in trees or on the ground on rocky ledges; eggs white, spotted with brown (2.20 × 1.70).