BIRDS OF ICELAND 121 



Stercorarius crepidatus (Gmel.). 

 Kichardson's Skua. 



Native name : ' Kjoi ' (partim). 



A summer visitor in considerable numbers, from the 

 end of April to mid- September, breeding (singly, not 

 in colonies, like the last two species) here and there, 

 not only near the sea, but far into the interior — 

 wherever, in fact, other birds are sufficiently numerous 

 for it to find a livelihood by robbing them of their eggs 

 and young. 



The nest is generally situated in a little hollow on 

 high ground ; it consists of a small depression in the 

 turf or lichen large enough to contain the two eggs ; 

 occasionally it is on the top of a little mound if the 

 hollow be a damp one. The eggs are very like normal 

 examples of those of the Brown-headed Gull (Larus 

 ridihunclus) ; they are olive brown in colour, spotted 

 and blotched with dark brown, and 2 J inches long. 



There are two varieties of this species — what are 

 known as the ' light ' and ' dark ' forms — and in Iceland 

 they are about equally common. A breeding pair may 

 consist of one light and one dark bird, two light or two 

 dark ones. The dark form is sooty brown all over, 

 rather darker on crown, wings, and tail. The light 

 form has light underparts with a quite white breast, 

 and a light yellow patch of hackle-shaped feathers on 

 the side of the head (this is indistinctly indicated in 

 the dark form also). There are also intermediate 



