Page:The birds of Tierra del Fuego - Richard Crawshay.djvu/268

138 Sterna cassinii, ''Abbott. Ibis,'' p. 166, 1861.

Habitat.—South America, on the east from Brazil, on the west from Peru to Cape Horn; the Falkland Islands; South Georgia Islands; South Shetland Islands.

♂,♀, Useless Bay, 5th Jan., 1905. Iris—black; bill and legs—bright scarlet.

The Swallow Tern is common on such parts of the coast as are favourable to its existence. I have never remarked it inland. It appears to prefer a rocky coast with here and there a spit of shingle to an open flat shore. Much of its time it rests on large rocks, surrounded by water. Its expanse of wing is so enormous in proportion to its size as to appear to burden its flight, entailing vastly unnecessary^ labour in moving the shortest possible distance. It would be hard to find a more delicately and beautifully coloured creature in its soft silver grey and snow-white plumage, with long sharp needle -like scarlet bill and tiny scarlet legs and feet. It is, however, anything but pleasant in its attitude to man—it is ever noisy and aggressive after the manner of its kind.

I found a small breeding colony on a spit of shingle on the southern shore of Useless Bay on January 10th. There were about one hundred birds, and numbers of nests placed close together in an area some fifty yards long by three or four yards broad parallel with and only a few feet above high tide mark. The usual number of eggs in each nest was two, laid in a slight depression in the bare shingle. I took about a dozen, representative of more than half a dozen distinct types. Unfortunately, with the exception of three, all proved too far incubated for preservation. No pair of eggs of all I saw exactly resembled any other pair. Not only did they differ vastly in shape, but in ground colour and markings. They were variously ovate, short ovate, elongate ovate, or ovate pyriform. In ground colour they ranged from pale greenish blue to ochre brown. The markings