248 THE HAUNTS OF LIFE 



see a marvellous thing, but the marvel in- 

 creases when in front of us the bird tilts its 

 body and turns, and comes towards us down 

 the other side of the ship, and all, so far as 

 we can see, without a stroke of its wings. This 

 sailing is, we think, the most wonderful loco- 

 motion in the world, and the puzzle of it does 

 not seem to have been altogether solved. It is 

 finely illustrated by vultures "soaring" in 

 mid-air, describing circle after circle, ascend- 

 ing in a magnificent spiral and sailing down 

 again, and all, so far as the field-glass shows, 

 without any stroke of the wings. The word 

 "soaring" is often applied to this mysterious 

 kind of flight, but "sailing" is a better word. 

 It is better to keep "soaring" for the ascend- 

 ing flight of the lark, where there is very 

 rapid up-and-down movement of the wings, 

 without any backward stroke. This leads on 

 to the "hovering" of the kestrel, where the 

 up-and-down movements of the wings are 

 extraordinarily rapid, and to the "fluttering" 

 of a humming-bird, poised like a moth before 

 a flower. But sailing is a different matter. 



Sailing is seen in birds with a large wing- 

 area or sail-area in proportion to the size and 

 weight of the rest of the body, e.g. albatross, 



