Beprtnted from The Atjk. Vol. XLi; April, 1924. 



Editor of 'The Auk:' 



In 'The Auk' for January, 1924 (Vol. XLI, pp. 68-71) there is "A Review 

 of the West Indian Black Swifts" by Ludlow Griscom. In his comments 

 upon sexual variation in this species Mr. Griscom makes certain state- 

 ments with which I take issue. I have no personal knowledge of the West 

 Indian subspecies of Nephoecetes niger, but the statements to which I 

 object are made as generalizations covering the species as a whole, and 

 they assuredly do not apply to the race with which I am familiar, the 

 North American subspecies, Nephoecetes niger boreaUs. 



Mr. Griscom describes certain variations of color and markings as dis- 

 tinguishing males and females, and remarks of such supposed sexual varia- 

 tion that "this has already been correctly described by Mr. Ridgway" 

 (Birds of North and Middle America, part V, 1911, pp. 703-710). He 

 says further that "Hartert (Catalogue of Birds, Brit. Mus., XVI, 1892, 

 p. 94 [ sic; correctly, 494]) errs in regarding the adults as similar, and the 

 birds with light tips to the feathers below as immature." This last 

 assertion of error is altogether too positive and sweeping a statement of 

 what is really no more than Mr. Griscom's opinion. My own conviction 

 is that Hartert is correct. 



There is an article on this subject by Frank M. Drew (Bull. Nutt. Orn 



