PARENTAL CARE AND NEST-MAKING 299 



shaped like a shallow saucer and is fixed against the vertical 

 walls of cliffs and caves. Those of the first quality look 

 rather like frosted sugar and consist chemically of mucin for 

 the most part. They form the stock of the Chinese Bird's 



Fig. "46. — The sea-swift (Collocalia) and its edible nest. From a 

 specimen. 



Nest Soup, and it is said that 3^ millions used to be sent 

 from Borneo to China in one year. When the nest is taken 

 the bird may make another of inferior quality, yellow rather 

 than white in colour, and obviously eked out with seaweed. 



