BUFFON'S OR LONGTAILED-SKUA 225 



the sea procure all the food necessary for their own support and that 

 of their young entirely by their own exertions. But at other times, 

 and especially on migration, they seem to subsist almost entirely on 

 food disgorged by the Terns and the smaller Gulls. Gillett noticed 

 that every flock of kittiwakes near Novaya Zemlya was attended by 

 numbers of this species and Richardson's skua, which kept swooping 

 at them like hawks and forcing them to disgorge their prey. 1 Booth 

 was once engaged in watching a pair of adult birds amongst large 

 numbers of kittiwakes, which evidently did not appreciate their society, 

 making rapidly off when approached, though no attack was offered. 

 When at last a small flock of terns came flapping quietly down the firth, 

 the skuas were at once off in pursuit, with sharp and piercing cries. 

 These birds were evidently on their way to their breeding-grounds 

 at the beginning of June, and Booth was able to see something of their 

 courting display, and notes that an immense amount of swimming 

 round, bowing, and chattering was indulged in by them in the 

 water. 



In North-east Greenland, A. L. V. Manniche records the first pair 

 as arriving on May 28. This is rather before the average date, and 

 most birds reach their breeding-places in this district about the first 

 week in June. In Lapland and Northern Scandinavia they must 

 naturally arrive earlier, as the first eggs may be found at the beginning 

 of June, and Manniche noticed that an interval of about three weeks 

 elapsed between the arrival of the first pair and the discovery of the 

 first egg in Greenland. 



As already noted, the skuas arrive in pairs and immediately take 

 possession of their breeding territory. They breed to some extent in 

 colonies, but the nests are never placed close together. Each pair 

 has its own district, and within these bounds the presence of no 

 stranger is tolerated. One bird is always on the watch to drive away 

 intruders. As far back as 1862, Wolley's collectors found that this 

 species bred in extraordinary numbers during lemming years, and in 



1 Ibis, 1870, p. 307. 



