00 THE WINGS. 



of the Swift's wing. Sometimes, by carefully watch- 

 ing these birds in clear water, opportunities occur 

 of observing their progress beneath the surface, 

 when they may be seen flapping with their short 

 wings, as if flying, thus acquiring a much greater 

 speed than they could by the use of their webbed 

 feet alone. 



There is one bird, however, the "Water Crow 

 (Turdus cinctus\ in size, shape, and wings very 

 similar to the Blackbird, which also dives; but as it 

 does not pursue fish, living on spawn, or such sort of 

 food as may be collected without effort, the diver's 

 form of wing is not necessary, and accordingly the 

 only use of its wing, under water, is, by flapping or 

 jerking it upwards, to prevent its rising; for as, like 

 all other birds, it is much lighter than water, it 

 must of course use some power to keep itself beneath 

 the surface, and this it does by means of its wings. 

 These birds are chiefly found in wild parts of the 

 country, abounding in streams rushing over rocky 

 beds. There they may be seen perched upon a 

 stone on the edge or middle of the water, from 

 whence they wade beyond their depth, and continue 

 their course along the bottom, where they may be 

 observed struggling to preserve a footing, and pre- 

 vent themselves from rising, by a strange tumbling 

 sort of motion of their bodies, accompanied by 

 quiverings of their wings, which, acting upon the 

 water above, helps to keep them down. 



Before we proceed to speak of migration, or that 

 instinct which induces birds to visit and retire from 

 certain countries at particular times of the year, it 

 is necessary to say a little on the . speed with which 



