CHAP. IV. FLIGHT OF BIRDS. 99 



hanging in the air in one place; his wings all the while 

 being briskly agitated: hence the common name of 

 wind-hover, given to it in some parts of England. Hen 

 harriers fly low over heaths or fields of corn, and beat 

 the ground regularly, like a pointer, or setting dog, 

 a fact also observed by Dr. Richardson in the harriers 

 of Arctic America, and which is in perfect unison with 

 their analogy to the swallows. Owls move in a buoyant 

 manner, as if lighter than the air, an effect in some 

 measure produced by the singular structure of their 

 wings. There is a peculiarity belonging to ravens, that 

 must draw the attention even of the most incurious : 

 they are often seen, when flying in company, as if 

 amusing themselves, by striking and cuffing each other 

 on the wing, in a kind of playful skirmish ; and, when 

 they move from one place to another, frequently turn 

 on their backs with a loud croak, and seem to be falling 

 to the ground. This singularity has been accounted 

 for on the supposition that they are then scratching 

 themselves with one foot, and thus lose the centre of 

 gravity. Woodpeckers, and some other birds, fly by 

 opening and closing their wings at every stroke ; and 

 so are always rising and falling in curves. Magpies 

 and jays are also slow flying birds, and make their way 

 something in the same manner. Pigeons and par- 

 ticularly the sort called smiters have a way of clashing 

 their wings, the one against the other, over their backs, 

 with a loud snap : another variety, called tumblers, re- 

 ceive this name from a habit they have of turning 

 themselves hi the air. The speed with which pigeons 

 fly, particularly those denominated, and sometimes used, 

 as carriers, is well known. An instance is recorded in 

 the Annual Register for 1?65, of one which travelled 

 no less than seventy-two miles in two hours and a half. 

 The whole of the humming-birds, although they fly 

 not to great distances at one time, yet glance through 

 the air with the velocity of a meteor ; and, probably, 

 for the time, fly swifter than any birds in creation. 

 From their small size, the eye cannot follow their course 

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