BIRDS OF NORTH AND MIDDLE AMERICA 205 



Plumage ^ and coloration.- — Loral region with numerous very fine or 

 slender antrorse bristles, the anterior and especially the uppermost 

 ones strongly recurved; chin and malar apex also with long, but 

 nearly straight antrorse bristles; plumage in general full and rather 

 soft, the feathers of pileum cuneate and acuminate, those of nape 

 and hindneck broadly cuneate and acuminate, those of other upper- 

 parts with tips broadly rounded and distinctly outlined, those of 

 underparts similar but softer and more blended; plumage of thighs 

 moderately developed. Adults with head and underparts cinnamon 

 or light cinnamon-rufous, the latter barred with dusky, the pileum 

 streaked with the same; wings mostly brighter cinnamon-rufous, the 

 remiges brownish black distally; tail blackish brown narrowly tipped 

 with grayish; crossed near middle by a band of dull grayish white, 

 the basal portion mottled with light rufous. Young with head, neck, 

 and breast pale ochraceous to bufFy whitish, the first streaked, the 

 last longitudinally spotted with dusky bro\\Ti, the tail dusky trans- 

 versely mottled or narrowly and irregularly barred with dull grayish. 



Range. — Continental Tropical America, from southern Mexico to 

 Paraguay and Argentina. (Monotypic.) 



KEY TO THE RACES^OF HETEROSPIZIAS MERIDIONALIS 



a. Wing under 420 mm. (Panama to Paraguay and southeastern Brazil). 



H. m. raeridionalis (p. 205) 

 aa. Wing over 420 mm. (Argentina) H. m. rufulus (extralimital) « 



HETEROSPIZIAS MERIDIONALIS MERIDIONAUS (Latham) 



Rufous-headed Hawk 



Adults (fourth year; sexes alike except in size).— Forehead, crown, 

 occiput, and nape orange-cimiamon, the feathers with blackish shaft 

 streaks, the streaks becoming broader and more conspicuous on the 



* According to Nitzsch, the pterylosis of Heterospizias resembles that of Buieo, 

 but the external branch of the pectoral stem of the inferior tract is only half free, 

 as in Haliaeetus. Remiges 25. 



6 Heterospizias meridionalis rufulus (Vieillot). — Circus rufulus Vieillot, 

 Nouv. Diet. Hist. Nat., iv. 1816, 466 (based on Gavilan del Estero avanelado 

 Azara; near city of Corrientes). — Falco rutilans Temminck and Laugier, Rec. 

 Planches Col., i, livr. 5, 1824, pi. 24, part. — Buteo rutilans d'Orbigny, Voy. Am^r. 

 M6rid., iv, pt. 3, 1837, 104, part. — Asturina rutilans Burmeister, Journ. fiir Orn., 

 1860, 242 (Tucumdn). — Urubitinga meridionalis Sclater and Salvin, Proc. Zool. 

 Soc. London, 1869, 634 (Buenos Aires); Durnford, Ibis, 1880, 362 (Salta),— 

 Heterospizias meridionalis Sharpe, Cat. Birds Brit. Mus., i, 1874, 160, part; 

 Hartert and Venturi, Nov. Zool., xvi, 1909, 238 (habits); Dabbene, Orn. Arg., 

 1910, 243 (distr.); Brabourne and Chubb, Birds South Amer., i, 1912, 66, part. — 

 Heterospizias meridionalis australis Swann, Auk, xxxviii, 1921, 359; Monogr. Birds 

 Prey, i, pt. 5, 1926, 344; Wetmore, U. S. Nat. Mus. Bml. 133, 1926, 114; Peters, 

 Check-list Birds of World, i, 1931, 226. — Heterospizias meridionalis rufulus 

 Steullet and Deautier, Cat. Sist. Aves. Argentina, i, pt. 2, 1936, 409 (syn., distr.). 



