Argentine Ornithology Volume I Part 19

96. MOLOTHRUS BADIUS, Vieill.

(BAY-WINGED COW-BIRD.)

[Plate VI. Fig. 1.]

+Molothrus badius+, _Burm. La-Plata Reise_, ii. p. 495 (Parana and Tuc.u.man). _Scl. et Salv. Nomencl._ p. 37; _Hudson, P. Z. S._ 1874, p. 163 (Buenos Ayres); _Durnford, Ibis_, 1877, p. 174 (Buenos Ayres); _Scl. Cat. B._ xi. p. 338.

_Description._--Dull grey, beneath rather paler; wings chestnut; tips of primaries, inner portions of secondaries, and tail blackish; bill and feet black: total length 76 inches, wing 35, tail 30.

_Female_ similar.

_Hab._ Argentina, Paraguay, and Bolivia.

In this species the s.e.xes are alike; the plumage of the body is grey-drab colour, with a black spot between the eye and beak; tail dark, the quills cinnamon-colour; beak and legs black. Azara describing it under the name of _Tordo pardo roxiso_, says it is a rare bird, so that it has probably greatly increased since his time, as it is now quite common in the Plata district.

The Bay-wings usually go in small flocks, numbering from ten to thirty individuals, and are not migratory, but in winter they travel about a great deal from place to place without extending their journeys more than a few miles in any direction. They are fond of coming about houses, and are frequently seen pecking at the fresh meat hanging out of doors; and, like other birds of the same tribe, feed chiefly on the ground.

They spend a great portion of their time on trees, are familiar with man and inactive, and in their motions singularly slow and deliberate. Their language is varied. Curiosity or alarm is expressed by trilling notes, and before quitting a tree all the birds of a flock ceremoniously invite each other to fly with long clear notes, powerful enough to be heard a quarter of a mile away.

They also sing a great deal in all seasons, the song being composed of soft, clear, rather sweet notes, variously modulated, uttered in a leisurely manner, and seeming to express a composed frame of mind, all the birds in a flock singing in concert. During the cold season the flock always finds some sheltered sunny spot on the north side of a woodpile or hedge, where they spend several hours every day, sitting still and singing in their usual quiet, soft style.

Their extreme sociability affects their breeding-habits, for sometimes the flock does not break up in spring, and several females lay in one nest together; but whether the birds are paired or practice a promiscuous intercourse, I have not been able to discover. They have a great partiality for the large domed nests made by the _Anumbius acuticaudatus_, called Lenatero in the vernacular. One summer a flock of about ten Bay-wings took possession of a Lenatero's nest on one of my trees, and after a few days I took fourteen eggs from it. Though the birds hopped, chirping round me, manifesting great solicitude, the eggs were quite cold, and had I left them many more would have been laid, no doubt; but as they were piled up three or four deep in the nest they could never have been hatched.

As a rule, however, the flock breaks up into pairs; and then a neat, well-made nest is built in the fork of a branch, lined with horsehair; or, oftener still, a Lenatero's nest is seized, the Bay-wings fighting with great spirit to get possession, and in it, or on it, their own nest is made. Like their relations, the Common Cow-bird, they seem strongly attracted by domed nests, and yet shrink from laying in the dark interior; as a rule when they have captured a Lenatero's nest they break a hole in the side and so admit the light and form an easy entrance.

One summer a pair of Bay-wings attacked a Lenatero's nest on one of my trees; the fighting was kept up for three or four days, and then at the foot of the tree I found five young Lenateros, fully fledged, which had been pecked to death and thrown out of the nest.

The eggs of the Bay-wing are five in number, nearly round, and densely marked with dusky reddish brown.

Once I observed two young Bay-wings following a Yellow-breast (_Pseudoleistes virescens_) with their usual peculiar hunger-cry, and while I watched them they were fed several times by their foster-parents. Naturally I concluded that the Bay-winged Cow-bird is sometimes parasitical on other species, but I never saw anything afterwards to confirm me in that belief, and I believe now that I was mistaken, and that the young Bay-wings were not _real_ Bay-wings, but the young of _Molothrus rufoaxillaris_.

97. AGELaeUS THILIUS (Mol.).

(YELLOW-SHOULDERED MARSH-BIRD.)

+Agelaeus thilius+, _Burm. La-Plata Reise_, ii. p. 492 (Mendoza, S.

Juan, Catamarca); _Scl. et Salv. Nomencl._ p. 37; _Durnford, Ibis_, 1876, p. 159 (Buenos Ayres), 1877, p. 33 (Chupat), p. 174 (Buenos Ayres), et 1878, p. 394 (Chupat); _White, P. Z. S._ 1882, p. 602 (Buenos Ayres); _Doring, Exp. al Rio Negro, Zool._ p. 40 (Colorado); _Barrows, Bull. Nutt. Orn. Cl._ viii. p. 134 (Entrerios); _Scl. Cat. B._ xi. p. 343.

_Description._--Black; lesser upper and under wing-coverts yellow; bill and feet black: whole length 55 inches, wing 36, tail 27.

_Female_: above pale brown striated with black; distinct superciliaries white; beneath paler, cineraceous white with black striations; smaller, and bill shorter.

_Hab._ S. Peru, Chili, Paraguay, and Argentina.

This bird is abundant everywhere on the pampas, and does not migrate, but inhabits marshy situations in summer, building its nest amongst the rushes, and in winter ranges over the country. The male is entirely of an intense black, except the shoulders, which are pure yellow; the female is dull grey with fuscous markings, and, as was long ago remarked by Azara, the grey-plumaged are very much more numerous than the black individuals. The young birds are like the females, and possibly do not acquire the full black plumage until the second year, which would account for the great number of grey birds.

These birds are extremely sociable, being seen in flocks all the year round, even during the breeding-season; in winter a great many males separate themselves from the females, and are found a.s.sociating together in flocks of from thirty to forty individuals.

They feed on the ground, keeping to the moist borders of marshes during summer; they avoid woods, but occasionally alight on trees, where they all sing in concert. The song, when an individual is heard singing alone, is, though limited in its range, very sweet, some of the notes being remarkable for their purity and expression. The bird sits on a rush or stalk while singing, and makes a long pause after every note or two, as if to make the most of its limited repertory. There is in the song one rich full note, which, to my mind, is unequalled for plaintive sweetness, and I am therefore surprised that Azara says only of this species that it sings pa.s.sably well--'_canta razonablemente_.'

The nest is neatly made of dry gra.s.ses, and attached to the rushes growing in the water. The eggs are four, pointed, and spotted at the larger end with dull brown and black on a white ground.

98. AGELaeUS FLAVUS (Gm.).

(YELLOW-HEADED MARSH-BIRD.)

+Xanthosomus flavus+, _Scl. et Salv. P. Z. S._ 1869, p. 632 (Buenos Ayres); _iid. Nomencl._ p. 37; _Durnford, Ibis_, 1878, p. 59 (Buenos Ayres); _Doring, Exp. al Rio Negro, Zool._ p. 41 (Carhue); _Barrows, Bull. Nutt. Orn. Cl._ viii. p. 134 (Entrerios). +Agelaeus flavus+, _Scl. Cat. B._ xi. p. 346.

_Description._--Black; head and rump, bend of the wing, and body beneath bright yellow; bill and feet black: whole length 67 inches, wing 42, tail 32. _Female_: above brown, slightly striated; eyebrows, rump, and body beneath yellowish; bill and feet brown.

_Hab._ Paraguay, Uruguay, and Argentina.

Azara called this bird _Cabeza amarilla_, or Yellow-head. It is found throughout the eastern provinces of the Argentine country, ranging south to about the thirty-sixth degree of lat.i.tude, and is also common in the Banda Oriental.

The dull-plumaged birds are always very much more numerous than the bright-coloured males, though Azara strangely a.s.serts that the s.e.xes are alike. In Buenos Ayres, where it is called "Naranjo" by the country people in allusion to its orange tints, it is very well known on account of its yellow plumage, which looks so wonderfully brilliant in the sunshine, and its partiality for cultivated districts, where it follows the plough to pick up worms, and frequents the orchard to sing, a.s.sociating with the common Cow-bird and Yellow-breast. It remains all the year, and is very sociable, going in flocks of from twenty to fifty individuals, which when they settle on the trees all sing in concert, pouring out their few peculiar notes with great power and emphasis.

Even in the breeding-season these companies do not always break up, and frequently several pairs have nests near together. The nest is usually built in a cardoon thistle, two or three feet above the ground, and is made of dry gra.s.s. The eggs are four, pointed, white or with a bluish tinge, and speckled irregularly with deep brown, the spots being closer and sometimes confluent at the broad end.

Concerning the plumage of this species Mr. Barrows writes:--"Late in March, 1881, we found this species in large flocks on the Pigue, and it was a beautiful sight to see a hundred or more fluttering about among the snowy plumes of the pampas gra.s.s, and displaying their rich black and yellow dress. Unlike most other birds obtained at that time, their plumage seemed nearly as bright and fresh as in summer."

99. AGELaeUS RUFICAPILLUS, Vieill.

(RED-HEADED MARSH-BIRD.)

+Agelaeus ruficapillus+, _Scl. Cat. B._ xi. p. 347. +Xanthosomus ruficapillus+, _Scl. et Salv. P. Z. S._ 1869, p. 159 (Buenos Ayres); _iid. Nomencl._ p. 37; _White, P. Z. S._ 1882, p. 602 (Salta, Catamarca). +Chrysomus frontalis+, _Burm. La-Plata Reise_, ii. p 492 (Parana).

_Description._--Glossy blue-black; crown of head and middle of throat dark chestnut; bill and legs black: whole length 75 inches, wing 37, tail 29.

_Hab._ Argentina and Paraguay.

The s.e.xes are alike in this species: the crown of the head is rufous, and with this exception the whole plumage a rich glossy blue-black. The beauty of the bird and its delicate, plaintive voice would no doubt make it a favourite with man if he saw more of it, only it lives and breeds in marshes, and does not come near his habitations. The Red-heads are gregarious and migratory. The flock can scarcely be said to break up in the breeding-season, as the birds all make their nests near together in the reeds. The nest is placed about one or two feet above the water, is about six inches in depth, and made of leaves and aquatic gra.s.ses woven together. The eggs are four, pointed, with a white or pale bluish ground, and spotted with black at the larger end.

The song of the Red-head is quite unique in character. It begins with a low, hollow-sounding note, then the voice changes to a clear, sorrowful tone, rising in a rapid succession of short notes, and falling again in longer ones.

After the breeding-season the birds fly about in flocks of two or three hundred individuals, and sing in concert on the trees.

Their chirp has a peculiar metallic sound, and can be imitated by tapping on the edge of a copper bell with the finger-nail.

100. LEISTES SUPERCILIARIS, Bp.

(RED-BREASTED MARSH-BIRD.)

+Leistes superciliaris+, _Hudson, P. Z. S._ 1870, p. 333 (Buenos Ayres); _Scl. et Salv. Nomencl._ p. 38; _Durnford, Ibis_, 1877, p. 175 (Buenos Ayres); _White, P. Z. S._ 1882, p. 602 (Salta); _Barrows, Bull. Nutt. Orn. Cl._ viii. p. 136 (Entrerios); _Scl.

Cat. B._ xi. p. 349. +Trupialis guianensis+, _Burm. La-Plata Reise_, ii. p. 490 (Banda Oriental).

_Description._--Brownish black; superciliaries pale brown; bend of the wing and body beneath from the chin to the middle of the belly bright scarlet; bill and legs black; length 70 inches, wing 40, tail 25. _Female_ pale brown, above variegated with black, below stained with red on the breast; flanks and lower belly striated with black; tail cinereous brown, with black cross bars.