Oeder PROCELLAETIFOEMBS.] 



[Family PUFFINIDiE. 



(ESTRELATA AXILLARIS. 



(SALVIN'S PETEBL.) 



(Estrelata axillaris, Salvin, Ibis, 1893, p. 264. 



This is a very interesting addition to our list of native species. In the collection of birds made 

 by the late Mr. Hawkins at the Chatham Islands, there were two specimens of a Petrel allied to 

 (Estrelata cooki, but differing in several marked characters, notably in having black axillary 

 plumes. Mr. Salvin states that "the skins were not quite adult, but were marked male and female. 

 The birds had been shot on the south-east island on the 8th May, 1892." 



A specimen of this rare Petrel, hitherto recorded only as from the Chatham Islands, 

 was picked up, not long since, on the Wairarapa plains, where also stray individuals of 

 Prion clesolatus are often found, driven inland by stress of weather. 



The plumage of this Petrel is so singularly like that of Prion that we may, I think, regard it 

 as a case of mimicry for protective purposes. The two genera are perfectly distinct, but, as we get 

 better acquainted with the species, we shall probably find that this Petrel hunts with the commu- 

 nities of Prion that are so common in our seas. I confess I was completely ueceived myself, for 

 the moment, when the late Mr. Salvin handed me a specimen for exam nation without saying 

 anything. What protection is gained in the struggle for existence by this curious resemblance 

 of plumage can only be a matter of speculation till we know more about the habits and general 

 economy of these birds. But why are the axillaries black ? 



(ESTRELATA PHILLTP1. 



(PHILLIPS' PETEEL.) 



(Estrelata phillipi, Gray, Ibis, 1862, p. 46. 



Captain Hutton, who has made a special study of the Petrels of the Southern hemisphere, and 

 probably knows more about them than any of us, considers this to be a distinct species. In his 

 paper already referred to ( l P^ - ^ool. Soc.,' 1893, p. 755) he says : — 



I have little doubt but that this bird is the same species as the Norfolk Island Petrel of Governor 

 Phillips. It approaches another species, (E. neglecta, but can be distinguished by the shape of the white on 

 the inner web of the primaries as well as by its colours. Having examined three specimens, which, although 

 varying slightly in colour, are constant in this respect, I have no hesitation in admitting it as distinct. 

 Mr. Cheeseman informs me that he did not see this species at the Kermadecs, and knows nothing about its 

 breeding habits ; but Mr. Bell sent him specimens with the Summer Mutton-birds, so that it probably breeds 

 with them from September to November. The Norfolk-Island Petrel is said to form burrows in the sand. 





