RICHARDSON'S SKUA. 355 



very active, and in the Varanger fjord I have seen them sailing round and 

 round at all hours. The nest is placed on the wide open moor with no 

 cover of any kind, and is a mere depression in the ground scantily lined 

 with a little dry grass and occasionally a few dead leaves. Two is the 

 normal number of eggs, but sometimes birds have been found sitting on a 

 solitary egg, and in rare instances three eggs have been found in the same 

 nest. Few eggs vary more in shape than those of Richardson's Skua, 

 some being very long and pointed, others almost round. They vary in 

 ground-colour from russet-brown to pale olive ; the overlying spots are dark 

 brown, sometimes almost black, generally evenly though somewhat spar- 

 ingly distributed over the entire surface, but occasionally most of them 

 are collected in a ring round the larger end, where they are sometimes 

 confluent ; the shape of the spots is very fantastic, many of them are pro- 

 longed into streaks, and they vary in size from that of a large pea down- 

 wards ; the underlying spots are few, very inconspicuous, and pale greyish 

 brown in colour. The eggs vary in length from 2*55 to 2'0 inch, and 

 in breadth from 1'7 to 1*55 inch. It is almost impossible to give any 

 character by which the eggs of this bird may be distinguished from 

 certain varieties of those of the Common Gull, Black-headed Gull, and 

 Pomarine Skua. 



The note of Richardson's Skua at the nest resembles the syllables kyow ; 

 but as it screams whilst pursuing the small Gulls and the Terns it may be 

 likened to the sound of yah, yah. 



Dark forms of this species may be found paired with light forms ; but 

 the progeny, when adult, always resemble one of their parents in colour, 

 though immature examples are sometimes mistaken for intermediate forms. 



Richardson's Skua and Buffon's Skua may be distinguished from the 

 Great Skua and the Pomarine Skua by their smaller size and narrow 

 pointed central tail-feathers, but they appear to intergrade with each other 

 so closely that some ornithologists doubt whether they are more than sub- 

 specifically distinct*. Richardson's Skua varies in length of wing from 



* Howard Saunders, who is supposed to have studied the Gulls, Terns, and Skuas more 

 than any other ornithologist, and has promised us a monograph of the Laridae when his 

 studies are more advanced, writes, in the fourth edition of ' Yarrell's British Birds,' iii. 

 p. 684, " An unfailing distinction at all ages is to be found in the colour of the shafts of 

 the primaries;" and then he proceeds to explain that in Eichardson's Skua they are all 

 white, whilst in Button's Skua only the shafts of the two outer ones" in each wing are 

 white, the others having dusky shafts. Baird, Brewer, and Ridgway deny the validity of 

 this character, and assert that in the number of primaries having white shafts the two 

 species completely iutergrade ; but Saunders admits that the passage on page 678 of the 

 work referred to, in which he describes the colour of the shafts of the primaries of 

 Richardson's Skua as white only on the first and second, is an error. Dr. Stejneger has, 

 however, pointed out that the position of the nostrils varies in the two species. In 

 Buffon's Skua they are said to be nearer the frontal feathers than the tip of the bill, whilst 

 in Richardson's Skua the contrary is said to be the case. 



