Chapter I: GENUS NAUCLERUS. Vigors, Zool. Jour., II. p. 386. (1825.)

CHELIDOPTERYX. Kaup, Class., p. 112. (1844.)

Bill short and weak; wings and tail very long, the former pointed, the latter deeply forked. Tarsi very short; toes short. Contains not more than three species, two of which are American, and the other African.

1. Nauclerus furcatus. (Linn.) The Swallow-tailed Hawk.
Falco furcatus. Linn., Syst. Nat., I. p. 129. (1766.)

Cat. Car, pl. 4; Buff., Pl. Enl., 72; Wilson, Am. Orn., VI., pl. 51,
fig. 3; Aud., B. of Am., pl. 72, oct. ed. I. pl. 18; Gould, B. of
Eur., 1. pl. 30; De Kay, Nat. Hist. N. Y., Birds, pl. 7, fig. 15.

Wings and tail long, the latter deeply forked. Head and neck, inferior
wing-coverts, secondary quills at their bases, and entire under-parts,
white. Back, wings, and tail, black, with a metallic lustre, purple on
the back and lesser wing-coverts, green and blue on other parts. Tarsi
and feet greenish-blue; bill horn color.

Dimensions. _Female_—total length, 23 to 25 inches; wing, 16 to 17½;
tail, 14 inches. _Male_—rather smaller.

Hab. Southern States on the Atlantic, and centrally northward to
Wisconsin; Texas (Mr. Audubon); South Carolina (Prof. Gibbes);
Wisconsin (Dr. Hoy); Pennsylvania (Mr. A. F. Darley); Jamaica (Mr.
Gosse). Accidental in Europe. Spec. in Mus. Acad., Philada.

Obs. This very handsome Hawk is especially abundant in the Southern States. It cannot readily be confounded with any other North American species, though we have not been able to compare it with the _Elanoides yetapa_, Vieill., of South America, with which it is either identical or very similar.