POLYBORUS. 125 
the arboreal habits, distinguish Jdycter; and the linear nostril and the form of the 
cere, which is described as “‘vertical in outline and nearly straight,” are said to separate 
Polyborus from Milvago. 
Two well-defined species of Polyborus are known, viz.: P. tharus (Molina), which 
inhabits the greater part of South America, and is replaced in the northern portions 
of the latter Continent, and throughout Central America even to the Southern United 
States, by P. cheriway (Jacq.) ; two closely allied forms of the latter have been treated 
as distinct—P. lutosus, Ridgw., of the island of Guadalupe, off Lower California, and 
P. pallidus, Nelson, of the Tres Marias Islands. 
The Polybori are all terrestrial in their habits, usually frequenting open plains, and 
feeding largely on carrion, like the Turkey Vultures, with which they often associate. 
They are generally known by the name of ‘Caracara,” but in Central America the 
natives call them ‘“ Quebra’-hueso ” * (bone-breaker). 
1. Polyborus cheriway. 
Falco cheriway, Jacq. Beitr. p. 17, t. 41. 
Polyborus cheriway, Cab. in Schomb. Reis. Guiana, iii. p. 741°; Sharpe, Cat. Birds Brit. Mus. i. 
p. 83°; Ridgw. Bull. U.S. Geol. & Geogr. Surv. i. p. 457*; Sumichrast, La Nat. v. 
p. 235°; Salv. Cat. Strickl. Cat. p. 509°; Boucard, P. Z.S. 1883, p. 4577; Belding, Pr. 
U.S. Nat. Mus. vi. p. 344°; Nutting, Pr. U.S. Nat. Mus. vi. pp. 377°, 389"; Ferrari- 
Perez, Pr. U.S. Nat. Mus. ix. p. 168"; Zeledon, An. Mus. Nac. Costa Rica, 1887, p. 125: 
Herrera, La Nat. (2) i. pp. 177, 8320"; Bendire, Life Hist. N. Amer. Birds, i. p. 315"; 
Visher, Bull. U.S. Dep. Agric. no. 3, p. 128"; Cherrie, Auk, 1892, p. 328"; Jouy, Pr. 
U.S. Nat. Mus. xvi. p. 788 °°; Chapman, Bull. Amer. Mus. Nat. Hist. x. p. 35. 
Polyborus brasiliensis, Sw. Phil. Mag. new ser. i. p. 366 (nec Gm.) ”. 
Falco plancus, Wag). Isis, 1831, p. 516 (nec Gm.) ”*. 
Polyborus tharus, Scl. P.Z.S. 1857, p. 211 (mec Molina)”; 1859, p. 3868”; Scl. & Salv. Ibis, 
1859, p. 214; P.Z.S. 1870, p. 838”; Owen, Ibis, 1861, p. 67 *. 
Polyborus audubonii, Cassin, Pr. Ac. Phil. 1865, p. 2; Lawr. Ann. Lyc. N. Y. ix. pp. 132”, 
207"; v. Frantz. J. f. Orn. 1869, p. 367; Grayson, Pr. Bost. Soc. N. H. xiv. p. 268 
(pt.) ®. 
- Polyborus tharus, var. audubonii, Lawr. Mem. Bost. Soc. N. H. ii. p. 308 (pt.) *; Bull. U.S. Nat. 
Mus. no. 4, p. 43. 
Polyborus vulgaris, Dugés, La Nat. i. p. 188% (nec Spix). ; 
Nigricans ; pilei plumis cristatis lanceolatis ; interscapulii plumis extus albido regulariter fasciatis ; torque 
cervicali lactescenti-albo, maculis vel fasciis parvis nigris notato; supracaudalibus medianis uropygio 
concoloribus, lateralibus autem albis, vix nigro fasciatis; rectricibus albidis, brunneo vel nigro trans- 
fasciatis, et apicem versus nigricantibus, fasciam latam terminalem formantibus; externis vero nigricantibus, 
vel albo late indentatis; remigibus nigricantibus, primariis longioribus in medio grisescentibus, irregulariter 
brunneo marmoratis vel fasciatim notatis: subtus nigricans, facie laterali et gutture toto cum colli 
lateribus lactescenti-albis ; prepectore et pectore summo ochrascentibus, nigro cordatim fasciatis ; 
abdomine imo, crisso et subcaudalibus ochrascenti-albis ; subalaribus et axillaribus nigricantibus: rostro 
flavicante, mandibula plumbescente, cera et regione orbitali lete aurantiacis; pedibus flavis; iride flava. 
* “ Quebrantahuesos,” according to Sumichrast. 
