200 ROCK-SWALLOW 



any day all through February ; they did not travel in 

 flocks, but singly, though as a rule many birds were 

 in sight and sound of each other. They travelled in 

 a singularly leisurely manner, stooping or rising and 

 sweeping in wide circles about, hawking after flies, 

 and continually emitting their clicking, jarring and 

 twittering notes; and the direction of their flight 

 always appeared to be east of north. This would 

 eventually bring them to the Atlantic side of the 

 continent, and their entire journey would form an 

 immense curve at least a thousand miles longer than 

 it need be, since a direct line to their breeding-ground 

 would be on the Pacific side. 



One year in April, a full month after the last 

 of the swallows had vanished, there occurred one of 

 those rushes of belated migrants which were not 

 uncommon, and I then saw a lot of rock-swallows, 

 and saw them well, as I was out on horseback and 

 they passed directly over me, not more than thirty 

 feet from the ground. They were not now travelling 

 in the way I had been accustomed to see them; they 

 were packed together in a flock just like our chimney- 

 swallow on its migration, flying at their greatest 

 speed and due north. This slight alteration in the 

 direction of its flight and complete change in its 

 manner of travelling gave me the idea that in the 

 early stages of migration in the rock-swallow and other 

 species the pull of the north is not so powerful and 

 insistent as to prevent the birds from deviating to 

 this side or that according to the abundance of food 

 or other conditions of the territories they pass over, 



