The DOUBLE-TOOTHED HAWK (_Harpagus bidentatus_) resembles the Falcons
in its general form, but is recognisable by its comparatively small
head, long broad tail, and short wings. The beak is very peculiar in its
construction, the upper portion being excised immediately behind the hook
at its tip, and the lower mandible, which terminates abruptly, has near
its extremity two sharp teeth at each side; the third quill of the wings
is longer than the rest, the tarsi are short, and of the same length as
the toes. This bird, of which there are two species, is only found in
South America.
The _Guaviao_, as the Double-toothed Hawk is called by the Brazilians,
is thirteen and a half inches long and twenty-six inches broad; the wing
measures eight inches, and the tail six inches. The plumage upon the
upper part of the body is blackish grey, embellished with a metallic
lustre; the under portions are reddish brown, with narrow white stripes
upon the throat; the rump is also white, the quills of the wings are
brown, ornamented with an irregular border, which is pure white upon the
inner web; the tail is black above, brown beneath, and marked with three
broad and crooked lines; the eye is light carmine, the cere greenish
yellow, the beak blackish grey, and the feet of a beautiful reddish
yellow. The plumage of the young is brown above and white beneath,
delicately marked with undulating brown lines of various shades.