A rare petrel
This short note by F. N. Chasen reports on a specimen of Swinhoe’s Fork-tailed Petrel (Oceanodroma m. monorhis) collected at Horsburgh Lighthouse, 33 miles east of Singapore, in October 1921, and discusses the species’ range in Malaysian waters (p. 255).
Summary
Chasen reviews the known records of O. monorhis in the region, noting that Kuroda (1922) had overlooked a 1911 record from Java (Semarang) and that Robinson and Kloss (1922) had already added the species to the Malay Peninsula fauna based on a specimen from One Fathom Bank Lighthouse. He further cites records extending the range to Siam and Sumatra waters (p. 255).
The note includes field observations by collector P. de Fontaine of a flock of at least twelve petrels skimming the water during a N.E. blow on 28 October 1921, and notes that the lighthouse keepers were familiar with the species and had previously failed to preserve specimens alive. Chasen compares the two Singapore Museum specimens, finding them markedly different in plumage tone from the bird figured by Salvin but consistent with the written description, and provides measurements for the Horsburgh bird (length 205 mm., spread 490 mm., wing ≥165 mm.). He concludes by distinguishing O. monorhis from the only other small black petrels in the region, Oceanites oceanicus and Puffinus leucomelas (p. 256).