Birds must be prevented, whenever possible, from contaminating 
potable water supplies and from making destructive forays among 
fishes in hatchery and rearing ponds. Traps and guns have usually 
been relied upon to accomplish this by doing away with the birds. 
It has been demonstrated, however, that water reservoirs not more 
than 1,000 feet in their longest dimension can be satisfactorily and 
economically protected by wiring, and small pools by screening. 
The wiring method can be widely extended, and it is believed that 
im many cases it can be practically combined with partial screening 
to give protection to fishponds. 
There is no question of the general desirability of adopting pre- 
ventive measures rather than continuing to destroy the birds. It 
must be kept in mind that numerous species are protected either by 
Federal or by State law and may not legally be killed except under 
permit for the control of serious damage. The suggestions herein 
presented are recommended chiefly as a result of observations as to 
their effectiveness in actual practice. By their extension our birds 
will receive just so much additional protection—of which they are 
in great need. 
Washington, D. C. Issued September 1936 
It 
