214 THE COMMON (OR BLACK) SWIFT. 



could scarcely see them against the dark wall ; and it was 

 certainly a feat in Nature's perfection of flight to see how her 

 creatures, flying at such a speed, could enter such mouse-like 

 holes in the twilight. On coming round by the Kirkhill many 

 were flying about between the old Abbey wall and the brae 

 above Dennis Work, some of them skimming within a foot of 

 the ground, then disappearing over the brae where the sand- 

 martins breed. They sometimes whisked close past my head, 

 and on coming home by North Street several were flying high 

 around the College steeple spire ; another proof that they just 

 fly where the flies are. One night I stood on the Kirkhill and 

 tried to see how many I could count at one time, but I could 

 not count more than thirty, there were so many gliding and 

 wheeling at one time ; they flew so fast and far, like meteors, 

 over the wall and brae, and around the ruined turrets of the 

 Cathedral. They are amongst the first birds in the air at early 

 dawn, and are the last at night ; and when courting in May, 

 high above the ground, one will be seen to settle on the back 

 of another and sink down together with a piercing scream — so 

 loud and shrill that we well may wonder how such a short, 

 flat, tracheal pipe can do it. 



To corroborate this, White of Selborne says : — " If any person 

 watch them 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, 

 when the business of generation is going on." 



In his little poem of "Dualisms," Tennyson unwittingly 

 describes this — 



" Over a stream two birds of glancing feather 

 Do woo each other carolling together, 

 Both alike, they glide together 

 Side by side." 



They seldom scream when flying singly, but when a number 

 of them are seen gliding and wheeling around the ivied gable 

 of the old Castle on a still evening in May, they seem to revel 

 in company — like little black-winged demons overjoyed at their 

 own perfection of flight. As Tennyson says — 



" Chasing themselves at their own wild will," — 



— unfettered in the midst of love and insect life ; for unless it be 

 exuberance of delight, I can see no other reason for their 

 mingling screams — as otherwise they neither twitter nor sing. 



