2288 PLOVERS, SANDPIPERS, SNIPE, JACJLNAS, GULLS 



tear their prey in pieces, while holding it under their crooked talons. They rarely 

 take the trouble to fish for themselves, but, watching the smaller gulls and 

 terns while thus employed, they no sooner observe one to have been successful than 

 they immediately give chase, pursuing it with fury; and having obliged it from 

 fright to disgorge the recently-swallowed fish they descend to catch it, being fre- 

 quently so rapid and certain in their movements and aim as to seize their prize 

 before it reaches the water. ' ' Of the two members of the group breeding within 

 the limits of the British Islands, the largest is the great skua (S. catarrhades) , its 

 only resort within those limits being the Shetlands. 



Measuring upward of twenty-four inches in length, the great skua has the two 

 central tail feathers less than an inch longer than the others, and may be further 

 distinguished by the white bases to the flight feathers, the general color being dark 

 brown. It nests in a hole of about a foot in diameter, laying one or two eggs 

 on a lining of moss and heather. It is to this species that the two southern 

 forms alluded to above are allied. Taking the other species in their order of size, 

 the long-tailed skua (S. parasiticus) , which measures twenty-two inches in length, 

 has the two central tail feathers upward of nine inches longer than the rest. Es- 

 sentially an Arctic species, this bird is but a very occasional visitor to the British 

 Islands. The pomatorhine skua (S, pomatorhinus) , on the other hand, is a regular 

 winter visitor to the last-named area; it may be distinguished by the two central 

 tail feathers being twisted upward and exceeding the others in length by four 

 inches, the total length of the bird being twenty-one inches. Lastly, we have 

 Richardson's skua (S. crepidatus} , measuring an inch less than the last, and distin- 

 guished by the two central tail feathers being only three inches longer than the 

 others. Circumpolar and subarctic in its breeding range, this species is much more 

 abundant in Britain than either of the others, nesting not only in the Hebrides, 

 Orkneys, and Shetlands, but likewise on the mainland in the counties of Caithness 

 and Sutherland. 



