294 



AVIFAUNA OF LAYSAN, ETC. 



STEGANOPODES. 



92. PHAETHON RUBRICAUDA (Bodd.). 



Phaethon rubric auda, Grant, Cat. B. Brit. Mus. xxvi. p. 451 (1898) {anteh, Pt. I. pp. 33, 34) ; AVilson & Evans, 

 Av. Hawaii, pt. vii. (1899). 



Since writing the first paragraph of the present work, I have received a magnificent 

 series of the Red-tailed Tropic-hird f rom Professor Schauinslarid, collected on Laysan in July, 

 August, and September. This series contains young in various stages. The downy chick 

 is not at all pure white nor uniform grey. The upperside is hrownish grey, the down heing 

 white at the hase ; face, breast, and abdomen almost pure white. The iris is light blue ; bill 

 blackish blue; lores bare and blackish blue. The feathers of the first plumage appear first 

 on the wings and scapulars. The upperside of the young in first plumage is broadly barred 

 with black ; the primaries white, with black shafts and black longitudinal spots along the 

 shafts near the tips, of varying sizes. The bill is blackish. 



Palmer sent me two skins, male and female, which he obtained on Niihau 27.7.1893. 

 According to Wilson, " It breeds in several places in the group, especially on Kauai and 

 Niihau, and chooses holes in almost inaccessible cliffs wdierein to deposit its eggs." 

 Mr. Perkins " considers this species much more uncommon " than the white-tailed 

 species. 



Comparing my series of Red-tailed Phaethons from various localities, I find them to 

 belong to two well-marked forms. While my series from Laysan and Niihau and two caught 

 in the Pacific Ocean at lat. 21° 10' N., long. 115°, belong to a smaller form, with narrower 

 snd slenderer beak, shorter wings, and with a very slight rosy tinge, the birds from the 

 Kermadec group, Norfolk and Lord Howe's Islands — in short from the islands to the north of 

 New Zealand — are larger, with a thicker, stronger and longer bill, and have a very pronounced 

 rosy-red tinge in their plumage, especially on the wings. This beautiful red tint is so strong 

 that even in skins which are about four or five years older than those recently collected by 

 Schauinsland this colour is much stronger. 



Mr. Grant (I. c.) attributes the " pinkish tint " to freshly-killed specimens. This is true 

 in so far as that tint fades more or less in skins, especially when not kept in the dark, but it 

 does not in the least account for the differences in the birds from various localities, as 

 described above. 



