146 THE NATURAL HISTORY 



thatched roofs. We remember but one instance where they breed 

 out of buildings ; and that is in the sides of a deep chalkpit near 

 the town of Odiham, in this county, where we have seen many 

 pairs entering the crevices, and skimming and squeaking round 

 the precipices. 



As I have regarded these amusive birds with no small attention, 

 if I should advance something new and peculiar with respect to 

 them, and different from all other birds, I might perhaps be 

 credited ; especially as my assertion is the result of many years 

 exact observation. The fact that I would advance is, that swifts 

 tread, or copulate, on the wing : and I would wish any nice 

 observer, that is startled at this supposition, to use his own eyes, 

 and I think he will soon be convinced. In another class of 

 animals, viz. the insect, nothing is so common as to see the different 

 species of many genera in conjunction as they fly. The swift is 

 almost continually on the wing ; and as it never settles on the 

 ground, on trees, or roofs, would seldom find opportunity for 

 amorous rites, was it not enabled to indulge them in the air. If 

 any person would watch these birds of a fine morning in May, as 

 they are sailing round at a great height from the ground, he would 

 see, every now and then, one drop on the back of another, and 

 both of them sink down together for many fathoms with a loud 

 piercing shriek. This I take to be the juncture when the business 

 of generation is carrying on. 



As the swift eats, drinks, collects materials for it's nest, and, as 

 it seems, propagates on the wing ; it appears to live more in the 

 air than any other bird, and to perform all functions there save 

 those of sleeping and incubation. 



This hirundo differs widely from it's congeners in laying invari- 

 ably but two eggs at a time, which are milk-white, long, and peaked 

 at the small end ; whereas the other species lay at each brood 

 from four to six. It is a most alert bird, rising very early, and 

 retiring to roost very late ; and is on the wing in the height of 

 summer at least sixteen hours. In the longest days it does not 

 withdraw to rest till a quarter before nine in the evening, being 

 the latest of all day birds. Just before they retire whole groups 

 of them assemble high in the air, and squeak, and shoot about 

 with wonderful rapidity. But this bird is never so much alive as 

 in sultry thundry weather, when it expresses great alacrity, and 

 calls forth all it's powers. In hot mornings several, getting to- 

 gether in little parties, dash round the steeples and churches, 

 squeaking as they go in a very clamorous manner : these, by nice 



