76 BULLETIN 113, UNITED STATES NATIONAL, MUSEUM. 



Spring migration. — Long Island, Rockaway Beach, March 8; 

 Maine, Portland, April 27. 



Fall migration. — Gulf of Cumberland, September 27; Prince Ed- 

 ward Island, October 7 ; Bay of Fundy, November 1. 



LARUS NELSONI Henshaw. 

 NELSON'S GULL. 



HABITS. 



This large gray-winged gull of the Pacific coast and Bering Sea is 

 so rare that its status, as a species, is none too well established, 

 though the four specimens which had been studied by Doctor Dwight 

 (1906) led him to the conclusion that ^^nelsoni seems to have as good 

 a claim for specific distinctness as does ku?nlieni, of which it appears 

 to be a large edition." Nothing seems to be known about its breed- 

 ing habits or its breeding range. 



Plumages. — Doctor Dwight (1906) after examining the scanty 

 m.aterial available, suggests the following, regarding the probable 

 plumage changes of this rare species : 



The young bird has never been described, but inasmuch as kumlieni in juvenal 

 plumage is scarcely to be distinguished from glaucescens, there is every reason 

 for expecting the corresponding plumage of nelsoni to be practically the same. 

 The birds, though, ought to be larger than glaucescens, and I have no doubt that 

 very large specimens novs^ labeled " glaucescens " in various collections will 

 eventually prove to be nelsoni. Such a bird has been recorded in the British 

 Museum Catalogue, but somehow I overlooked it when examining the collection. 

 In the American Museum, however, I find two specimens (Nos. 26234 and 61536) 

 so much larger than glaucescens usually is that I believe them to be nelsoni. 

 The tarsi and feet are unusually large and massive and the bills very heavy. 

 The bird in the Philadelphia Academy is completing an adult post-nuptial moult, 

 but the other specimens throw very little light on the subject of moult in this 

 species. 



I have never recognized the bird in life and can not find anything 

 in print regarding its habits, in which it probably closely resembles 

 Kumlien's and the glaucous-winged gulls. Some day, when its breed- 

 ing grounds are discovered, we may know more about it. I am in- 

 clined to think that it may prove to be identical with Larus kum- 

 lieni., or at best only subspecifically distinct from it. The fact that 

 a young gull, possibly referable to kumlieni., has been taken on the 

 coast of California adds weight to this theory, which may be estab- 

 lished when more material has been collected. 



DISTRIBUTION. 



Range. — Three specimens taken in Alaska — St. Michael, June 20 ; 

 near Bering Strait ; and Point Barrow, September 5. One taken in 

 Lower California, San Geronimo Island, March 18. One taken in 



