1 66 NATURE'S STORY OF THE YEAR 



might possibly meet and soar up for the purpose 

 of travelling in company to some roost-place at a 

 great elevation on a mountain, as appeared to be 

 the case with a certain allied species in India ; but 

 it would seem that our birds go up sheer vertically 

 or at any rate with no preference for any lateral 

 direction. At the same time it certainly appears 

 to me that swifts from outlying villages near 

 Cheltenham join at evening the group over the 

 larger town, and they may do the same thing in 

 other districts. 



The assembling of birds from a considerable 

 area to roost together is a well-known incident, 

 instances of which commonly occur in the case of 

 rooks, starlings, and sparrows (near London, at 

 least). And this habit was obviously a charac- 

 teristic of the chimney swift of North America 

 (Hirundo pelasgia), which I saw in Canada. 



At Ottawa, a lovely half-barbarous, half-Parisian 

 town, you can see in the daytime a few pairs of 

 these birds, and, travelling by rail, one is seen 

 occasionally if a sharp look-out is kept Towards 

 evening at Ottawa, however, you suddenly become 

 aware that many of them are flying near the great 



