Volume I Part 20 (1/2)

_Hab._ Argentina, Paraguay, and E. Brazil.

The most interesting point concerning this species is the very great difference in habits, as well as appearance, existing between the s.e.xes.

In form it resembles the Starling of Europe, but is a trifle smaller and has a shorter tail. The male is black, the upper parts faintly mottled with yellowish grey; there is a straw-coloured stripe over the eye; the throat and breast bright crimson. The female is a smaller bird, and in colour dull fulvous grey, mottled with fuscous; the red tint on the breast scarcely perceptible.

These birds are migratory, and appear everywhere in the eastern part of the Argentine country early in October, arriving singly, after which each male takes up a position in a field or open s.p.a.ce abounding with coa.r.s.e gra.s.s and herbage, where he spends most of the time perched on the summit of a tall stalk or weed, his glowing crimson bosom showing at a distance like some splendid flower above the herbage. At intervals of two or three minutes he soars vertically up to a height of twenty or twenty-five yards to utter his song, composed of a single long, powerful, and rather musical note, ending with an attempt at a flourish, during which the bird flutters and turns about in the air; then, as if discouraged at his failure, he drops down, emitting harsh guttural chirps, to resume his stand. Meanwhile, the female is invisible, keeping closely concealed under the long gra.s.s. But at length, attracted perhaps by the bright bosom and aerial music of the male, she occasionally exhibits herself for a few moments, starting up with a wild, zigzag flight, like a Snipe flushed from its marsh, and, darting this way and that, presently drops into the gra.s.s once more. The moment she appears above the gra.s.s the male gives chase, and they vanish from sight together. Thus, while in colour, habits, language, and even in its manner of soaring up like a rocket to let off its curious melody, the male is the most conspicuous of small birds, the female, acted on in an opposite direction by natural selection, has been, so to speak, effaced.

While flying, they do not look like birds of the same species: the male moves with wings rapidly fluttered, like a Starling, but with a slower, more laborious flight, and without deviating; the female, in her eccentric movements in the air, reminds one of a large moth driven from its hiding-place, and flying about confused with the glare of noon.

The nest is made of dry gra.s.s on the ground, so cunningly concealed that it is most difficult to find. The eggs are four, white, spotted with reddish brown. When they have young, I have never been able to detect the female flying about in search of food.

All through the summer these birds are solitary, but when migrating in the autumn, though many are seen travelling singly, and appear very conspicuous as they fly laboriously in a straight line, at an alt.i.tude of about twenty yards from the surface, others are seen making their journey in small flocks or parties composed of six to a dozen individuals. These are the males. The females travel separately, in twos or threes or singly, flying nearer to the earth, with frequent pauses, when the wings cease beating, and intervals of gliding, also darting occasionally to one side, as if the bird had suddenly taken fright.

101. AMBLYRHAMPHUS HOLOSERICEUS (Scop.).

(SCARLET-HEADED MARSH-BIRD.)

+Amblyrhamphus holosericeus+, _Hudson, P. Z. S._ 1870, p. 114 (Buenos Ayres); _Scl. et Salv. Nomencl._ p. 37; _Durnford, Ibis_, 1877, p. 174 (Buenos Ayres); _Gibson, Ibis_, 1880, p. 18 (Buenos Ayres); _White, P. Z. S._ 1882, p. 602 (Buenos Ayres); _Barrows, Bull. Nutt. Orn. Cl._ viii. p. 135 (Entrerios); _Scl. Cat. B._ xi. p. 351. +Amblyrhamphus ruber+, _Burm. La-Plata Reise_, ii. p.

491 (Entrerios, Santa Fe, Parana).

_Description._--Black; whole head and neck all round, and upper breast and thighs scarlet; bill and feet black: total length 95 inches, wing 45, tail 40. _Female_ similar. _Young_ uniform black.

_Hab._ Paraguay, Uruguay, and Argentina.

Azara named this species _Tordo negro cabeza roxa_; it is also called _Boyero_ (ox-herd) by country people, from its note resembling the long whistle of a drover; and sometimes _Chisel-bill_, from the peculiar conformation of the beak, which is long, straight, and has a broad fine point like a chisel. In both s.e.xes the plumage of the head and neck is scarlet, of an exceedingly brilliant tint, all other parts intense black. These birds are lively, active, and sociable, going in flocks of from half-a-dozen to thirty individuals; they remain all the year, and inhabit the marshes, from which they seldom wander very far, but seek their insect food in the soft decaying rushes. They are common on the swampy sh.o.r.es of the Plata, and when seen at a distance, perched in their usual manner on the summits of the tall rushes, their flame-coloured heads s.h.i.+ne with a strange glory above the sere sombre vegetation of the marshes. The long whistling note above mentioned is their only song, but it varies considerably, and often sounds as mellow and sweet as the whistle of the European Blackbird.

The nest is an ingenious structure of dry gra.s.ses, fastened to the upright stems of an aquatic plant, three or four feet above the water.

The eggs are four, in size and form like those of the English Song-Thrush, spotted somewhat spa.r.s.ely with black on a light blue ground.

The young birds are entirely black at first, and afterwards a.s.sume on the head and neck a pale terra-cotta red, which gradually deepens to vivid scarlet.

102. PSEUDOLEISTES VIRESCENS (Vieill.).

(YELLOW-BREASTED MARSH-BIRD.)

+Pseudoleistes virescens+, _Hudson, P. Z. S._ 1870, p. 549, et 1874, p. 156 (Buenos Ayres); _Scl. et Salv. Nomencl._ p. 37; _Durnford, Ibis_, 1877, p. 175, et 1878, p. 59 (Buenos Ayres); _Gibson, Ibis_, 1880, p. 31 (Buenos Ayres); _White, P. Z. S._ 1882, p. 602 (Buenos Ayres); _Barrows, Bull. Nutt. Orn. Cl._ viii. p. 135 (Entrerios); _Scl. Cat. B._ xi. p. 352. +Leistes anticus+, _Burm.

La-Plata Reise_, ii. p. 491 (Parana).

_Description._--Above and below dark olive-brown; lesser upper wing-coverts, under wing-coverts, and middle of the abdomen yellow; bill black; feet dark brown: total length 95 inches, wing 46, tail 38. _Female_ similar.

_Hab._ S. Brazil, Paraguay, Uruguay, and Argentina.

In both s.e.xes in this species the plumage is deep olivaceous brown, the breast pure yellow. It is active, strong on the wing, sociable and noisy; and being moreover a pretty and elegant bird, very common in settled districts, and with a preference for man's neighbourhood, it is familiar to every one, and has won amongst many compet.i.tors the vernacular name of _Pecho-amarillo_ (Yellow-breast), for with us yellow-breasted species are somewhat numerous. It remains all the year, invariably going about in flocks of from twenty to thirty birds, and feeds on the ground in the fields or on the open plain. While they are feeding, one bird takes up a position on a stalk or thistle-top to keep guard; when he flies down another bird takes his place; if a person approaches, the sentinel gives the alarm, and all the birds fly off in a very close flock, making the air resound with their loud ringing notes.

After feeding, they repair to the trees, where they join their robust voices in a spirited concert, without any set form of melody such as other song-birds possess, but all together, flinging out their notes at random, as if mad with joy. In this delightful hubbub there are some soft silvery sounds. Where they are never persecuted they have little fear of man, but they invariably greet his approach with a loud vigorous remonstrance.

In October the birds break up their companies to pair. Sometimes they breed on the open plain in a large cardoon thistle, but a thick bush or low tree is preferred. The nest is like that of a Thrush, being deep, compactly made of dry gra.s.s and slender sticks, plastered inside with mud, and lined with hair or soft dry gra.s.s. It is, however, deeper and more symmetrical than the Thrush's nest, and it is sometimes plastered with cow-dung instead of with mud. The eggs are four, very long, white, and abundantly spotted with deep red, the spots becoming confluent at the large end.

The Yellow-breast is never seen to quarrel with its fellows or with other birds, and it is possibly due to its peaceful disposition that it is more victimized by the parasitical _Molothrus_ than any other bird. I have frequently found their nests full of parasitical eggs, as many as fourteen and in one case sixteen, eggs in one nest. In some seasons all the nests I found and watched were eventually abandoned by the birds on account of the number of parasitical eggs dropped in them. I have also so frequently found parasitical eggs on the ground under the nest that I believe the Yellow-breast throws out some of these foreign eggs, and in one instance I was quite sure that this had happened. The nest was in a cardoon bush, and contained five eggs--two of the Yellow-breast and three parasitical. These three were of the variety most thickly mottled with red, and consequently closely resembling the eggs of the Yellow-breast. I was surprised to find five more eggs of the Cow-bird on the ground, close together, and about three feet from the bush; and these five eggs were all pure white and unspotted. Naturally I asked, How came these eggs in such a position? They had not fallen from the nest, which was very deep, contained few eggs, and was scarcely thirty inches above the ground. Then they were all white, while those in the nest were mottled. That the eggs had been laid in the nest I felt certain; and the only way I can account for their being in the place where I found them is that the Yellow-breast itself removed them, taking them up in its bill and flying with them to the ground. If I am right, we must believe that this individual Yellow-breast had developed an instinct unusual in the species, which enables it to distinguish, and cast out of its nest, eggs very different from its own--an instinct, in fact, the object of which would be to counteract the parasitical habit of _Molothrus_. What would be the effect of such an instinct should the species acquire it? Doubtless it would be highly prejudicial to the parasitical birds laying white eggs, but favourable to those laying mottled eggs. This would be natural selection operating in a very unusual manner; for the Yellow-breast, or other species, would improve another to its own detriment, since the more the parasitical eggs a.s.similated to its own, the greater would be the likelihood of their being preserved. The perfect similarity of the eggs of _M.