The terrestrial mammals and birds of North-East Greenland. 175 



During the beginning of June the Skuas distributed themselves 

 over their old nesting-places and they fed again essentially on Lem- 

 mings, which certainly were not nearly so common as in the autumn 

 of 1906 appearing however so frequently upon the whole of the 

 territory, that the Skuas did not hesitate to breed. The laying took 

 place at the end of June (the first nest containing a fresh-laid egg 

 dates from June 18'i^) and in the next days very many Skuas-nests 

 were found everywhere in the Stormkap territorry, at Hvalrosodden 

 and in the neighbourhood of the ship's-harbour. 



In other words this summer the breeding-conditions were quite 

 normal. Later in the summer numerous immature birds appeared 

 just as in 1906; their behaviour corresponded exactly with what 

 I had noticed earlier. 



This Skua prefers as breeding-ground stony, sparsely covered 

 plains. But here the birds absolutely require a small bog, a fresh- 

 water pond or an overflow of melted snow near the nest. 



The distance from the nearest salt-water may differ a good deal; 

 nests were found 30 km. from the shore. 



The nest is a shallow hollow in the ground, natural or scraped 

 by the bird, and sparsely lined with some few withered straws and 

 a single leaf or two of Salix ardica. 



Mr. Herluf Winge in his "Grønlands Fugle" page 210 says 

 regarding this species that "it breeds socially and is according to 

 Holbøll nearly always seen in flocks". 



In N. E. Greenland quite the reverse is the case. 



In 1908 some 40 Skua-couples nested in the Stormkap region,, 

 where so many Lemmings lived. The nests were evenly distributed 

 all over the territory, so that every couple became posessor of a 

 certain hunting-district the outlines of which were drawn with a 

 certain — almost geometrical — accuracy; inside these limits no 

 stranger would be tolerated. 



Similar conditions, though not quite so conspicuous, were found 

 on all other places where I had the opportunity of watching nesting 

 Skuas. 



The majority of the Skuas-nests found in 1908 contained 

 two eggs. 



Between the laying of the P* and 2"^ eggs as much as 50 hours 

 may elapse ; the rule however is 36 to 48 hours. Later on I observed, 

 that the young ones emerged with a corresponding difference in time. 



The normal time of incubation is 23 days. 



The eggs are extremely variable in shape, size and colour. 

 Several types were, with respect to the structure and colour of the 

 shell as well as to the shape and size of the eggs, so similar to 



