l6o WINGED ROBBERS AND NEST-BUILDERS. 



Their summer resorts are in the high northern 

 latitudes. In their migrations a few of them re- 

 main within the limits of the United States, but 

 the majority pass further on — to the Hudson Bay- 

 country and the Arctic Ocean coast, where they 

 frequent the shallow borders of lakes, rivers and 

 deluged marshes, among the reeds and sedges, to 

 build their nests. The mother grebe is very awk- 

 ward on the land. It is impossible for her to walk 

 gracefully. She moves by jerks, as if she was fet- 

 tered. Her legs are situated so far behind that 

 she can keep her balance only by sitting upright, 

 like the auks and penguins. As it is difficult for 

 her to move around readily on the land she takes 

 to the water, where she is perfectly free to build 

 her floating raft. This is composed of reeds, 

 rushes and other aquatic plants, thickly matted 

 together and slightly raised above the surface of 

 the water. After the boat is finished and well 

 anchored to prevent it from being carried away by 

 the winds or currents, the builder makes a shallow 

 cavity on the top and lays four light green eggs. 

 During the season of incubation, which lasts a 

 month, she is tossed about on the wavelets, keep- 

 ing a sharp lookout for minks, otters, and other 

 furry fishers and egg-eaters that abound in these 



