POND, LAKE, AND STREAM 33 



sometimes catches a fish ten inches long. If he sees you 

 watching him, he will spread his win^s, slowly rise, and fly 

 to some undisturbed spot. How does his flight compare 

 with that of the teal ducks ? 



A great many herons build their nests close together. 

 These colonies are called heronries. They are generally 

 located 011 an island in a lake, or in a river bottom. The 

 best-known heronry in Minnesota is on Crane Island, in 

 Lake Minnetonka, about fifteen miles from Minneapolis. 

 On this island hundreds of herons have built their nests on 

 the large trees for so many summers that even the Indians 

 could not tell when the herons first came there. If your 

 boat passes the island, you see the great blue herons and 

 the black-crowned night herons perched on the trees 

 along the shore ; here and there the large nests appear as 

 bundles of sticks. Minnetonka is now the most popular 

 summer resort in Minnesota ; large and small steamers, any 

 number of sailboats, and hundreds of rowboats move about 

 on the lake all summer; still the herons and the double- 

 crested cormorants continue to inhabit Crane Island. It 

 was, however, found necessary to make them wards of the 

 state, as young boys and old fools disturbed the birds so 

 much that their number began to decrease. 



From their colonies the blue herons leave in the morning 

 for their feeding grounds. They often fly as far as fifty 

 miles and more, but always return towards evening. 



When it gets so cold that frogs, snakes, and slugs seek 

 their winter quarters, and the fish retreat into deeper 

 waters, then the cranes leave us, because they can no longer 

 find their accustomed food. 



20. Larger Blue Flag. Iris versicolor. 



MATERIAL : Blue flags with rootstocks, flowers, and seed pods. 

 Observe : How insects fertilize the blue flags. 



