14 OUR NATIVE BIRDS 



known on the lake after this destruction of the fish, but 

 swans still visit the lake in spring and fall. 



Great blue herons and cormorants continued fairly 

 numerous until in the summer of 1895 or 1896, when 

 the water was so low that the bullheads died ; then 

 these birds left the lake. In the autumn of 1896, by 

 far the greater part of the lake was a mud-flat, and 

 there were only a few ducks found on it. 



In the spring of 1897 the water again rose to an 

 average depth of about two and one-half feet, and in 

 that autumn nearly all kinds of ducks were again 

 present in great numbers. An astonishing number of 

 coots bred there or arrived in fall. 



The spring of 1898 was late in coming, but there 

 was no relapse into winter. When the lake was well 

 clear of ice, the spring shooting season had closed, and 

 great numbers of ducks, of different species, bred on 

 the lake because they were not disturbed by hunters. 

 The average depth of the water was about two and one 

 half feet in August. On the twenty-fourth of that 

 month I saw a flock of red-heads, mostly young, which 

 I estimated to contain about 800 individuals. Blue- 

 winged teal and mallards were also very numerous 

 and there was a sprinkling of other species. The num- 

 ber of coots was almost incredible. Following an ir- 

 regular shore fringe of rushes with a field-glass for 

 about five miles, I estimated the number seen from 

 one point to be about 10,000. The change in the water 

 level was, of course, accompanied by a corresponding 

 change in aquatic plants. In the summer of 1898 



