EXCLUDING BIRDS FROM RESERVOIRS AND FISHPONDS 3 
of installing a more closely spaced system of cross wires is also worth 
trying as a means of preventing coots, ducks, and other wild fowl 
from alighting on reservoirs. The wires certainly are a menace to 
birds in flight, and finding the proper spacing for each kind, so that 
the danger will be realized and the warning heeded, would seem to 
be a problem capable of solution by further experiment. 
Installation of Wiring Systems 
In a reservoir requiring 400- to 1,000—-foot spans, every third wire 
of the shorter dimension should be a 14-inch cable, as these will 
effectually support the cross wiring. The cables are swung from 
heavy timber posts set in the masonry walls. The point of attach- 
ment of the cable is 15 feet above high-water level, and the posts are 
reinforced by stay wires anchored to beams buried in the ground. 
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for reservoirs about 700 feet across. 
Fictre 1.— Details of supports for long-span wires 
Details are given in figure 1 for the support of wires (6-gage) in 
a reservoir having a maximum span of 700 feet. The all-metal and 
concrete character of this installation makes it strong and durable. 
Figure 2 illustrates a simpler type of support used for shorter wires 
(9-gage), where a high wall was available to compensate for sagging. 
The posts shown are metal and are held in place by the guy wires 
and by the weight of the long wires they support. Similar but 
much larger posts are placed in the reservoir itself at intervals 
under the heavier cables to break the span and thus reduce the 
sagging. The wiring of each reservoir is an individual problem, and 
details as to size of wire, turnbuckles, and supports should be decided 
by a competent engineer. 
Fishponds 
Many ponds for rearing fish, especially ponds at fish hatcheries, 
are small and therefore would seem especially adapted to being pro- 
tected by wiring. The merits of border fencing and overhead wiring 
may be more appreciated after considering the trouble and expense 
involved in the patrolling, shooting, and trapping system. 
