ii6 Bird -Lore 



away. Over the rim of the chimney we found them coming, singly, by twos, 

 by threes, by fours; making long sweeps toward the earth with the first bound; 

 then mounting high in air with innumerable twitterings, they would be off 

 for the day's experiences. At live minutes of si.x o'clock they ceased to appear. 

 More than eight hundred had been counted within fifteen minutes. Something 

 unexpected now happened. Back into the chimney came rushing the Swifts. 

 In ten minutes ii6 had reentered. What could it mean? Up from the east a 

 dark, threatening cloud was moving. The Swifts had espied it, and all those 

 which by this time were not far afield came hurrying back to the chimney of 

 refuge. 



For many evenings we watched the birds. They always went to roost 

 the same way, going through the same performances. For more than two 

 weeks they continued with us. One day, near the middle of September, we 

 saw from our window that the maple trees over on the hillside were turning 

 yellow and red. "Autumn has come," said my friend. Perhaps the Swifts 

 saw the sign, too, and passed the word that the summer had ended and the 

 air would soon be free of insects. 



That evening, at the hour of gathering about the chimney, 

 The Migration less than one hundred appeared. The great flock had taken 

 up its line of flight and was now far on its course toward the 

 land of perpetual summer. The others lingered for some time, gathering in 

 stragglers, and also those families the young of which had been slow in getting 

 upon the wing; and then, one day they, too, were off to join their fellows 

 in the far South. 



We shall see no more of the Swifts until some day next spring, when we 

 may hear falling to us from the air above a joyous twittering, and, looking 

 up, may catch a view of the first arrival, a black, animated bow-and-arrow- 

 shaped object darting about at such a height that it seems to be scratching 

 its back against the sky. 



The birds usually reach us in April, and within a few weeks 

 The Nest nest-bmlding begins. The structure consists of a bracket work 



of dead twigs, glued together somewhat in the form of a half- 

 saucer. It may be found sticking to the wall on the inside of a chimney. 

 These twigs are the ends of small dead branches broken from the trees by 

 the birds, who grasp them with their feet or bill while on the wing. They 

 are fastened together by a salivary substance secreted by glands in the bird's 

 mouth. Apparently the flow of this gluing secretion is sometimes checked. 

 This is possibly due in part to an unhealthy condition of the bird. At such 

 times, the nest-building must proceed slowly, and its completion may even 

 be delayed until time for the eggs to be deposited. Often nests have been 

 examined which contained eggs, many days before the full number of twigs 

 had been glued in place. 



Before the settlement of this country, the Swifts built their nests on the 



