ABSTRACT 
The purpose of this study is to determine the extent to 
which certain species of birds contribute to the hazard to aircraft 
at Midway; to learn more about the population dynamics and habits of 
these species to determine what type of control measures might be 
possible without endangering the species; and to test methods of 
control which are suggested. Most of the study has been devoted to 
the two species of albatrosses and the sooty terns nesting at Midway 
because of the current belief that these species offered the greatest 
danger to aircraft safety. 
Albatrosses 
The total albatross populations were estimated on the Midway 
Islands as 10,300 black-footed and 131,000 Laysan on Sand Island, and 
5700 black-footed and 105,000 Laysan on Eastern Island. This compares 
with an estimated 116,000 black-footed and 647,000 Laysan in the entire 
Hawaiian chain, which comprises almost the entire breeding grounds of 
these two species. 
Albatrosses have 2 highly developed homing instinct when they 
are engaged in nesting activities; greater when setting on eggs than 
after the eggs have hatched. Of 18 Laysan albatrosses removed from 
their nests at Midway and shipped by aircraft to distant points around 
the North Pacific, 14 returned from distances ranging from 1315 miles 
to 4120 miles, 
All recorded airplane strikes of albatrosses have occurred dur- 
ing daylight hours; these birds are rarely in flight over Midway at night. 
The most accurate information on the frequency of strikes is 
from control tower operators' observations from April 8 to May 31, 1957, 
in which period 29 albatrosses were struck during 25 out of a total of 
388 landings and takeoffs; about 5 percent of operations resulting in 
strikes. Black-footed albatrosses contribute only about 1 percent of 
the total strikes. 
Since Midway has been used as an airbase there are no records 
of human lives being lost or of aircraft having crashed because of bird 
strikes. 
Damage from bird strikes to 7 planes was reported between 
November 20, 1956 and May 31, 1957. This damage was incurred during 
1638 landings and takeoffs, about 99 of which resulted in bird strikes. 
Therefore damage to planes occurred in 0.4 percent of landings and 
takeoffs. 
Observations of color-dyed albatrosses soaring over the run- 
ways showed these to be made up of about one-half nesting and one-half 
unemployed birds. Since population estimates show a ratio of 5 nesting 
birds for each unemployed individual, it follows that an unemployed bird 
is five times as great a hazard as one that is nesting. 
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