MOVEMENT IN BIRDS 



feet are enormously powerful, and well set back 

 on the body. With a singularly graceful curve 

 of head and neck, the cormorant dives without a 

 splash, appearing to slide into the deeps without 

 an effort. Beneath the water it moves with 

 marvellous celerity. It might well be thought 

 that a fish, in its native element, would readily 

 escape from the onslaught of a mere bird. But 

 if, by fortunate chance, a cormorant be seen in 

 the cr>^stal depths of the rock-pool, this belief 

 is dispelled for ever. The long, narrow, black 

 form appears sharpened to the finest point. 

 Propelled only by the backward sweep of the 

 webbed feet, turning like lightning to right and 

 left, around the angle of the rocks or about 

 the weeds, the black water-wolf pursues its quiver- 

 ing prey. In point of speed, the swiftest fish 

 appears to be hopelessly outmatched. In a few 

 seconds, the relentless bill overtakes it, and it 

 instantly disappears. 



The divers (Colymbidae) constitute a small 

 family of four species and one sub-species. Three 

 of these^the great northern, the red-throated, 

 and black-throated divers — are British. An 

 examination of the structural peculiarities of these 

 birds shows them to be wonderfully adapted for 

 sub-aquatic movement. Divers they are es- 

 sentially, every line of their graceful yet powerful 

 forms being drawn with the view of swift pro- 

 gression beneath the water. The legs set far 

 back, are broad, yet perfectly flat, and when the 

 webbed feet are drawn up preparatory to the 

 stroke, the narrow edge alone of leg and foot is 

 opposed to the element. As the foot descends 

 these broad surfaces are brought to bear upon the 

 water, and the bird shoots forward like an arrow 

 driven from a bow. 



49 



