86 THE WINGS. 



wing, weighs more than all the other muscles of its 

 body put together, constituting not less than one- 

 sixth part of the weight of the whole body; whereas, 

 those of the human body are not one-hundredth part 

 as large in proportion. 



Some birds have to seek their food on the wing, 

 consisting of such very small insects that many 

 hundred must be swallowed for a meal, and in 

 these we accordingly find a spread and power of 

 wing truly astonishing. "We cannot take a better 

 example than our common Swift, the largest of our 

 Swallow tribe, whose well-known scream and rapid 

 flight must be familiar to every one. It has to seek 

 its livelihood solely in the air, on insects so small 

 that we can with difficulty perceive them, even if 

 slowly passing before our eyes. It could not there- 

 fore live a day, unless gifted with extraordinary 

 powers of flight ; it must not only be able to move 

 rapidly forward in a straight line, but also be able to 

 turn, as quick as thought, to the right or left, up- 

 wards or downwards, to catch its minute prey. And 

 such is the case; the bird is so light that it weighs 

 little more than an ounce, and yet the spread of its 

 wings, from tip to tip, is not less than eighteen 

 inches. But extraordinary as these proportions are, 

 in length of wing, compared with weight, in this 

 our British species, they are exceeded in a newly- 

 discovered species in the East Indies, called the 

 Javanese Crested Swallow*, whose uncommon 

 length of wing indicates a speed far beyond that 

 of our Swift. Other birds, again, there are, which 

 require additional powers, not in the air, but under 



* Macropteryx longipennis. 



