392 



ZOOLOGY 



animals. It also swallows undigestible matters, such as stones, 

 which probal)ly aid it in triturating its food. The nest consists 

 of a hollow scooped out of the earth, into which about thirtj' 

 eggs are laid. Ostrich feathers are used for ornament, and so 

 important is the commerce in these articles that ostriches are 



Fig. 3.50. — Common tern (Stf'riia hirundo). 



extensively farmed in South Africa, southern California, and 

 Arizona. The feathers are cut off and not pullcHl out, so that 

 the operation of gathering the feathers is a painless one for the 

 bird, but attended with some risk to the o]3erator. 



Tlie swimmers, or Natatores, comprise the ducks and geese, 

 the pelicans, the petrels, the gulls and terns, and the divers. 

 Of the geese, the wild goose, or Canada goose, is mcjst commonly 

 seen in its migrations. (.)f the native ducks we ha^'e many 

 kinds, almost all rajiidlj^ disappearing before the " sportsman." 

 The pelicans are large fish-eating birds, with a huge bag-like 



