SMOKY SWIFT 



They are all of small size, with extremely 

 small and weak feet, and usually do not 

 perch, but rest by clinging to some vertical 

 or oblique surface, supporting the body 

 partly with the tail, whose feathers are in 

 many species stiffened and pointed at the tip 

 for this purpose. The bill itself is very small 

 and short, though the mouth is large and 

 wide when opened. They spend most of their 

 time in the air catching the insects on which 

 they feed, in flight. Their plumage is usually 

 entirely dusky, though sometimes relieved 

 with white areas. Among their most re- 

 markable characters is the great develop- 

 ment of the salivary glands which produce a 

 sticky secretion by which they fasten to- 

 gether the materials of their nest and attach 

 it to cliffs, sides of caves or hollow trees, etc. 

 Swifts are not likely to be mistaken for 

 any other birds except possibly swallows, 

 but their narrower wings, blackish plumage 

 and shrill screaming or twittering notes are 

 characteristics that the bird student will 

 quickly recognize, though the species are 

 often hard to tell apart. In spite of their 

 very different bill, plumage and habits, their 

 nearest relatives appear to be the hum- 

 ming birds, which much resemble them in 

 the structure of their long, narrow wings. 



i. Chaetura cinereiventris fumosa (Salvin) 

 Smoky Swift 



Length, 102 mm. (4.00 in.); tail, 40 mm. 

 (1.60 in.). 



176 



