238 NORTH AMERICAN BIRDS. 



extended, and colors generally darker. Young: Tail hoary grayish, 

 growing gradually darker terminally, passing narrowly into dull whitish 

 or rusty at tip, and crossed by numerous narrow and very indistinct bars 

 of darker, these becoming gradually obsolete toward base of tail ; gen- 

 eral color of plumage brownish black, the lower parts more or less varied 

 with whitish, buffy, or ochraceous. Downy young : Upper half of head 

 dark sooty brown, becoming nearly black around eyes ; hind-neck, upper 

 back, and wings lighter sooty brown, fading gradually into dull brownish 

 buff on posterior upper parts and buffy whitish on lower parts. Male : 

 Wing 14.50-16.75, tail 7.50-9.00, tarsus 3.30-3.60, middle toe 1.55-1.80. 

 Female: Wing 17.00-17.75, tail 8.25-10.30, culmen .95-1.05, tarsus 3.30- 

 3.70, middle toe 1.60-1.80. Nest on low trees or bushes (usually a 

 yucca). Eggs 2-4, 2.37 X 1-89, white, more or less blotched with reddish 

 brown. Hob. Whole of Middle America, north to southern Texas ; por- 

 tions of eastern South America. 



341. B. albicaudatus VIEILL. White-tailed Hawk, 



GENUS URUBITINGA LESSON. (Page 223, pi. LXX., fig. 2.) 



Species. 



COMMON CHARACTERS. Adults, uniform plumbeous-black, the upper tail-cov- 

 erts, band across tip of tail, and other white bands on tail, pure white. Young : 

 Above varied with blackish brown and ochraceous, the former prevailing ; lower 

 parts ochraceous or pale buffy, striped with dusky, the thighs barred with the 

 same ; tail crossed by numerous narrow bands of blackish and light grayish, mixed 

 with white. 



a 1 . Tarsus 4.30 or more ; upper tail-coverts in adult plain white. 



b l . Tail, of adult, with only two to three white bands, the broadest one more 

 than 2.50 (2.60-4.50) wide ; thighs often without white bars, these when 

 present never (?) conspicuous ; under wing-coverts destitute of white 

 markings, or else merely speckled with white; wing 16.50-18.00, tail 

 11.75-12.00, culmen 1.30, tarsus 4.90-5.00, middle toe 1.90-2.10. Hab. 

 Tropical America, north to Costa Rica (and Nicaragua ?), south to Chili, 

 Paraguay, and the Argentine Republic. 



U. urubitinga (GMEL.). Brazilian Urubitinga. 1 



b 2 . Tail, of adult, with three to four (usually three) white bands, the broadest 

 one not more (usually much less) than 2.00 (1.20-2.00) wide; thighs 

 always marked (usually conspicuously barred) with white ; under wing- 

 coverts always (?) barred or speckled with white; wing 15.15-16.50, tail 

 10.50-11.50, culmen 1.10-1.35, tarsus 4.30-4.85, middle toe 1.60-1.90. 

 Hab. Guatemala and southern Mexico, north to Yera Cruz, Tehuante- 

 pec, and Mazatlan. U. ridgwayi GTTRNHY. Mexican Urubitinga. 2 



1 Falco urubitinga GMEL., S. N. i. 1788, 265. Falco zonurus SHAW, Gen. Zool. vii. 1809, 62. Urubitinga 

 zonura SCL., Trans. Zool. Soc. Lond. 1858, 262. 



2 Urubitinga zonura ft. ? RIDGW., Bull. U. S. Geol. & Geog. Surv. Terr. ii. No. 2, 1876, 169. Urubitinga 



ridgwayi GURNEY, List Diurn. B. Prey, 1884, 77, 148. 



