POND, LAKE, AND STREAM 37 



and mosquitoes are preyed upon by frogs and fish ; and 

 frogs and fish are often caught by kingfishers and herons. 



Smaller animals often serve as food for the larger ones. 



Flies, mosquitoes, and frogs cannot be easily found in 

 the winter. The first two hibernate in sheltered places, 

 such as cellars and caves ; the last pass the winter in the 

 mud of lakes and ponds. As soon as the chilly nights 

 make winged insects scarce, the swallows leave us. When 

 the frogs take up their winter quarters and ice begins to 

 form on the water, the herons and ducks also move south. 

 When do the different migratory birds leave your locality ? 



Plant life also sleeps through the long, cold winter in 

 buds, roots, and seeds. By the warmth of spring plants are 

 awakened to new growth and animals to renewed activity. 

 Then the migratory birds return to their northern homes. 

 When do they arrive in your locality ? 



