CHIMNEY SWIFT 285 



yet been made good." Since 1903 the birds here in New England have 

 been decimated by several minor storms but have quickly recovered 

 their loss. 



Fall. — Fall comes early in the yearly cycle of the swift's life. At 

 the end of the summer there is a long journey before the birds, old 

 and young, to the warm air of the Tropics where they can find food 

 throughout the winter months. 



Late in July and earl}^ in August we often see small groups of 

 swifts in the air, evidently preparing for migration. These flocks 

 are doubtless made up of our local birds, those that have spent the 

 summer in our vicinity, and they are accompanied, presumably, by as 

 many of their young as are on the wing. They travel such long 

 distances through the air, often curving round and round a chimney 

 or chui'ch tower, that they derive a good deal of exercise from the 

 flights — exercise that must serve to strengthen the wings of the young 

 birds. 



Under date of August 7, 1917, my notes mention this habit. 'Tn 

 these exercising flights, as I take them to be, the birds fly mostly in 

 long curves ; they are really circling, although they may turn at any 

 time to either side. The birds, a dozen or more of them, are sailing 

 in a great ring; they suggest bits of wood floating in an eddy of a 

 slow-moving stream. They are far from one another, flying silently, 

 mainly on set wings. One veers toward another, which quickens its 

 pace by rapid, flickering wing beats. A chase is on. One or more 

 birds join in, giving the long chatter. Now they hurry through the 

 air, close together. When one comes near another, it may raise its 

 wings in a V above its back, soaring for a moment. The chases are 

 soon over, however; the birds seem to lose interest in speed and re- 

 sume their circular, soaring flight. They often turn out from the 

 circle, tilting to one side, the outer wing uppermost. 



"During the middle of the day I do not see the swifts gathered 

 about the house; it is chiefly in the morning and evening that they 

 are most active. This evening two birds, close together, flew slowly 

 over my head at a low elevation. One gave the long chatter and 

 chips alternatel}^, but in a quiet way with little staccato quality." 



It is at about this time, the first two weeks of August, that we 

 see evidence of molting in our local swifts. As they fly overhead we 

 notice a narrow gap in their wings where a flight feather or two 

 is missing, and in every case the little gap in one wing corresponds 

 almost exactly with the gap in the other, but this slight bilateral 

 loss of wing surface seems to hinder the birds' flight little, if at all. 

 Apparently molting does not cripple them, as it does many wood- 

 land birds; indeed, the swift, spending the hours of daylight in the 

 sky, must not be disabled for even a single day. 



