18 CURIOUS HOMES AND THEIR TENANTS. 



BIRDS THAT MAKE EDIBLE NESTS. 



FEATHERED CAVE-DWELLEES. 



Among the lower animals the most notable of cave- 

 dwellers are perhaps the swallows, and the species 

 most worthy the name the two varieties of esculent 

 swallow from whose nests the celebrated bird's-nest 

 soup of the Chinese is made. The birds inhabit the 

 Sunda Islands, Ceylon, Borneo, Java, etc. The nests 

 are built against the sides of steep, cavernous cliffs, 

 so that collecting them is an extremely perilous un- 

 dertaking. They are attached to the face of the 

 rocks much as are the mud-built habitations of the 

 common swallow. These strange nests, however, are 

 constructed in a manner that finds no parallel in the 

 bird kingdom. A number of creatures other than 

 spiders secrete a viscid fluid from which they form 

 threads for the capture of prey or the building of 

 nests. Among fish, the stickleback and the anten- 

 narias bind together the materials that form their 

 nests with glutinous cords drawn from their bodies ; 

 but among birds the only instance of the kind known 

 is the esculent swallow. 



"When about to lay the foundation of her future 

 home, the glands under her tongue, which at this time 

 are so distended as to form two large swellings, give 

 out the sticky fluid of which her nest is composed. 

 The bird presses her tongue, which answers to the 



