566 , The Roller-like Birds 



fastened gave away sooner than the cement with which it had been secured. 

 The eggs number from three to five and but a single brood is reared in a 

 season. 



Vaux and Needle-tailed Swifts. The only other North American member 

 of the genus is the rare Vaux Swift (C. vauxii) of the western United States, 

 chiefly beyond the Rocky Mountains, which is similar to the Chimney Swift, 

 but smaller and paler. The habits are also similar, except that most of them 

 still continue to employ the hollow trees for nesting sites. Of the Old World 

 species, mention may be made of the Needle-tailed Swift (C. caudacuta) of 

 eastern Asia, which spends the winter in China, Japan, and even Australia, 

 and has twice strayed as far as England. It is a gregarious species, nesting in 

 communities in holes in rocks, cliffs, and hollow trees, and is said to have a 

 weak, Swallow-like note. 



West Indian and Black Swifts. In the second genus (Cypseloides)^ although 

 the feathers of the tail are somewhat pointed, they are not so stiff or spinous as 

 in the last, and the plumage is of uniform color or sometimes with a collar of 

 rufous in the male ; the seven forms are all natives of the New World and par- 

 ticularly of northern South America. The West Indian Swift (C. niger), a bird 

 about six inches in length, is blackish brown throughout with a slight, metallic 

 reflection and paler throat and forehead. A similarly colored but larger form 

 (C. n. borealis] is our Black or Cloud Swift, which ranges through the moun- 

 tains of Central America and western North America to British Columbia, but 

 is of very local distribution within our borders. They are extremely sociable 

 birds, rarely seen singly even during the breeding season, and frequent high, 

 precipitous cliffs mostly among the lofty mountain ranges. It is a rather silent 

 bird at all times, and never alights on the ground. Its nest and eggs appear 

 to be unknown. 



Swiftlets. The pygmies among the Swifts are the so-called Swiftlets (Col- 

 localid), some of which are perhaps better known as the manufacturers of the 

 famous edible birds' nests which are so highly esteemed as an article of food in 

 certain eastern countries. They are, as implied by the name, small birds, 

 none exceeding five inches and some falling under three and a half inches in 

 length, mostly of a sooty black and brownish color, often lighter below, with a 

 light or even white rump band. There are, according to a recent revision by 

 Oberholser, upward of thirty forms, all of Old World distribution and ranging 

 from the Indian and Malay countries through the Papuasian and Pacific islands 

 to Australia and the Fiji Islands and west to the Mauritius and Seychelles. As 

 they are resident wherever found, there has been a tendency to develop into local 

 races. It was formerly supposed that the nests, which were attached to the 

 walls of caverns, were made of algae or minute seaweeds which had been partially 

 digested by the birds, but it is now known that the best quality of nests are 

 composed entirely of mucus which is secreted by the large glands in the throat. 

 Not all of the species produce edible nests, as some do employ mosses and other 

 plants in their construction, and when the edible species have been robbed of 

 the first and second nests, the supply of saliva seems to give out and vegetable 



