86 BULLETIN 113, UNITED STATES NATIONAL MUSEUM. 



troit) on the Great Lakes. In Europe from Great Britain south 

 to the Azores and Canary Islands, the Mediterranean, and the Black 

 Sea. 



Spring migration, — Early dates of arrival: Newfoundland, St. 

 Johns, March 1 ; Labrador, Eomaine, March 26, and Rigolet,' April 

 9. Late dates of departure : New York, Long Island, May 13 ; Mas- 

 sachusetts, Boston, May 25, and Woods Hole, June 10. Non- 

 breeding birds. linger on the coasts of New England late into or 

 all through the summer. 



Fall migration. — Early dates of arrival, excluding summer strag- 

 glers: Massachusetts, Woods Hole, September 24 (average October 

 8) ; Long Island, Orient, September 12 (average October 5). Late 

 dates of departures: Greenland, Gothaab, September 3; eastern 

 Labrador, November 2 ; Prince Edward Island, November 12 ; Nova 

 Scotia, Pictou, December 13. 



Casual records. — Accidental in Nebraska (Missouri River, May, 

 1871), Kerguelen Island (June 5, 1840), and Japan (Hakodadi). 



Egg dates.— Quebec, Labrador: Twenty records, May 25 to June 

 28 ; ten records, June 5 to 15. Nova Scotia : Fifteen records, May 15 

 to June 13 ; eight records, May 22 to 27. Great Britain : Eleven 

 records, April 28 to July 20; six records, May 20 to June 1. Ice- 

 land: Three records, May 18 and 28, and June 6. 



LARUS SCHISTISAGUS Stejneger. 

 SLATY-BACKED GULL. 



HABITS. 



Dr. Leonhard Stejneger (1885) has demonstrated, by an exhaustive 

 treatise on the subject, that this is a well-marked species, although 

 one can not read his remarks without realizing how much confusion 

 has arisen over the nomenclature and relationships of the Laridae. 

 In both size and color it is intermediate between the great black- 

 backed gull and the western gull; bu£ its best and most constant 

 character is the color pattern of the primaries, which Doctor Stejne- 

 ger has well described and illustrated. It is an Asiatic Species, with 

 its center of abundance in northeastern Siberia, which has established 

 a slight foothold on some of the islands of Bering Sea and in north- 

 ern Alaska, chiefly as a straggler. It may eventually become better 

 established in Alaska, as several other Asiatic species have done. 



Spring. — Doctor Stejneger (1885) first saw it on Bering Island, in 

 the Commander Islands, but afterwards found it common near Petro- 

 paulski, Kamchatka. Mr. N. G. Buxton's notes, published by Dr. 



