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 
