_ The Chimney Swift 219 
weather more than the sunshine. The swift, like 
the swallow, feeds on the wing and its movements are 
swift and graceful, as it flies to and fro over its favor- 
ite feeding grounds. At times the wings vibrate very 
rapidly; then again the movement is but slight, pro- 
ducing a series of glides through the air, beautiful to 
see. During this splendid exhibition of flight there 
occurs at short intervals the not altogether unmusical 
sharp and rolling twitter. 
The nest of our swift is one of the most remarkable 
structures to be found among our common birds. 
It is usually placed in a chimney and is composed of 
twigs quite uniform in length and size, woven into 
a semicircular basket. As they seldom frequent the 
ground, there has been considerable speculation con- 
cerning the methods by which the swifts obtain their 
nesting material. It has, however, been found that 
instead of selecting material already scattered about 
by the wind they break twigs from dead limbs or 
trees, while in full flight. These twigs are held in 
place upon the side of the chimney and where they 
cross each other, by a very adhesive saliva secreted 
by the birds. When the nest is completed it is quite 
shallow as compared with that of a robin, being 
usually not more than a fourth as deep, and having 
none of the soft lining usually found in the nests of 
