The Cachilas are resident, living in couples all the year round, the sexes being faithful. Several pairs frequent a small area, and sometimes they unite in a desultory flock; but these gatherings are not frequent. In the evening, at all seasons, immediately after the sun has set, the Cachilas all rise to a considerable height in the air and fly wildly about, chirping for a few minutes, after which they retire to roost.
When approached they frequently rise up several feet from the ground and flutter in the air, chirping sharply, with breast towards the intruder. This is a habit also found in Synallaxine species inhabiting the grassy plains. But, as a rule, the Cachilas are the tamest of feathered creatures, and usually creep reluctantly away on their little pink feet when approached. If the pedestrian is a stranger to their habits they easily delude him into attempting their capture with his hat, so little is their fear of man.
To sing, the Cachila mounts upwards almost vertically, making at intervals a fluttering pause, accompanied with a few hurried notes. When he has thus risen to a great height (but never beyond sight as Azara says) he begins the descent slowly, the wings inclining upwards; and, descending, he pours forth long impressive strains, each ending with a falling inflection or with two or three short throat-notes as the bird pauses fluttering in mid-air, and then renewed successively until, when the singer is within 3 or 4 feet of the earth, without alighting he reascends as before to continue the performance. It is a very charming melody, and heard always on the treeless plains when there is no other bird-music, with the exception of the trilling and grasshopper-like notes of a few Synallaxine species. But in character it is utterly unlike the song of the Sky-Lark with its boundless energy, hurry, and abandon; and yet it is impossible not to think of the Sky-Lark when describing the Cachila, which, in its manners, appearance, and in its habit of soaring to a great height when singing, seems so like a small copy of that bird.
The Cachila rears two broods in the year; the first is hatched about the middle of August, that is, one to three months before the laying-season of other Passerine species. By anticipating the breeding-season their early nests escape the evil of parasitical eggs; but, on the other hand, frosty nights and heavy rains are probably as fatal to as many early broods as the instinct of the Molothrus bonariensis, or Cow-bird, is to others at a later period.
The second brood is reared in December, the hottest month, and in that season a large proportion of their nests contain parasitical eggs.
The nest is placed in a slight hollow in the ground, under a tussock of grass, and is sometimes elaborately made and lined with horsehair and fine grass, and sometimes with a few materials loosely put together. During the solstitial heats I have frequently found nests with frail shades, built of sticks and grass, over them, the short withered grass affording an insufficient protection from the meridian sun. The eggs are four, elongated, with a dirty white and sometimes a dull bluish ground, thickly spotted with dusky brown and drab. In some eggs the spots are confluent, the whole shell being of a dull brownish-drab colour.
The manners of this species, where I have observed it, are always the same; it lives on the ground on open plains, where the herbage and grass is short, and never perches on trees. The song varies considerably in different districts.
[16.] ANTHUS FURCATUS, d’Orb. et Lafr.
(FORKED-TAIL PIPIT.)
Anthus furcatus, d’Orb. Voy. p. 227 (Patagonia); Darwin, Zool. Voy. ‘Beagle’, iii. p. 85 (La Plata); Sclater, Ibis, 1878, p. 364; Döring, Exp. al Rio Negro, Zool. p. 37 (Azul, Carhué-pampas); Sharpe, Cat. B. x. p. 605.