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birds with silky plumage peculiar to the Amazon valley. They are often kept in houses, where they get very tame and affectionate ; and they are useful in catching flies and other house insects, which they do with great perseverance and dexterity.
Islands of Tropical South America. These are few in number, and, with one exception, not of much interest. Such islands as Trinidad and Sta. Catherina form parts of South America, and have no peculiar groups of animals. The small islands of Fernando Noronha, Trinidad, and Martin Vaz, off the coast of Brazil, are the only Atlantic islands somewhat remote from land; while the Galapagos Archipelago in the Pacific is the only group whose productions have been carefully examined, or which present features of special interest.
Galapagos Islands.—These are situated on the equator, about 500 miles from the coast of Ecuador. They consist of the large Albemarle island, 70 miles long; four much smaller (18 to 25 miles long), named Narborough, James, Indefatigable, and Chatham Islands; four smaller still (9 to 12 miles long), named Abingdon, Bindloe's, Hood's, and Charles Islands. All are volcanic, and consist of fields of black basaltic lava, with great numbers of extinct craters, a few which are still active. The islands vary in height from 1,700 to 5,000 feet, and they all rise sufficiently high to enter the region of moist currents of air, so that while the lower parts are parched and excessively sterilc, above 800 or 1,000 feet there is a belt of comparatively green and fertile country.
These islands are known to support 58 species of Vertebrates, -- 1 quadruped, 52 birds, and 5'reptiles, the greater part of which are found nowhere else, while a considerable number belong to peculiar and very remarkable genera. We must therefore notice them in some detail.
Mammalia.—This class is represented by a mouse belonging to the American genus Hesperonys, but slightly different from any found on the continent. A true rat (Mus), slightly differing from any Furopean species, also occurs; and as there can be little doubt that this is an escape from a ship, somewhat
changed under its new conditions of life (the genus Mus not being indigenous to the American continent), it is not improbable, as Mr. Darwin remarks, that the American mouse may also have been imported by man, and have become similarly changed.
Birds. Recent researches in the islands have increased the number of land-birds to thirty-two, and of wading and aquatic birds to twenty-three. All the land birds but two or three are peculiar to the islands, and eighteen, or considerably more than half, belong to peculiar genera. Of the waders 4 are peculiar, and of the swimmers 2. These are a rail (Porzana spilonota); two herons (Butorides' plumbea and Nycticorax pauper); a flamingo (Phoenicopterus glyphorhynchus); while the new aquatics are a gull (Larus fuliginosus), and a penguin (Spheniscus mendiculus).
The land.birds are much more interesting. All except the birds of prey belong to American genera which abound on the opposite coast or on that of Chili a little further south, or to peculiar genera allied to South American forms. The only species not peculiar are, Dolichonyx oryzivorus, a bird of very wide range in America and of migratory habits, which often visits the Bermudas 600 miles from North America, and Asio accipitrinus, an owl which is found almost all over the world. The only geñera not exclusively American are Buteo and Strix, of each of which a peculiar species occurs in the Galapagos, although very closely allied to South American species. There remain 10 genera, all either American or peculiar to the Galapagos; and on these we will remark in systematic order.
1. Mimus, the group of American mocking-thrushes, is represented by three distinct and well-marked species. 2. Dendrveca, an extensive and wide-spread genus of the wood-warblers (Mniotiltidæ), is represented by one species, which ranges over the greater part of the archipelago. The genus is especially abundant in Mexico, the Antilles, and the northern parts of
1 Mr. Salvin, who has critically examined the ornithological fauna of these islands, has kindly corrected my MS. List of the Birds, his valuable paper in the Transactions of the Zoological Society not having been published in time for me to make use of it.
tropical America, only one species extending south as far as Chili. 3. Certhidea, a peculiar genus originally classed among the finches, but which Mr. Sclater, who has made South American birds his special study, considers to belong to the Corebida, or sugar-birds, a family which is wholly tropical. Two species of this genus inhabit separate islands. 4. Progne, the American martins (Hirundinidæ), is represented by a peculiar species. 5. Geospizu, a peculiar genus of finches, of which no less than eight species occur in the archipelago, but not more than four in any one island. 6. Camarhynchus (6 sp.) and 7. Cactornis (4 sp.) are two other peculiar genera of finches; some of the species of which are confined to single islands, while others inhabit several. 8. Pyrocephalus, a genus of the American family of tyrant-flycatchers (Tyrannidæ), has one peculiar species closely allied to T. rubineus, which has a wide range in South America. 9. Myiarchus, another genus of the same family which does not range further south than western Ecuador, has also a representative species found in several of the islands. 10. Zenaida, an American genus of pigeons, has a species in James Island and probably in some of the others, closely allied to a species from the west coast of America.
It has been already stated that some of the islands possess peculiar species of birds distinct from the allied forms in other islands, but unfortunately our knowledge of the different islands is so unequal and of some so imperfect, that we can form. no useful generalizations as to the distribution of birds among the islands themselves. The largest island is the least known; only one bird being recorded from it, one of the mocking-thrushes found nowhere else. Combining the observations of Mr. Darwin with those of Dr. Habel and Prof. Sundevall, we have species recorded as occurring in seven of the islands Albemarle island has but one definitely known species ; Chatham and Bindloe islands have 11 each ; Abingdon and Charles islands 12 each; Indefatigable island and James island have each 18 species. This shows that birds are very fairly distributed over all the islands, one of the smallest and most remote (Abingdon) furnishing as many as the much larger Chatham Island, which is also the nearest