Argentine Ornithology Volume Ii Part 19

It comes as far south as Buenos Ayres, but is only a summer visitor there, and very scarce. Having seen but little of it myself, I can only repeat Azara's words concerning it. He says it is common in Paraguay, going in pairs or families, and perches and roosts on trees, and when flying flaps its wings more rapidly than other Herons. It makes its nest on a tree, and lays two clear blue eggs.

On the Lower Uruguay, Mr. Barrows likewise found this species "not common." It was only seen a few times in November. "Though most resembling the Night-Heron they were active by day, and when disturbed flew rapidly away from the streams and swamps towards the dry woods and hills."

320. BUTORIDES CYANURUS (Vieill.).

(LITTLE BLUE HERON.)

+Butorides cyanurus+, _Scl. et Salv. Nomencl._ p. 125; _iid. P. Z.

S._ 1868, p. 145 (Buenos Ayres); _Durnford, Ibis_, 1878, p. 62 (Buenos Ayres); _Barrows, Auk_, 1884, p. 271 (Entrerios).

+Butorides striata+, _Baird, Brew., et Ridgw. Water-B. N. A._ i.

p. 50.

_Description._--Glaucous grey; beneath ashy; crown crested, black, with greenish gloss; neck beneath with a band of ferruginous spots, more or less mixed with black; wings greenish cinereous; wing-coverts edged with whitish; bill dusky green, feet ashy yellowish: whole length 140 inches, wing 65, tail 25. _Female_ similar.

_Hab._ South America.

The Little Blue Heron, though widely distributed, is not anywhere a common bird. I have always seen them singly, for it loves a hermit-life, and the feeding-ground it prefers is a spot on the borders of a marshy stream shut in and overshadowed on all sides by trees and tall rushes.

There the bird sits silent and solitary on a projecting root or dead branch; or stands motionless and knee-deep in the water, intent on the small fry it feeds on. For whole months it will be found every day in the same place. When intruded on in its haunt it erects the feathers of its head and neck, looking strangely alarmed or angry, and flies away uttering a powerful harsh grating cry.

Its nesting-habits I do not know; but Mr. Barrows says that it undoubtedly breeds near Concepcion on the Lower Uruguay, where it is abundant in spring and summer.

321. ARDETTA INVOLUCRIS (Vieill.).

(VARIEGATED HERON.)

[Plate XVII.]

[Ill.u.s.tration: ARDETTA INVOLUCRIS.]

+Ardetta involucris+, _Scl. et Salv. Nomencl._ p. 125; _iid. P. Z.

S._ 1869, p. 634; _Hudson, P. Z. S._ 1875, p. 624 (Buenos Ayres); _Durnford, Ibis_, 1877, p. 189, et 1878, p. 62 (Buenos Ayres); _Gibson, Ibis_, 1880, p. 159 (Buenos Ayres); _Barrows, Auk_, 1884, p. 271 (Entrerios).

_Description._--Above pale fulvous; narrow stripe on the nape black; front, stripe on the back of the neck, bend of wing, and outer secondaries chestnut-red; back striped with black; wing-feathers dark cinereous with red tips: beneath paler, nearly white on the belly; neck, breast, and flanks with brown stripes, darker in the centres; bill yellow; feet brown: whole length 130 inches, wing 50, tail 15.

_Hab._ Paraguay and Argentina.

The Variegated Heron is the least of the family to which it belongs, its body being no bigger than that of the Common Snipe; but in structure it is like other Herons, except that its legs are a trifle shorter in proportion to its size and its wings very much shorter than in other species. The under plumage is dull yellow in colour, while all the other parts are variegated with marks of fuscous and various shades of brown and yellow. The body is extremely slim, and the lower portion of the neck covered with thick plumage, giving that part a deceptively ma.s.sive appearance. The perching faculty, possessed in so eminent a degree by all Herons, probably attains its greatest perfection in this species, and is combined with locomotion in a unique and wonderful manner. It inhabits beds of rushes growing in rather deep water; very seldom, and probably only accidentally, does it visit the sh.o.r.e, and only when driven up does it rise above the rushes; for its flight, unlike that of its congeners, is extremely feeble. The rushes it lives amongst rise, smooth as a polished pipe-stem, vertically from water too deep for the bird to wade in; yet it goes up to the summit and down to the surface, moving freely and briskly about amongst them, or runs in a straight line through them almost as rapidly as a Plover can run over the bare level ground. Unless I myself had been a witness of this feat, I could scarcely have credited it; for how does it manage to grasp the smooth vertical stems quickly and firmly enough to progress so rapidly without ever slipping down through them?

The Variegated Heron is a silent solitary bird, found everywhere in the marshes along the Plata, as also in the reed-beds scattered over the pampas. It breeds amongst the rushes, and lays from three to five spherical eggs, of a rich lively green and beautiful beyond comparison.

The nest is a slight platform structure about a foot above the water, and so small that there is barely s.p.a.ce enough on it for the eggs, which are large for the bird. When one looks down on them they cover and hide the slight nest, and being green like the surrounding rushes they are not easy to detect.

When driven up the bird flies eighty or a hundred yards away, and drops again amongst the rushes; it is difficult to flush it a second time, and a third time it is impossible. A curious circ.u.mstance is that where it finally settles it can never be found. As I could never succeed in getting specimens when I wanted them, I once employed some Gaucho boys, who had dogs trained to hunt young Ducks, to try for this little Heron.

They procured several specimens, and said that without the aid of their dogs they could never succeed in finding a bird, though they always marked the exact spot where it alighted. This I attributed to the slender figure it makes, and to the colour of the plumage so closely a.s.similating to that of the dead yellow and brown-spotted rushes always found amongst the green ones; but I did not know for many years that the bird possessed a marvellous instinct that made its peculiar conformation and imitative colour far more advantageous than they could be of themselves.

One day in November 1870, when out shooting, I noticed a Variegated Heron stealing off quickly through a bed of rushes thirty or forty yards from me; he was a foot or so above the ground, and went so rapidly that he appeared to glide through the rushes without touching them. I fired, but afterwards ascertained that in my hurry I missed my aim. The bird, however, disappeared at the report; and thinking I had killed him, I went to the spot.

It was a small isolated bed of rushes I had seen him in; the mud below and for some distance round was quite bare and hard, so that it would have been impossible for the bird to escape without being perceived; and yet, dead or alive, he was not to be found. After vainly searching and researching through the rushes for a quarter of an hour I gave over the quest in great disgust and bewilderment, and, after reloading, was just turning to go, when, behold! there stood my Heron on a reed, no more than eight inches from, and on a level with, my knees. He was perched, the body erect, and the point of the tail touching the reed grasped by its feet; the long slender tapering neck was held stiff, straight and vertically; and the head and beak, instead of being carried obliquely, were also pointing up. There was not, from his feet to the tip of his beak, a perceptible curve or inequality, but the whole was the figure (the exact counterpart) of a straight tapering rush: the loose plumage arranged to fill inequalities, and the wings pressed into the hollow sides, made it impossible to see where the body ended and the neck began, or to distinguish head from neck or beak from head. This was, of course, a front view; and the entire under surface of the bird was thus displayed, all of a uniform dull yellow, like that of a faded rush. I regarded the bird wonderingly for some time; but not the least motion did it make. I thought it was wounded or paralyzed with fear, and, placing my hand on the point of its beak, forced the head down till it touched the back; when I withdrew my hand, up flew the head, like a steel spring, to its first position. I repeated the experiment many times with the same result, the very eyes of the bird appearing all the time rigid and unwinking like those of a creature in a fit. What wonder that it is so difficult, almost impossible, to discover the bird in such an att.i.tude! But how happened it that while repeatedly walking round the bird through the rushes I had not caught sight of the striped back and the broad dark-coloured sides? I asked myself this question, and stepped round to get a side view, when, _mirabile dictu_, I could still see nothing but the rush-like front of the bird! His motions on the perch, as he turned slowly or quickly round, still keeping the edge of the blade-like body before me, corresponded so exactly with my own that I almost doubted that I had moved at all. No sooner had I seen the finishing part of this marvellous instinct of self-preservation (this last act making the whole complete), than such a degree of delight and admiration possessed me as I have never before experienced during my researches, much as I have conversed with wild animals in the wilderness, and many and perfect as are the instances of adaptation I have witnessed. I could not finish admiring, and thought that never had anything so beautiful fallen in my way before; for even the sublime cloud-seeking instinct of the White Egret and the typical Herons seemed less admirable than this; and for some time I continued experimenting, pressing down the bird's head and trying to bend him by main force into some other position; but the strange rigidity remained unrelaxed, the fixed att.i.tude unchanged. I also found, as I walked round him, that, as soon as I got to the opposite side and he could no longer twist himself on his perch, he whirled his body with great rapidity the other way, instantly presenting the same front as before.

Finally I plucked him forcibly from the rush and perched him on my hand, upon which he flew away; but he flew only fifty or sixty yards off, and dropped into the dry gra.s.s. Here he again put in practice the same instinct so ably that I groped about for ten or twelve minutes before refinding him, and was astonished that a creature to all appearance so weak and frail should have strength and endurance sufficient to keep its body rigid and in one att.i.tude for so long a time.

Our figure of this species (Plate XVII.) is taken from a skin in Sclater's collection, which was procured by Mr. F. Withington in the Lomas de Zamora in 1883.

322. TIGRISOMA MARMORATUM (Vieill.).

(MARBLED TIGER-BITTERN.)

+Garza jaspeada+, _Azara, Apunt._ iii. p. 100. +Ardea marmorata+, _Vieill. Nouv. Dict._ xiv. p. 415. +Tigrisoma marmoratum+, _Berl.

J. f. O._ 1887, p. 30. +Tigrisoma fasciatum+, _Salvin, Ibis_, 1880, p. 363 (Salta)? +Tigrisoma brasiliense+, _White, P. Z. S._ 1882, p. 624 (Corrientes)?

_Description._--Above greenish grey, finely crossed by narrow fulvous vermiculations; head and neck uniform rusty red: beneath greyish fulvous; breast flammulated with white; flanks and under wing-coverts black with white cross bars: whole length 180 inches, wing 105, tail 40.

_Hab._ Paraguay and N. Argentina.

Graf v. Berlepsch has recently shown that the Tiger-Bittern of Paraguay differs from _Tigrisoma brasiliense_ (which it generally resembles in plumage) in having the base of the lower mandible partly feathered as in _T. fasciatum_. It is probable that the Argentine Tiger-Bittern belongs to the same form, but we have not yet met with adult specimens of it. It occurs in the northern provinces of the Republic, and was obtained by White in Corrientes, and by Durnford in Salta.

323. NYCTICORAX OBSCURUS, Bp.

(DARK NIGHT-HERON.)

+Nycticorax obscurus+, _Scl. et Salv. Nomencl._ p. 126; _Durnford, Ibis_, 1878, p. 03 (Buenos Ayres), et p. 399 (Patagonia); _Gibson, Ibis_, 1880, p. 158 (Buenos Ayres). +Ardea gardeni+, _Burm. La-Plata Reise_, ii. p. 508 (Parana). +Nycticorax gardeni+, _White, P. Z. S._ 1882, p. 624 (Buenos Ayres and Salta); _Barrows, Auk_, 1884, p. 271 (Entrerios).

_Description._--Above cinereous; front white; head, nape, and scapulars greenish black; elongated nuchal plumes white: beneath paler, whitish on throat and middle of belly; bill black; feet flesh-colour: whole length 260 inches, wing 120, tail 48, tarsus 32. _Female_ similar.

_Hab._ Southern half of South America.

In the Argentine Republic the Night-Heron lives in communities, and pa.s.ses the hours of daylight perched inactive on large trees or in marshes on the rushes, and when disturbed by day they rise up with heavy flappings and a loud _qua-qua_ cry. At sunset they quit their retreat, to ascend a stream or seek some distant feeding-ground, and travel with a slow flight, bird succeeding bird at long intervals, and uttering their far-sounding, hoa.r.s.e, barking night-cry.

Where the flock lives amongst the rushes, in places where there are no trees, the birds, by breaking down the rushes across each other, construct false nests or platforms to perch on. These platforms are placed close together, usually where the rushes are thickest, and serve the birds for an entire winter.

The breeding-habits of the Night-Heron have already been described in the account of the _Ardea egretta_.

In the Falkland Islands, where Captain Abbott discovered a heronry (_cf._ Ibis, 1861, p. 157), their breeding-habits are the same as on the pampas.

Fam. x.x.xVI. CICONIIDae, or STORKS.

The Storks const.i.tute a small but well-defined family of the Order Herodiones, allied to the Ardeidae, but distinguished by the elevated hallux, their non-pectinated middle claw, and the absence of powder-down patches in the plumage. They are divisible into two sub-families--the true Storks, and the Wood-Ibises (Tantalinae). Two of the former group and one of the latter occur within our limits, and two of these three species range throughout tropical America up to the Southern United States.

324. MYCTERIA AMERICANA, Linn.

(THE JABIRU.)