184 BULLETIN 113, UNITED STATES NATIONAL MUSEUM. 



so that the snow melted in the hot sun, and on this and the following days 

 geese, swan, ducks, gulls (Larus vegae and (?) L. glaucescens) , and waders 

 (especially Trihga maculata, T, subarquata, T. sakhalina, Phalaropus fuli- 

 carius, and Charadrius fulvus) migrated in great numbers. At last, on May 

 30, it rained, while the thermometer varied between 16° eels, above zero and 

 as much below ; snow became scanty on the open places, and the first rosy gull 

 was reported. On the morning of May 31 one of my men saw a pair, and 

 during the day I went on the river, where the fathom-thick' ice was still quite 

 safe, and came across several dozens. The sun was shining brightly, and in 

 the distance each pair appeared like so many roseate points on the bluish ice 

 of the great stream. I say " pair," as from their first arrival the birds were 

 constantly seen in pairs. They had evidently just finished their migration and 

 were tired after their exertions, for they sat very quietly on the ice, and though 

 all attempts to stalk them were unavailing, they would not fly far, but only 

 shifted from place to place with a lazy and somewhat uneasy motion of their 

 wings, which made me jot down in my notebook on the spur of the moment 

 that the flight was more fulmar-like than gull-like. 



Courtship. — Although most of the birds seemed to be paired on 

 their arrival, he noted some squabbles with unmated males and the 

 following courtship performance: 



Every now and then the male tried to express his feelings to his mate by 

 pecking her curiously, as if trying to kiss her, with his open beak on her head 

 or neck, or made a" few steps round her to one side or the other, showing off 

 as some pigeons do ; then with a sound like trrrrrr lowered his neck and breast 

 to the ground, and in this position, with all the hinder part of the body, the tall, 

 and the ends of the folded wings high up in the air, continued for some seconds 

 his little promenade before the female, who very rarely engaged in such antics. 



Nesting. — He 



found the rosy gull nesting in little colonies of from 2 or 3 to 10 or 15 

 pairs, in company with the common black-capped tern of the delta, which, 

 however, in nearly every case exceeds it in numbers. A pair or two of 

 Totanus fuscus nearly always breed with them, and not unfrequently 

 Colymbus arcticus and Fuligula gladaXis, sometimes accompanied by the white- 

 winged gull (Larus Glaucescens), and a pair or two of Squatarola helvetica. 

 A little low island in a lake is usually selected for the breeding place, and 

 this made the nests very difficult of access, as until the last days of June a 

 boat can only be used near the banks and must be then dragged over the ice, 

 which is exceedingly slippery and generally unsafe after June comes in, espe- 

 cially near the islands, as I found to my cost. One of the colonies, however, 

 was on a piece of wet tundra near two lakes, a square kilometer In extent, 

 covered with a labyrinth of pools of snow water from 2 to 6 or even 10 inches 

 deep, but practicable in wading boots, thanks to its floor of everlasting ice 

 beneath the underlying mud. Between these pools, which were from 15 to 50 

 feet in diameter, were pieces of very wet ground covered with Carices, damp 

 mossy spots, and even tiny patches of comparatively dry bog covered with 

 lichens or Betula nana. 



In this colony I found 10 nests of Rhodostethia, placed, among those of the 

 tern, on little mossy swamps almost bare of grass, evidently because the more 

 grassy places were too wet and unsafe. But in the remaining colonies the state 

 of affairs was otherwise; there the tern nested on the moss (sometimes making 

 no nest at all), and laid its one or two eggs much nearer to the dry parts of 



