Mr. Salvin founded his C. altirostris upon Durnford’s specimens, but Graf v. Berlepsch is of opinion that this species is the “Habia verde” of Azara, and should consequently bear the name “viridis” of Vieillot. This is perhaps correct, but at the same time it would only make fresh confusion to transfer to this species the name hitherto usually applied to the preceding bird. We prefer, consequently, to let it stand under Mr. Salvin’s name “altirostris.”
[ Fam. VIII. HIRUNDINIDÆ, or SWALLOWS.]
The cosmopolitan family of Swallows, of which about eighty species are known, is well developed in the New World, where some thirty representatives occur in various parts. In Argentina the occurrence of eight Swallows has been recorded. Three of them belong to the group of Purple Martins (Progne), which is restricted to the New World, and of the remainder four are members of genera entirely restricted to the Neotropical Region. The genus Petrochelidon, of which one species is met with in La Plata, has alone representatives in the Eastern Hemisphere.
[25.] PROGNE FURCATA, Baird.[3]
(PURPLE MARTIN.)
Progne purpurea, Hudson, P. Z. S. 1872, p. 548 (Patagonia); Scl. P. Z. S. 1872, p. 605; Scl. et Salv. Nomencl. p. 14; Durnford, Ibis, 1877, p. 32 (Chupat), 1878, p. 392 (Central Patagonia); White, P. Z. S. 1882, p. 595 (Buenos Ayres). Progne elegans, Barrows, Bull. Nutt. Orn. Cl. viii. p. 89 (Bahia Blanca). Progne furcata, Baird, Rev. A. B. p. 278; Sharpe, Cat. A. B. x. p. 175.
Description.—Uniform deep purple-blue; on each side of the back a small concealed tuft of white feathers; tail-feathers black, washed with blue: total length 7·7 inches, wing 5·55, tail 3·3. Female: upper parts dull purple; head, neck, and lower parts blackish brown.
Hab. Argentina and Patagonia.
The Purple Martin is occasionally seen in the eastern provinces of La Plata when migrating, but has not been found nesting anywhere so far north as Buenos Ayres. I met with it breeding at Bahia Blanca on the Atlantic coast, and on the Rio Negro, where it is very common. It arrives in Patagonia late in September, and leaves before the middle of February. On the 14th of that month I saw one flock flying north, but it was the last. It breeds in holes under the caves of houses or in walls, and its nest is like that of P. chalybea; but many also breed in holes in the steep banks of the Rio Negro. They do not, however, excavate holes for themselves, but take possession of natural crevices and old forsaken burrows of the Burrowing Parrot (Conurus patachonicus). In size, flight, manners, and appearance the Purple Martin closely resembles the following species, the only difference being in the dark plumage of the under surface. The language of the two birds is also identical; the loud excited scream when the nest is approached, the various other notes when the birds sweep about in the air, and the agreeably modulated and leisurely-uttered song are all possessed by the two species without the slightest difference in strength or intonation. This circumstance appears very remarkable to me, because, though two species do sometimes possess a few notes alike, the greater part of their language is generally different; also because birds of the same species in different localities vary more in language than in any other particular. This last observation, however, applies more to resident than to migratory species.
[3] [I here follow Mr. Sharpe in considering the Purple Martin of Argentina and Patagonia separable from the closely allied northern species of North America. But I am altogether sceptical about its occurrence in Chili, which Dr. Philippi expressly [diaries] (P. Z. S. 1868 p. 534) and for which I know of no good authority.—P. L. S.]