The terrestrial mammals and birds of North-East Greenland. 23 



The latter will be entirely or partly ruined on the large, snowless 

 distances, and only on localities which are at the same time provi- 

 ded with a thick layer of snow which has drifted together, and 

 sufficiently rich vegetation, it will be able to sustain life. The few 

 signs of lemming life which my investigations in the spring 1907 

 brought me, were thus bound exclusively to localities fulfilling those 

 two conditions; but such places were very rare and must be sought 

 especially on mountain slopes and in hollows on the top of the 

 mountain itself. On the richly grown meadows and plains, as for 

 instance the plain between Hvalrosodden and Rypetjeldet, where the 

 lemming had appeared especially numerous in the preceding after- 

 summer the ground was almost perfectly free from snow all winter, 

 and even if a small spot of snow was to be found here and there, 

 the layer of snow on such places was far from sufficiently thick to 

 render the animal the necessary protection against the severe cold. 



— My not few attempts of excavation in the summer 1907 were 

 positively all in vain. I only found empty lemming burrows and 

 deserted nests even in places where, in consequence of former ex- 

 periences, I might expect to meet with a particularly rich lemming 

 life. Indirect proofs of this strikingly great reduction of the lem- 

 ming stock were rendered most conspicuously through the before 

 mentioned enemies of the lemming. Already in the early spring 

 foxes and ravens sought other means of livelihood and were seen 

 most frequently along the coast or on the ice, trying by the open 

 holes and crevices to seize upon the here occurring lower animals. 

 In quite exceptional cases I saw a fox in pursuit of lemmings. 

 Snowy owls and falcons sparingly appeared on the passage, and the 

 skua, the breeding conditions of which depend completely in these 

 regions on a tolerably normal lemming life, did not breed at all 

 this summer. 



The great multitude of lemmings presented by the after-summer 

 1906, might seem to indicate that several successive favourable years 

 have gone before and that winters like that in 1906 — 07, are rather 

 unfrequent. 



In the summer 1908 I might again meet with the lemming in 

 most of the tracts which I examined, but nowhere in anything 

 like the number which was seen in 1906. As far as I was able to 

 observe, the lemmings multiply very strongly under normal condi- 

 tions. For this reason it seems most likely that ihe increase of 

 individuals after an unfavourable year like 1907 is effected chiefly 

 through the brood of the surviving, stationary animals, even if also 



— what much might seem to indicate ^, an immigration takes place 

 1 See the article about Mgodes torqvatus — the traces on the ice. 



