32 WILD LIFE OF SCOTLAND 



hood." In Shetland the swift is only occasional, 

 the others rare. 



The fern-owl is the migrant of the dusk, the 

 swallow of the moth. He occupies the interval 

 between daylight and dark, along with the bat; 

 and, from his habit of circling round the trees, 

 where insect life is most abundant, gets the name 

 of wheel -bird. His distribution is as universal as 

 any of the species of swallow, although the numbers 

 are not so great. " In Mull the monotonous spinning- 

 wheel note was raised each July evening close to 

 both our shooting quarters. In Sutherland he is 

 oftener seen than heard." In Shetland he is 

 commoner than the swallows, probably because he 

 is a ground-builder. 



The sea-swallows, or terns arrive about the same 

 time as the earlier of the land-swallows, and leave 

 with the latest. I have a note of 4th October last 

 year, " Swallows and terns still here " ; and prob- 

 ably they lingered about for a week, or ten days 

 later. Agassiz makes the Arctic tern scud south, 

 just ahead of the first snow-laden northern gale. In 

 spring, I frequently notice the tern and the chimney- 

 swallows, for the first time, on the same day. 



Sea and land swallows are alike in so many 

 particulars that little ingenuity was needed' in 



