C. Studies of Control Methods 
Habitat Control 
Observations have shown that sooty terns will not nest in 
hard=surfaced areas, areas bare of vegetation, or areas completely 
grown up in dense brush or trees. Therefore, by modifying the habitat 
accordingly, the birds can be prevented from nesting in certain areas. 
However, this does not prevent them from flying across runways which 
lie between nesting colonies and the sea. For habitat manipulation 
to be successful as a control measure would require that a very large 
acreage of Sand Island be rendered unsuitable as nesting grounds. 
None of the above methods of habitat manipulation would be practical 
under present circumstances. Hard-surfacing would be too costly, un- 
less the area were also needed for water catchment. To maintain bare 
sand for any period of time would be impossible and impractical. It 
would be subject to wind erosion, and would soon begin to develop low 
herbaceous vegetation, rendering it ideal nesting habitat for the 
sooty terns. Planting the area to brush and trees would only 
aggravate the far more serious albatross problem. 
Bombing 
Several preliminary experiments at bombing were conducted. 
The bombs were constructed of tin cans (12 oz. to 40 oz.) containing 
a core of plastic explosive surrounded by shrapnel. The shrapnel 
used was that available locally -- nails, granite gravel, and fine 
scrap metal. The bombs were linked together with primer-cord and laid 
in a pattern about 20 feet apart over the area where the terns were 
expected to alight. When the birds settled among them, they were 
detonated electrically by a concealed observer located a safe distance 
away . 
The limited experiments were promising, but the method will 
have to be perfected by further experiment before it can be recommended. 
The size and amount of shrapnel used is especially important. Steel 
shot pellets would be preferable. Further work is necessary to deter- 
mine the most efficient size bomb, the amount of explosive to use, and 
the pattern in which they should be laid. It remains to be determined 
whether they would be most effective during the incubation period, or 
during the prenesting flocking period. 
When perfected, bombing should be a very useful supplement 
to other control methods, if used sparingly and judiciously. 
Shooting and Harassment 
During the summer of 1958, the Navy attempted to exterminate 
the sooty tern colony on Sand Island by shooting and clubbing. 
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