414 



ZOOLOGY 



forms. The loons and grebes are found in fresh waters. The 

 penguins at the breeding season are gregarious and are often so 

 thick as literally to cover the surface that is level enough to 

 be occupied. They lay one or two eggs, with no pretense of 

 making a nest. The loons and grebes may use flags and rushes 

 for nests. 



FIG. 214. 



FIG. 214. Green Heron (Ardea virescens). Photographed by Dr. R. W. Shufeldt. 



Questions on the figure. To what order of birds does the heron belong? 

 What are its nearest relatives? What can you say of the habits of the order? 



The Longipennes (long-winged) are the albatross, the tern, 

 gulls, petrels, shearwaters, etc. These are aquatic birds with 

 webbed feet and long, pointed wings. They are splendid fliers 

 and mostly good swimmers. There are both marine and fresh- 

 water types. They are gregarious, especially at the breeding 

 season, when they swarm on sandy shores, in the marshes, or 

 on the rocky coasts, where they lay their eggs in crude nests or 

 on the bare rocks. They are the most common birds of the 

 seashore and the high seas. 



