38 
U. S. P. R. R. EXP. AND SURVEYS-ZOOLOGY-GENERAL REPORT. 
Only inhabits the southern States of North America, and probably Mexico and Central 
America. In the southern division of this continent this bird is represented by another species 
with which it has been confounded. 
ROSTRHAMUS, Lesson. 
Rostrhamus, Lesson, Traite d’Orn. I, p. 55, (1831.) 
Bill long, very slender, hooked and sharp at the tip; wings long, pointed ; tail rather long, emarginated ; tarsi and toes 
rather long ; claws very long, slender, acute. The present is the only species. 
ROSTRHAMUS SOCIABILIS, Vieillot. 
Herpelethercs sociabilis, Vieill. Nouv. Diet. XVIII, 318, (1817.) 
Cymindis Itucopygius, Spix, Av. Bras. I, p. 7, (1824.) 
Roslrliamus niger, Lesson, Traite, I, 56, 11831.) 
Falco hamatus, Illiger. 
Figures. —Temm. PI. Col. 61, 231; Spix. Av. Bras. 1, pi. 2. 
Adult. —Tail at base and under tail coverts white, all other parts black. Naked space before the eye yellow ; bill and claws 
black ; feet yellow. Quills and tail black, the latter narrowly tipped with ashy white. 
Younger —Throat and line over and behind the eye dull yellowish white ; all other parts brownish black, mixed with dull 
yellowish white on the under parts. 
Young .—Pront stripe behind the eye and throat dull reddish white ; upper parts brown ; many feathers edged with pale 
ferruginous ; under parts yellowish, with longitudinal stripes of black ; tail at the tip and at base and under tail coverts dull 
yellowish white ; tarsi yellowish green. 
Total length, female, about 16 inches ; wing, 14 inches ; tail, 7k inches. Male rather smaller. 
Hab. —Florida, (Mr. Edward Harris, Dr. Heermann.) Spec, in Mus. Acad., Philada. 
This is a well known South American bird, first ascertained to inhabit Florida by Mr. 
Edward Harris, and subsequently by Dr. Heermann and Mr. Ivrider. It is remarkable for its 
very slender and hooked bill, unlike that of any other falcon, and can very easily be identified 
by that character. 
This bird undoubtedly breeds in Florida, as young specimens were obtained by Mr. Harris. 
It has not been ascertained to inhabit any other part of the United States. 
CIRCUS, Lacepede. 
Circus, Lacepede, Mem. d’Inst. Paris, III, CXI, 506, (1803.) 
Face partially encircled by a ring or ruff of short projecting feathers, as in the owls. Head rather large ; bill short, com¬ 
pressed, curved from the base ; nostrils largo ; wings long, pointed ; tail rather long, wide ; tarsi long and slender ; toes mod¬ 
erate ; claws rather slender and weak. 
This genus embraces about fifteen species, inhabiting all parts of the world, some of which 
much resemble each other. One species only is known to inhabit North America. 
CIRCUS HUDSONIUS, L inn mus . 
Tlie Harrier—The Marsh Hawk. 
Falco hudsonius, Linn. Syst. Nat. I, 128, (1766.) 
Falco uliginosus, Gm. Syst. Nat. I, 278, (1788.) 
Falco uropogistus, Daudin, Traite d’Orn. II, 110, (1800.) 
“ Falco uliginosus,” Wilson, Am. Orn. VI, 67. 
“ Falco cyaneus,” Audubon, Orn. Biog. IV, 396. 
