BUTEO. 59 
B. albicaudatus exhibits many changes of plumage, all apparently due to age. The 
adult is grey above and pure white beneath up to the base of the bill, but examples 
having the upper portion of the throat grey are not uncommon. Mingled with these are 
slightly younger birds which still have the dark throat and the whole belly, flanks, and 
tibie banded with narrow dusky bars; this phase is preceded by a plumage in which 
the under surface is pale fawn-colour, with large subterminal spots on each feather. 
The tail is shorter than in any other species of Buteo found in Central America; it 
varies from an ashy grey with two cross-bars, to white with a broad subterminal bar 
and a few narrow transverse bands on the basal portion. All these stages of plumage 
are represented in our series from the Lower Rio Grande and various parts of Mexico, 
Central and South America. Professor Allen has separated the Rio Grande bird as 
Buteo albicaudatus sennetti, a race of the true B. albicaudatus of South Brazil, but, 
with the series before us, we find no distinctive characters for definition. A set of 
skins from British Guiana are matched, so far as we can see, by a similar set from the 
north, the birds in both districts undergoing the same changes of plumage. 
Buteo albicaudatus is a resident in Southern Texas and the valley of the lower Rio 
Grande, and breeds abundantly in this portion of the Gulf States of North America °. 
Though not yet recorded from the valley of Mexico itself, it is, according to 
Sumichrast *, widely distributed in that country. In Guatemala we found it on the 
southern slope of the cordillera, but there, as in Costa Rica, it is rare. Arcé sent us 
specimens from Calovevora and Chitra in the State of Panama, thence its range extends 
to Colombia, Venezuela, and Guiana, through Central and Eastern Brazil to Argentina 
and Paraguay. 
Shy and wary in habit, it breeds abundantly in Texas, the nest being placed in low 
bushes. The eggs, which are white with a few small blotches of light brown or 
drab ®, are generally two, rarely three, in number. We found B. albicaudatus feeding 
on beetles and locusts in Guatemala ?1, but it is also said to eat snakes, frogs, rabbits, 
and quails °. 
Section C. Majores. Ale remigibus externis quatuor in pogonio interno excisis. 
3. Buteo abbreviatus. 
Buteo albonotatus, Gray, List Accip. p. 17 (1844) (deser. nulla)’; Scl. P. Z. S. 1860, p. 2537; 
v. Frantz. J. f. Orn. 1869, p. 368°; Salv. Ibis, 1873, p. 428+; Lawr. Mem. Bost. Soc. 
N. H. ii. p. 302°. 
Buteo abbreviatus, Cab. in Schomb. Guiana, iii. p. 739°; Salv. Cat. Strickl. Coll. p. 486’; 
Ferrari-Perez, Pr. U.S. Nat. Mus. ix. p. 167°; Herrera, La Nat. (2) 1. pp. 176, 320°; 
Bendire, Life Hist. N. Amer. Birds, p. 228, t. 7. fig. 6°; A. O. U. Check-l. N. Amer. Birds, 
p. 182"; Fisher, Bull. U.S. Dep. Agr. no. 3, p. 71”. 
Tachytriorchis abbreviatus, Sharpe, Cat. Birds Brit. Mus, i. p. 163”. 
gx 
