238 NORTH AMERICAN BIRDS. 



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

 growing gradually darker terminally, passing narrowly into dull w^hitish 

 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. Ifale : 

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

 brown. Sab. 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}. Tarsus 4.30 or more ; upper tail-coverts in adult plain white. 



b^. 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 raerelj^ 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. Hah. 

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

 Paraguay, and the Argentine Republic. 



U. urubitinga (Gmel.). Brazilian Urubitinga.^ 



&^ 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 Gurnet. Mexican Urubitinga.^ 



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 /3. ? Rtdgw., Bull. U. S. Geol, & Geog. Surv. Terr. ii. No. 2, 1876, 169. Urubitinga 



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



