Mr. Barrows observed it on the Lower Uruguay, and writes:—“It feeds largely if not exclusively on fish, nearly every specimen having their remains (and nothing else) in their stomachs.” It would be very interesting to learn how it captures its prey.
[295.] BUTEO SWAINSONI, Bp.
(SWAINSON’S BUZZARD.)
[Plate XVI.]
Buteo swainsoni, Scl. et Salv. Nomencl. p. 118; Withington, Ibis, 1888, p. 469 (Lomas de Zamora); Baird, Brew., et Ridgw. N. A. B. iii. p. 263. Buteo obsoletus, Sharpe, Cat. B. i. p. 184. Buteo albicaudatus, Scl. et Salv. P. Z. S. 1869, p. 634 (Buenos Ayres).
Description.—Above blackish brown; scapulars slightly variegated with rufous; upper tail-coverts white, tinged with rufous; tail dark greyish brown, crossed by several ill-defined blackish bars: beneath white or pale ochraceous; a broad band covering the whole breast reddish brown; bill black; feet yellow; claws black: whole length 20·0 inches, wing 15·0, tail 8·5. Female similar, but larger.
Hab. North and South America.
The figure given herewith (Plate XVI.) represents a fine adult female specimen of this Buzzard, obtained by Mr. Frank Withington at Lomas de Zamora, on the 4th of February, 1886, and now in Sclater’s collection.
Swainson’s Buzzard is a North-American species, which has only recently been ascertained to occur in the southern part of the Western Hemisphere. Full details concerning it are given in the standard work on “North-American Land-birds,” to which we have referred above. Messrs. Baird, Brewer, and Ridgway divide the species into two subspecies, “swainsoni” and “oxypterus” to the latter of which they refer the southern specimens, but they acknowledge that it is “difficult to express points of absolute difference” between these subspecies.