In the evening they are often seen hovering at a height of forty feet above the surface, and continuing to do so fully a minute or longer without altering their position. They do not drop the whole distance at once on their prey, but descend vertically, tumbling and fluttering as if wounded, to within ten yards of the earth, and then, after hovering a few seconds more, glide obliquely on to it. They prey on every living creature not too large to be overcome by them. Sometimes when a mouse is caught they tear off the head, tail, and feet, devouring only the body.

The hind quarters of toads and frogs are almost invariably rejected; and inasmuch as these are the most fleshy and succulent parts, this is a strange and unaccountable habit. They make an easy conquest of a snake eighteen inches long, and kill it by dealing it blows with the beak, hopping briskly about it all the time, apparently to guard themselves with their wings. They prey largely on the common _Coronella anomala_, but I have never seen one attacking a venomous species. When they have young many individuals become destructive to poultry, coming about the houses and carrying off the chickens and ducklings by day. In seasons of plenty they destroy far more prey than they can devour; but in severe winters they come, apparently starving, about the houses, and will then stoop to carry off any dead animal food, though old and dried up as a piece of parchment. This I have often seen them do.

Though the Owls are always on familiar terms with the Vizcachas (_Lagostomus trichodactylus_) and occasionally breed in one of their disused burrows, as a rule they excavate a breeding-place for themselves. The kennel they make is crooked, and varies in length from four to twelve feet. The nest is placed at the extremity, and is composed of wool or dry gra.s.s, often exclusively of dry horse-dung.

The eggs are usually five in number, white, and nearly spherical; the number, however, varies, and I have frequently found six or seven eggs in a nest. After the female has begun laying the birds continue carrying in dry horse-dung, until the floor of the burrow and a s.p.a.ce before it is thickly carpeted with this material. The following spring the loose earth and rubbish is cleared out, for the same hole may serve them two or three years. It is always untidy, but mostly so during the breeding-season, when prey is very abundant, the floor and ground about the entrance being often littered with excrements, green beetle-sh.e.l.ls, pellets of hair and bones, feathers of birds, hind quarters of frogs in all stages of decay, great hairy spiders (_Mygale_), remains of half-eaten snakes, and other unpleasant creatures that they subsist on.

But all this carrion about the little Owl's disordered house reminds one forcibly of the important part the bird plays in the economy of nature.

The young birds ascend to the entrance of the burrow to bask in the sun, and receive the food their parents bring; when approached they become irritated, snapping with their beaks, and retreat reluctantly into the hole; and for some weeks after leaving it they make it a refuge from danger. Old and young birds sometimes live together for four or five months. I believe that nine-tenths of the Owls on the pampas make their own burrows, but as they occasionally take possession of the forsaken holes of mammals to breed in, it is probable that they would always observe this last habit, if suitable holes abounded, as on the North-American prairies inhabited by the marmot. Probably our Burrowing-Owl originally acquired the habit of breeding in the ground in the open level regions it frequented; and when this habit (favourable as it must have been in such unsheltered situations) had become ineradicable, a want of suitable burrows would lead it to clean out such old ones as had become choked up with rubbish, to deepen such as were too shallow, and ultimately to excavate for itself. The mining instinct varies greatly in strength, even on the pampas. Some pairs, long mated, only begin to dig when the breeding-season is already on them; others make their burrows as early as April--that is six months before the breeding-season. Generally both birds work, one standing by and regarding operations with an aspect of grave interest, and taking its place in the pit when the other retires; but sometimes the female has no a.s.sistance from her partner, and the burrow then is very short. Some pairs work expeditiously and their kennel is deep and neatly made; others go about their task in a perfunctory manner, and begin, only to abandon, perhaps half a dozen burrows, and then rest two or three weeks from their unprofitable labours. But whether industrious or indolent, by September they all have their burrows made. I can only account for Azara's unfortunate statement, repeated since by scores of compilers, that the Owl never constructs its own habitations, by a.s.suming that a century ago, when he lived and the country was still very spa.r.s.ely settled, this Owl had not yet become so abundant or laid aside the wary habit the aborigines had taught it, so that he did not become very familiar with its habits.

291. GLAUCIDIUM NANUM (King).

(PYGMY OWL.)

+Glaucidium nanum+, _Scl. et Salv. Nomencl._ p. 117; _Burm. La-Plata Reise_, ii. p. 441; _Scl. P. Z. S._ 1872, p. 549 (Rio Negro); _White, P. Z. S._ 1883, p. 41 (Cordova); _Doring, Exp. al Rio Negro_, p. 49 (Rio Negro); _Sharpe, Cat. B._ ii. p. 190.

_Description._--Above dull reddish brown, mottled with concealed spots and bars of ochraceous buff; scapulars with an ashy tinge; head more rufous and longitudinally streaked; whitish collar on the hind neck; wings dark brown, banded with rufous; tail dark brown, with about ten rufous bars, and tipped with whitish; cheeks and chin pure white, the latter divided by a dark brown throat-band from the white fore neck; abdomen white, streaked with dark brown: whole length 80 inches, wing 38, tail 29. _Female_ similar, but rather larger.

_Hab._ La Plata, Patagonia, and Chili.

This diminutive Owl, which barely reaches eight inches in length, and is light brown and grey in colour, was discovered by Captain King in 1827 in the neighbourhood of the Straits of Magellan. I met with it on the Rio Negro in Patagonia, but saw very little of it. It struck me that, like the Burrowing-Owl, it is not very strictly nocturnal, for I observed it in the daytime perched in exposed situations.

In 1882 White met with it in Cosquin, in Cordova, and made the following important note on its habits:--"It causes the naturalist much amus.e.m.e.nt to watch the habits of this pretty little Owl, that, perched perfectly motionless on a branch, utters such a sirenic cry as to attract little birds in great numbers. They are observed to cl.u.s.ter round it, all the while fluttering and in great excitement, charmed by some fascination.

After waiting a while the Owl suddenly pounces upon the nearest for its victim."

I also observed little birds mobbing it, when it perched in a conspicuous place in the daytime, as they always mob small birds of prey, but was not so fortunate as to hear the "sirenic cry" with which the Cordova bird fascinates its victims. One has heard this yarn of a "sirenic cry" before, of other species, for it is a very common myth.

That an Owl should now be fitted with the old melodious cap seems strange; and Mr. White is in error when he says that this habit in our bird "causes the _naturalist_ much amus.e.m.e.nt."

Order VII. ACCIPITRES.

Fam. x.x.xII. FALCONIDae, or FALCONS.

The diurnal birds of prey of the family Falconidae found in the Neotropical Region number about 110 species, of which 22 are at present known to occur within the limits of the present work. It is probable, however, that many additional species of this group will be hereafter added to the Argentine list.

As is usually the case with the Accipitres, most of the species have an extensive distribution.

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 180 inches, wing 120, tail 82.

_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 carca.s.s 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 gra.s.s 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 gra.s.s, 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 gra.s.s, or in reed-beds in marshy places, and the eggs are white blotched with dark red.

293. CIRCUS MACROPTERUS, Vieill.

(LONG-WINGED HARRIER.)

+Circus macropterus+, _Scl. et Salv. Nomencl._ p. 118; _iid. P. Z.

S._ 1868, p. 143 (Buenos Ayres); _Doring, Exp. al Rio Negro_, p.

50 (Rio Colorado). +Buteo macropterus+, _d'Orb. Voy., Ois._ p.

112 (Buenos Ayres). +Circus maculosus+, _Sharpe, Cat. B._ i. p.

62. +Circus megaspilus+, _Gould, Zool. Voy. Beagle_, iii. p. 29 (Uruguay).

_Description._--Above black; frontal band, superciliaries, and upper tail-coverts white; edge of facial ruff spotted with white; wing- and tail-feathers grey, with black cross bands: beneath white, chest and throat black, with some white streaks; under wing-coverts white, with narrow blackish cross bands: whole length 200 inches, wing 170, tail 100. _Female_ similar, but larger.

_Hab._ South America.

This Harrier is also found in the Republic, but is not so common as the former species.

294. ASTURINA PUCHERANI, Verr.

(PUCHERAN'S HAWK.)

+Asturina pucherani+, _Scl. et Salv. Ex. Orn._ pl. 89, p. 177; _iid.

Nomencl._ p. 118; _iid. P. Z. S._ 1869, p. 634 (Buenos Ayres); _Durnford, Ibis_, 1877, p. 187 (Buenos Ayres); _Barrows, Auk_, 1884, p. 30 (Entrerios); _Withington, Ibis_, 1888, p. 469 (Lomas de Zamora); _Sharpe, Cat. B._ i. p. 205.

_Description._--Above dark brown; upper tail-coverts fulvous barred with brown; wings deep chestnut, barred and broadly tipped with black; tail fulvous, with four blackish cross bands: beneath, abdomen pale ochraceous, barred across with rufous; throat blackish, with slight white stripes; breast ochraceous, with narrow black shaft-stripes; thighs ochraceous, narrowly barred with orange-rufous; bill black; feet dark yellow: whole length 180 inches, wing 110, tail 82. _Female_ similar, but rather larger.

_Hab._ South Brazil, Paraguay, and Argentina.

This brown-plumaged, short-winged, and exceedingly vociferous Hawk is common in the woods along the sh.o.r.es of the Plata and its tributaries, and is never found far removed from water. It perches on the summit of a tree, and sits there motionless for hours at a time, and at intervals utters singularly long loud cries, which become more frequent and piercing when the bird is disturbed, as by the approach of a person.

Its flight is rapid and irregular, the short blunt wings beating unceasingly, while the bird pours out a succession of loud vehement broken screams.

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.)