258 THE BIRDS OF THE BRITISH ISLES. 



sharper and more ferocious when the bird is engaged in 

 piracy. 



The Arctic Skua is a moorland nester ; its colonies are 

 scattered, nests being seldom near together. The nest (Plate 113) 

 is little more than a hollow scraped or flattened in the grass 

 or heather, and has very little, if any, lining. The eggs 

 (Plate 116), laid at the end of May or in June, are usually two 

 in number, and are dark or light olive-green or brown in ground, 

 blotched and suffused with darker brown and underlying grey. 

 An invader on the moor may be attacked and struck, usually 

 with the feet, but sham disablement is a trick of the bird to lure 

 the visitor from the vicinity of the nest ; as the seemingly 

 damaged bird struggles along the ground it beats with the 

 extended wing, exhibiting the white shafts. The nestling is 

 greyish brown, and shows little indication of the phase into 

 which it will develop. 



The dark phase is dark brown, with a distinct slate tinge in 

 many examples, darkest on the head and paler beneath, but 

 often showing yellow on the ear-coverts. The light birds have 

 the neck and under parts white, often with a creamy or pale 

 brown band across the breast, and at times with all the white 

 suffused with cream ; one of the most beautiful birds I have 

 seen was slate-brown above, and rich chocolate beneath. Light 

 birds may have the back of the neck suffused or streaked with 

 yellow. Immature birds of either form are barred and streaked 

 with brown and reddish buff, and the barring is most noticeable 

 on the lower back. The bill and legs of young birds are 

 brownish black, in old birds black with the cere bluish. The 

 irides are dark brown. Length, 23 ins. Wing, 13 ins. Tarsus, 

 i'4 ins. 



Buffon's Skua. Stercorarius longicaudus Vieill. 



Buffon's vSkua (Plate 115) has a more Arctic circumpolar 

 range than the last species, and in winter is not met with far 



