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THE FLORA AND FAUNA OF NUYTS ARCHIPELAGO AND THE 

 INVESTIGATOR GROUP. 



No. 9.— THE BIRDS OF THE PEARSON ISLANDS. 



By J. Burton Cleland, M.D. 



[Read May 10, 1923.] 



Considerable interest is attached to the consideration of the land birds 

 inhabiting an island constituted and situated as is Pearson Island. The interest 

 is the same as that attendant on the study of the local faunas of Tasmania and 

 of the islands in Bass Straits. At one time, these were all obviously connected 

 with the adjacent mainland. The group comprising the Pearson Islands now 

 forms the remaining southern outlier of a submerged part of the continent, 

 being distant about 42 miles from the mainland and half this distance from 

 Flinders Island interposed between. Some, all, or none of the land birds now 

 on this group of islands may represent the descendants of those species left 

 behind when the separation occurred. As often happens under such circum- 

 stances, some of the species thus left, if still represented by living forms, might 

 be expected to show some tangible subspecific, if not specific, differences from 

 those on the mainland. Professor Wood Jones' expedition in January, 1923, 

 hoped to obtain a sufficient collection of skins to ascertain whether any such 

 differences existed. Further, it might happen that some species, now extinct 

 on the mainland, still survived on this lonely group. 



Previous visitors to the Pearson Islands have left little record of the birds 

 they observed. Flinders sighted and named the islands, but did not approach 

 near to them. In the sailing directions given in the Australia Directory { 10th 

 edit., vol. i., 1907), it is stated that large flocks of Albatrosses may be seen in 

 its vicinity. The "albatrosses'" referred to seem to be the Pacific Gulls. Mr. 

 Edgar Waite, visiting the island for a few hours on September 27, 1914, 

 noted the presence of Cape Barren Geese, Black Oyster-catchers, Little Penguins, 

 Pacific Gulls, Parrots, Zostcrops, a Thickhead, and Crows, but did not publish 

 his observations. Professor Wood Jones on two recent short visits saw, besides 

 Crested Terns, Silver and Pacific Gulls, Blue Reef-Herons, Cape Barren Geese, 

 Rock-Parrots, and Crows, and what he believed to be several large Green Parrots. 

 No sign of these latter were detected during our stay. 



The birds of the island naturally divide themselves into the sea birds, 

 including all those birds that live in the immediate neighbourhood of our coasts, 

 and the land birds proper. Of the former, with one exception, nothing of 

 particular interest was observed. The exception consisted in the presence on the 

 island of a pair of Red-tailed Tropic Birds, a species hitherto represented 

 in South Australian waters by only one specimen — a female secured on January 

 13, 1919, which had been flying about Grantala Farm, North Shields, near Port 

 Lincoln, for a week and had been captured alive. This was presented to the 

 South Australian Museum. A taxidermist's note states that, on skinning, the 

 bird was "found to have no ears." 



There are three ways in which the presence of land birds may be explained 

 on the Pearson Islands. They may be descendants of the birds originally left 

 there when the islands were separated from the mainland ; they may represent 

 birds blown out to sea by strong winds, especially north winds ; or they may 

 be birds that have deliberately flown south into the Bight and have here made 

 land. 



The species met with on the islands are not peculiar to it. No sound sub- 

 species can be differentiated. We have not then this guide, namely, dift'erentia- 



