38 U. S. p. K. R EXP. AND SUEVEYS — ZOOLOGY — GENERAL REPORT. 



Only inhabits tlie southern States of North America, and jjrobably Mexico and Central 

 America. In the southern division of this continent this bird is represented by another species 

 with which it has been confounded. 



ROSTEHAMUS, 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. 



KOSTRIIAMUS SOCIABILIS, Vieillot. 



Herpelolhercs sociabilis, Vieill. Nouv. Diet. XVIII, 318, (1817.) 

 Cymindis Ifucopygius, Spix, Av. Bras. I, p. 7, (1824.) 

 Rostrhamus niger, Lesson, Traite, I, 56, Q831.) 

 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 otlier 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. — Front 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, 7| inches. Male rather smaller. 



Hah. — Florida, (Mr. Edward Harris, Dr. Heerniann.) 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. Krider. 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 large ; 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 i n n £e u s . 



The Harrier—The Marsh Hawk. 



Falco hudsonius, Linn. Syst. Nat. I, 128, (1766.) 

 Falco uliginosus, Gm. Syst. Nat. I, 278, (1788.) 

 Falco uropogistus, Daodin, Traite d'Orn. II, 110, (1800.) 

 " Falco «/tjinosus," Wilson, Am. Orn. VI, 67. 

 " Fulco cyanetts," AvuvDoN, Orn. Biog. IV, 396. 



