240 



O R D E R IX. 

 CHELIDONES. 



THE SWALLOW TRIBE. 



THESE are a particular class of the insect-eating birds, 

 which agree in so many characters, that they form a con- 

 venient group. They prey upon insects only; they capture 

 them chiefly while on the wing, and their whole structure 

 and manners are in accordance with that mode of feeding. 

 Thus they are all summer visitants in Britain, because there 

 are not so many insects to be caught in the winter as could 

 support even the thousandth part of them. Again, their 

 wings are very strong and long, and their tails produced in 

 forky points, so that they can remain the whole day on the 

 wing, and wheel round with very little diminution of their 

 velocity. Their plumage also is exceedingly firm, so that the 

 wind neither takes hold of, nor is apt to ruffle it. Their form 

 is that which has been found to make the fastest sailing- 

 vessel, full forwards, and lengthened and tapering back- 

 wards. They have small and weak feet, as they use those 

 little, and they would be a weight to carry in flying ; but the 

 feet and the stiff points of the tail, and even the edges of 

 the wings, are so formed, that they can cling to an upright 

 surface, or even to an overhanging one, if there be roughness 

 to hold their little claws. Their sight is exceedingly acute, 

 so that they probably see small flies at a greater distance 

 than man can discern them. Their bills are flat, very wide 



