556 Oberholser, Notes on N. A. Birds. \cm 



LOct. 



NOTES ON NORTH AMERICAN BIRDS. 

 IX. 



BY HARRY C. OBERHOLSER. 



Following are notes ! on four species of North American birds 

 belonging to the families Phaethontidce, Ardeidce, and Charadriidce. 



Leptophaethon lepturus catesbyi (Brandt). 



Mr. G. M. Mathews has already indicated 2 that the name 

 Phaethon catesbyi Brandt should replace that of Phaethon americanus 

 Grant. The latter was originally based 3 on the bird from the 

 Bermuda Islands, and is, of course, the American representative 

 of Leptophcethon lepturus. It differs from Leptophcethon lepturus 

 in its somewhat smaller size and less extensive white tips on the five 

 outer primaries, the black areas on these feathers being therefore 

 larger. Mr. Mathews, like Mr. Grant, treats this form as a distinct 

 species, and for this course gives the following rather unconvincing 

 reason 4 : "This bird is only separable by its slightly larger [sic] 

 size and the variation in the black markings of the primaries. In 

 most genera such trifling differences would only be regarded as of 

 subspecific value, but when dealing with Ancient Forms, such as 

 the present, this must be given higher value." Examination of a 

 series of specimens shows, moreover, that the characters separating 

 Leptophcethon catesbyi from Leptophcethon lepturus are not entirely 

 constant, and that the form must, therefore, be regarded as a 

 subspecies of the latter. With this view of its relationship, its 

 name will become Leptophcethon lepturus catesbyi. 



1 For previous papers in this series, cf. 'The Auk,' XXXIV, April, 1917, pp. 191-196; 

 XXXIV, July, 1917, pp. 321-329; XXXIV, October, 1917, pp. 465-470; XXXV, January, 

 1918, pp. 62-65; XXXV, April, 1918, pp. 185-187; XXXV, October, 1918, pp. 463-467; 

 XXXVI, January, 1919, pp. 81-85; XXXVI, July, 1919, pp. 406-40S. 



2 The Auk, XXXII, No. 2, April, 1915, pp. 195-197. 



3 Phaeton americanus Grant, Bull. Brit. Ornith. Club, VII, No. XLX, December 26, 1897, 

 p. xxiv. 



4 Birds of Australia, IV, pt, 3, June 23, 1915, pp. 310-311. 



