Results: Several birds appeared dazed or "dopey." The area 
was inspected at two-hour intervals through the day. Not one bird was 
known to be killed by the TEPP. 
Exveriment 2.--At 8 p.m., about one-half hour before sunset, 
a second spraying operation was conducted. This was conducted as out. 
lined under experimental, except that a 6 percent solution of TEPP-40 
was used, and no wetting agent was edded. 
Results: Twelve birds were killed (about 4 percent of those 
hit directly with spray). All of these died within 15 minutes of con- 
tact with the poison spray. The area was inspected at daybreak, and 
twice later in the day. No indication of additional mortality was 
found. The birds carried on their usual activities es though nothing 
had happened. 
Discussion.--A 6 percent stock solution of TEPP-!10 is the 
strongest that could be used within the limits of practicality. The 
ancreased danger to personnel, including the many construction workers 
present on the island, would prohibit the use of a more concentrated 
solution. Possibly sooty terns are more resistant to this poison than 
other animals. Captain Trier and the biologists decided that the two 
tests conducted were sufficient to indicate a conclusion. 
Conclusion,--Because of the unavilability of the proper 
wetting agent (propylene glycol) it is impossible to say whether or 
not the kill from the tests made was the maximum possible with TEPPHO. 
However, because TEPP is completely miscible with water and many birds 
were sprayed in the eyes and open mouth, it appears probable that the 
two tests constitute a good indication of the ability of this poison 
at safe concentration levels, to control sooty terns, Our conclusion 
from this experiment is that TEPP-40 is not a practical agent for the 
reduction of sooty terns on Midway under present conditions of the 
human population, 
Sooty Terns and Aircraft Operations 
Frequency of Sooty Tern Strikes 
Runway 6-24 was opened for. use on June 1, 1957. The eastern 
end of this runway passes between the sooty tern colony and the sea. 
Sooty terns fly over this runway on their way to and from their nesting 
territories. 
During the period from June 1 to June 15, a total of 99 dead 
sooty terns were found on Runway 6-24. These were collected daily by 
the Fire Department pick-up crew. During this period there were a 
total of 36 aircraft landings plus take-offs. This is an average of 
1.15 birds killed per landing or take-off. This is a maximm figure 
because some of these may have been killed by trucks. 
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