THE MUSEUM. 



55 



'Other water birds, sometimes higher, 

 sometimes lower than the other spec- 

 ies, sometimes in the midst of them 

 according to where the holes and 

 cracks in the rocks are situated. The 

 nest-holes are found in the rocks and 

 I never saw a single pair breeding in a 

 hole dug out of the soft ground as is 

 usually the case with other Puffins. 



Glaucous-winged Gull, Larus f^lau- 

 ccsccus. 

 This species breeds on the various 

 islands but most numerous all along 

 the shore of Copper island. The im- 

 mense colonies are quite frequently 

 on inaccessible rocks overlooking the 

 sea. Eggs were found as early as 

 May 1 6th and measure 73x54 ;//;//. 

 Compared with the eggs of the Glau- 

 caus Gull, Larus g/aiiciis, those col- 

 lected by me show a just perceptibly 

 more greenish tinge and somewhat 

 smaller, more numerous and better de- 

 fined spots. 



Slatv-backed Gull, Larus scJiistis- 

 gus. . 

 Not found on the islands to any 

 great extent. On the 20th of April I 

 observed them for the first time in 

 company with the Glaucaus Gulls on 

 the eastern shore of Bering Island. 

 From the inhabitants I learned that 

 this bird breeds at Babuschkin Kamen 

 in the bay of Avatscha, and on Starit- 

 skof island, south of the entrance to 

 that bay. 



Pacific Kittiwake, Riss atridactyla 

 pollicaris. 

 This is a common breeding bird on 

 the islands but as all places do not 

 suit this noisy bird, the rookeries are 

 comparatively few, a compensation 

 ■for which is found in astonishing num- 



ber of individuals inhabiting each rook- 

 ery. For such are chosen steep walls, 

 rising perpendicularly out of the deep 

 sea, and especially high pinnacles 

 standing lonely, amidst the foaming 

 breakers, provided they are fitted out 

 with shelves and projections upon 

 which to place the nests. As Copper 

 island offers such localities all around 

 its shore, the Pacific Kittiwake is pret- 

 ty well distributed all over that island. 

 They arrive about the first of April 

 and I found the first young hatched 

 on August 2nd. 



Red-leg Kittiwake, Rissa brevir- 

 ostris. 

 This species is in every respect, 

 both structurally and in its habits, a 

 true Rissa. Like its black-legged 

 cousin, it only selects steep and inac- 

 cessible rocks, and in none of its hab- 

 its at the breeding place could I de- 

 tect any marked difference. They ar- 

 rive at the islands about the same 

 time, hatching their young simultan- 

 eously with the other species. Those 

 birds not engaged in breeding do not 

 seem to straggle around to such an 

 extent, as do the black-legged ones. 

 The two species usually keep apart 

 from each other but in one place I 

 found them breeding together, on a 

 rocky wall, the black-feet however al- 

 ways higher up than the present spec- 

 ies. The two kinds were easily dis- 

 tinguished even on the nests, brcvi- 

 rostris having the gray of the mantle 

 of a perceptibly darker shade than pol- 

 licaris. 



Parasitic J.eger, Stcrcorarius par- 

 asiticus. 

 On the islands the dark form is the 

 most common. A few only with low- 



