LIFE HISTORIES OF NORTH AMERICAN GULLS AND TERNS. 183 

 RHODOSTETHIA ROSEA (Macffillivray). 

 SOSS'S GULL. 

 HABITS. 



The rosy gull is not only the most beautiful of the gulls but it is 

 the most strictly Arctic, one of the rarest in collections and, to all 

 but a favored few, the least known. Owing to its restricted habitat 

 in an inaccessible region, few of us may ever expect to see it. As its 

 wanderings carry it over a wide area in Arctic regions, a few speci- 

 mens have been picked up by Arctic explorers. For nearly all that 

 we know of its habits we are indebted to the Russian explorer and 

 good ornithologist, Dr. Sergius A. Buturlin (1906), who, during his 

 visit to the Kolyma delta, on the Arctic coast of eastern Siberia, in 

 1905, collected 38 skins and 36 eggs of this beautiful bird. Fortu- 

 nately he has given us a very full and interesting life history of this 

 species, from which I shall quote freely. 



The delta of the Kolyma, which is the easternmost of the great rivers of the 

 North Polar basin, lies, roughly speaking, between 68J° and 69|° N. lat. and 

 from 159° to 161J°.E. long. This vast area, at least 15,000 square kilometers 

 in extent, consists of a liberal admixture of lakes, lagoons, channels, rivulets 

 ("viska"), swamps, moors, and damp ground of every description, with dry 

 places only at intervals. The southern part of this delta, some one-third or 

 even less of the whole, is covered by forests. The other parts stretch beyond 

 the northern limit of the forests, but are for the most part covered by ex- 

 tremely dense and well-grown bushes of Alnus incana (ordinarily 5 to 10 feet 

 high, but occasionally reaching a height of 15 feet with a thickness of from 

 5 to 6 inches), and by various species of Salix. The traveler must go some 

 20 kilometers from the main channels of the great river, and then perhaps 2 

 or 3 kilometers from the rivulet or " viska " along whieh he is advancing, to 

 find a little piece of true " tundra " such as I have seen on Kolguev Island, 

 with lichens covering the ground, tiny bushes of Betula nana, and different 

 Salices studded over the drier spots, and mosses and Cariees clothing the damp 

 portions. 



Spring. — After a period of very cold weather during the first half 

 of May he describes the breaking up of winter, the coming of the 

 earliest birds, and the arrival of the Ross's gulls on their breeding 

 grounds, as follows: 



Toward the middle of May the weather became somewhat better, and the 

 snow melted at midday (freezing again, of course, in the shade), so that on 

 the southern slopes and sandy islands the soil made its appearance. At this 

 time the first specimens of geese (Anser serrirostris, A. garribeli, and in small 

 numbers A. rhodorhynchus) , and even swans (Cygnus bewicki) made their 

 appearance, migrating down the river ; while about May 20 small parties of 

 them passes!. Linota exilipes, Plectrophenax nivalis, Gorvus orientalis, the 

 white-tailed eagle, and Lagopus albus (partly wintering in the district) had 

 of course long been present. Then migration stopped, and snowstorms began 

 again until. May 27. That day was fine, with only some 3°-6° eels, of frost, 

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