SWIFTS 301 



of the chimney with a peculiar glutinous saliva secreted by the 

 birds. The completed nest is half basket shaped, composed 

 of small twigs two or three inches in length and unlined. It 

 takes the birds about a month to complete the nest, which 

 might be expected as it requires considerable of the glue to 

 hold the twigs together securely. 



I have observed a certain pair of birds which nested in a 

 chimney where observations could be made by removing the 

 thimble cap in a room below. These birds began building 

 May 15, but it was the middle of June before the eggs were 

 laid and the nest construction continued at intervals for some 

 time after the set was completed. 



One of the parents would appear with a twig and the other 

 immediately left the chimney. The bird then braced itself 

 against the bricks with its feet and tail and proceeded to labor 

 long and earnestly to attach the twig to the bricks, evidently 

 seeking to thoroughly cover the foundation with the gummy 

 saliva. Only two or three twigs were attached the first day of 

 building, and if these were well hardened, as many more would 

 be attached the next day, each bird taking turns at bringing 

 material or sometimes spelling one another in covering with 

 saliva the twigs already attached, but almost invariably as 

 soon as one bird entered the chimney, hovering over the open- 

 ing a second, uttering its characteristic rattling chirp, the other 

 one would prepare to leave, and as one dropped down with 

 slightly fluttering wings the other would be scrambling upwards 

 along the chimney side, to take wing and fly away. 



The eggs were laid every other day, and the first egg hatched 

 in nineteen days, the others at daily intervals, so that the first 

 egg hatched in nineteen days and the last one of the four in 

 twenty-two days from the time when the first egg was laid or 

 the interval between laying the last egg and the last one to 

 hatch was only sixteen days, each egg hatching in a day less 

 time than the one preceding. My observations were inter- 

 rupted before the young had grown enough to be studied under 



