15. OCEANODROMA HORNBYI {Gray). 



(HORNBY'S FORK-TAILED PETREL.) 

 (Plate 10.) 



Thalassidroma horribyi, Gray, P. Z. S., 1853, p. 62 ; Lawrence in Baird, Cassin and 



Lawrence, Birds N. Amer., p. 829 (1863). 

 Oceanodroma horribyi, Bp., Consp. Av., II., p. 195 (1856) ; Salvin, Cat. Birds Brit. 



Mus., XXV., p. 356 (1896). 

 Procellaria horribyii, Gray, Handl. Birds, III., p. 105, No. 10,871 (1871). 



Cinereus : pileo nigricante : subtus albus, fascia prsepectorali lata schistacea. 



This species is easily recognised by the dark collar across the fore-neck, the under- 

 surface being otherwise pure white, and the back a dingy grey. It is only represented 

 in museums by the single type-specimen in the National Collection, described by Mr. 

 George Robert Gray. It was procured by Admiral Hornby when he was in command 

 of the Pacific Station, and is said to have been obtained in the seas off the north-western 

 coast of America. During the sixty years which have elapsed since its original discovery, 

 no second specimen has been obtained, and in the " Check-list " of North American 

 Birds, it is placed in the " Hypothetical List " as if the correctness of the habitat were 

 not credited. Unfortunately, after the manner of the times, no original label was 

 attached to the specimen, but there is no reason why the habitat should be doubted. 



Mr. E. W. Nelson observes : — " While on my way to and from the Aleutian Islands, 

 a Petrel, conspicuous by its white collar and under-surface, was seen repeatedly, and, 

 although none were secured, yet it was identified by its peculiar pattern of coloration. 

 These birds were seen both in May and October, while crossing a part of the Pacific, 

 some 500 miles broad, bordering the Aleutian chain " {Bep. Nat. Hist. Coll. Alaska, No. 3, 

 p. 64, 1887). 



Mr. Henshaw (I. s. c.) suggests that the Petrels observed by Mr. Nelson may have 

 been CEstrelata fisheri of Ridgway, which has also been procured in the North Pacific 

 Ocean, near Alaska. 



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