BIRDS OF THE SEA 457 



and then the dark shiny bulk of a porpoise is seen 

 revolving through the water, giving the casual 

 observer the impression that he is constructed on 

 the principle of a cart-wheel. If one sees him in 

 a fathom or more of clear water, however, this 

 view changes in a flash ; his long black form is 

 straight as an arrow as he darts hither and thither 

 in restless quest. 



Above the shoal a group of sea-birds are hover- 

 ing, their white wings now and again flashing in 

 the sunlight. As one watches closely the light 

 airy forms of the little Arctic Terns can be easily 

 distinguished from the more steadily balanced and 

 slower winged Lesser Black-backed and Herring 

 Gulls which are eagerly scanning the water in their 

 wheeling flight. The Terns drop swiftly to the 

 sea when they sight their quarry, and then rise 

 instantly, fluttering upwards, leaving a dimpling 

 ring behind. The heavier Gulls swoop downwards 

 and often alight and float upon the surface before 

 attempting to regain the air. Then come fishers 

 bolder and more impetuous than any of these. 

 Sailing widely on their broad pinions the Gannets 

 appear. From great heights they hurl themselves 

 sheer into the water, the spray leaping upwards as 

 though from a falling stone; then they follow their 

 prey far in the deeps, often remaining for several 

 minutes beneath the surface. The herring owes 

 its immunity from destruction to sheer force of 

 numbers. When the shoal is beneath the surface, 

 the porpoise and other hungry sea-dwellers are 

 taking their toll ; W'hen it ascends and hisses along 

 the face of the water, the opportunity of a myriad 



