222 ORNITHOLOGICAL EXPLORATIONS. 



known to breed in the interior, e. g., in the Kamennij Valley. But siiice 

 the introduction of the two kinds of Muridce^ Mus musculus and Arvicola 

 rutila, especially the latter (see my " Contributions," &c., Pr. U. S. Nat. 

 Mus., 1883, p. 88), with which the whole island now is literally swarming, 

 the numbers of the owl have been gradually increasing, so that during 

 the winter of 1882-'83 they were very common and a conspicuous feature 

 in the landscape. 1 know of at least twenty-four individuals that were 

 killed in the neighborhood of the village, and still they were as numer- 

 ous at the end of the winter as when the cold weather set in. They 

 made their first appearance on the hill round the village about the mid- 

 dle of November, and from that time they were a common sight on the 

 pointed tops of the sand-dunes or among the hummocks of the tundra, 

 hunting Arvicola in broad sunlight. A specification of the contents of 

 the stomachs examined by me is given below. The birds themselves 

 were excessively fat, caused by the rich and easy supply of food, their 

 entrails being firmly wrapped up in a mass of tallow, while the whole 

 body was covered with a thick layer of firm and whitish fat. 



They remained in the neighborhood of the village until the beginning 

 of May, on the 2d day of which three individuals were still to be seen. 

 Most of them then retired to the higher mountains in the interior of the 

 southern part, but a few pair bred not far from the sea shore. Thus, 

 for instance, a pair was seen during the whole summer in the neighbor- 

 hood of the great seal rookery ; and on the 3d of September, 1883, a 

 family of five individuals had taken posts close to the road between the 

 rookery and the village. 



On Copper Island, where they only occur occasionally during the cold 

 season, they were as rare during the winter 1882-'83 as ever. On that 

 island no mice are found. 



From the above it would seem as if the increase of the Arvicola has 

 been the direct cause of the increase of the owl, consequently, that the. 

 " increase in the procreative powers is owing to the abundant supply of 

 food," and that it is not " to be traced rather to the cause (whatever it 

 be) which renders the small rodents in that very year so much more pro- 

 lific than common" (Collett, Orn. Eem., Vid. Selsk. Forh. Christiania, 

 1872, p. 224, Extr., p. 38; Id., Nyt. Mag. Natur., 1877, p. 169). I may 

 add here that none, even the oldest, of the residents can remember 

 ever to have seen the snowy owl so plentiful as it occurred last winter. 



The specimens are all rather heavily barred, even the lightest male 

 l^eing very much so, 



