()18 CYPSELUS MURARIUS. 



to see the Swifts wheeling joyously over the town at a consider- 

 able height. How the insects, of which of course they were in 

 pursuit, could exist in such a rain is not less astonishing. In 

 dry and sunny weather, however, it generally rests in the mid- 

 dle of the day, and towards evening is extremely active, filling 

 the air with its shrill and joyous screams. 



Its food consists entirely of insects, which it seizes exclu- 

 sively on wing. Several curious circumstances may be noted 

 with reference to its pursuit of these animals. In rainy or 

 damp coldish weather, the Swifts are to be found flying at 

 no great height, generally from ten to fifty or sixty yards, fre- 

 quently in bands of twenty or more, often shooting along the 

 sides of the hedges, descending in curves, and skimming the 

 surface of the grass, wheeling and circling, now and then turn- 

 ing abruptly on spying an insect out of their course, and per- 

 forming all sorts of evolutions, scarcely describable, however, 

 at least with a rapidity calculated to impress an idea of that 

 which they exhibit. On such occasions they are easily shot, for 

 they often come quite close to the gunner, being altogether heed- 

 less of his presence, so intent are they on capturing their prey. 



In fine weather, they fly low in the mornings and evenings, 

 and are among the first birds that come abroad, and the latest 

 that retire to their places of repose ; but during the greater part 

 of the day they are to be seen chiefly at a great elevation, 

 apparently that of several hundred yards. Yet I have seen 

 them flying high in rainy weather, when the clouds were sepa- 

 rated by long intervals ; and, from long observation, I am 

 satisfied that no prognostication of the weather can be based on 

 the flight of Swifts and Swallows. These birds fly high or low, 

 according as their prey is abundant in the higher parts of the 

 air, or near the surface of the ground or woods ; and as insects 

 fly lower in the evening and morning, or in damp weather, so 

 the Swifts then descend. 



In dry sunny weather, they frequently utter a long, loud, 

 shrill scream, as they pursue their prey ; but not in such wea- 

 ther alone, for you often hear it before or during rain, especially 

 in the evening. Some have fancied this scream to be an inti- 

 mation given by the male to his mate that he is at hand, and 



