314 Letters, Extracts, Notices, &fc. 



calling Mr, Salvin's attention to the matter^ he at once 

 agreed that this name must be used for the species, which 

 should in future be known as Oceanodroma castro (Harcourt), 

 The synonymy should therefore stand as follows : — 



Thalassidroma castro Harcourt, * A Sketch of Madeira,' 

 p. 123 and p. 166 (1851) ; id. Ann. Mag. N. H. (2) xv. 

 p. 436 (1855) [Desertas Islands, near Madeira], 



Cymochorea cryptoleucura Ridgway, Proc. U.S. Nat, Mus. 

 iv. p. 337 (1882), 



Oceanodroma cryptoleucura Grant, Ibis, 1896, p. 53 



(Salvage Islands; Porto Santo) ; Salvin, Cat. B, Brit. Mus. 



XXV. p, 350 (1896). 



Yours, &c., 



Nat. Hist. Museum, S.W,, W. R. Ogilvie Grant. 



14th March, 1898. 



The Nocturnal Migration of Birds. — It is to be desired 

 that some of our British ornithologists should take up in this 

 country the system of observing the nocturnal migration of 

 birds that has for some years been so successfully followed 

 in America, The mode of doing this, and the general results 

 that have been yet obtained, have lately been described by 

 Mr, Frank M. Chapman in a letter published in ' Science ' *, 

 to which we wish to call the special attention of those in- 

 terested in the subject. If, during the migratory period, 

 a comparatively low-power glass be focussed on the full 

 moon, it is probable that a stream of migrants will be 

 seen passing through the narrow angle subtended by the 

 moon's limb. Thus, as has been described in ' The Auk ' 

 (vol. V. p. 37), at Tenafly, New Jersey, on the night of 

 Sept. 3rd, 1887, Messrs, F. M. Chapman and J, Tatlock, Jr., 

 using a 6^-inch equatorial, saw no less than 262 birds cross 

 the moon's disk between the hours of eight and eleven. The 

 vast majority of them were, of course, unrecognizable ; but 

 in some few cases the peculiarities of these nocturnal 

 wanderers were so marked and so plainly shown that the 

 observers thought themselves able to identify them. 



* "Meteor or Bird?" By Frank M. Chapman 'Science,' n. s. 

 vol. iv, no. 88, Sept. 4th, 1897. 



