[292.] CIRCUS CINEREUS (Vieill.).
(CINEREOUS HARRIER.)
Circus cinereus, Sharpe, Cat. B. i. p. 56; Scl. et Salv. P. Z. S. 1868, p. 143 (Buenos Ayres); iid. Nomencl. p. 118; Burm. La-Plata Reise, ii. p. 439 (Mendoza); Scl. P. Z. S. 1872, p. 536 (Rio Negro); Durnford, Ibis, 1877, p. 38 (Patagonia) et p. 187 (Buenos Ayres), et 1878, p. 397 (Patagonia); Gibson, Ibis, 1879, p. 411 (Buenos Ayres); Barrows, Auk, 1884, p. 30 (Bahia Blanca); Withington, Ibis, 1888, p. 469 (Lomas de Zamora).
Description.—Above bluish grey, with darker mottlings; wing-coverts with obsolete whitish edgings; primaries blackish; tail grey, with four black cross bands, and tipped with white: beneath, throat and neck like the back; abdomen thickly banded with white and rufous bars; under wing-coverts white; bill black; feet yellow; nails black: whole length 18·0 inches, wing 12·0, tail 8·2. Female: rather larger; above dark brown, with lighter brown spots and edgings; throat and fore neck like the back; wings beneath with black cross bands.
Hab. Southern portion of South America.
This Harrier is found throughout the Argentine Republic, and is also common in Patagonia and the Falkland Islands. On the pampas it is, I think, the most common bird of prey, after the excessively abundant Milvago chimango. Like the Chimango, it also prefers an open unwooded country, and resembles that bird not a little in its general appearance, and when in the brown stage of plumage may be easily mistaken for it. In the Falklands it has even acquired the Carrion Hawk’s habits, for Darwin distinctly saw one feeding on a carcass there, very much to his surprise. On the pampas I have always found it a diligent bird-hunter, and its usual mode of proceeding is to drive up the bird from the grass and to pursue and strike it down with its claws. Mr. Gibson’s account of its habits agrees with mine, and he says that “it will raise any small bird time after time, should the latter endeavour to conceal itself in the grass, preferring, as it would seem, to strike it on the wing.” He further says:—“Its flight is low and rather rapid, while if its quarry should double it loses no ground, for it turns something in the manner of a Tumbler Pigeon, going rapidly head over heels in the most eccentric and amusing fashion.”
Probably this Harrier has a partial migration, as a great many are always seen travelling across the pampas in the autumn and spring; many individuals, however, remain all winter.
The nest is made on the ground among long grass, or in reed-beds in marshy places, and the eggs are white blotched with dark red.