Albatross soaring in relation to thermals.--It has been 
suggested that albatross soaring may be influenced by thermal up- 
drafts. Detectable thermal currents exist over Midway runways only 
on occasional clear, hot, dead calm afternoons in the summer months 
when albatrosses are scarce or absent. At all other times of the 
year any thermals which might exist would be so deflected and their 
effects so overridden by the continual moderate to strong winds that 
they could not be detected and would be of no use to albatrosses for 
soaring. 
If thermal updrafts played an important role in albatross 
soaring, large numbers of soaring albatrosses would be expected 
over the east end of runway 6-24 (stations Se and 5w); such is not 
the case (Figs. 4 and 5). 
E. Conclusions and Recommendations 
(1) At the U. S. Naval Station, Midway Islands, large 
numbers of Laysan albatrosses create a considerable problem in air- 
craft operations during part of the year, especially from early 
November to the middle of December. Bird strikes cause frequent 
damage to propeller-driven aircraft. Most damage has been minor, 
but occasionally expensive repairs and long grounding of aircraft 
are necessary. No crashes or fatal accidents have ever occurred, 
but at times strikes have impaired operations essential to national 
defense. If such operations are to continue on a dependable basis, 
the frequency of albatross strikes must be reduced. 
(2) Laysan albatrosses have been extirpated from some of 
their former nesting islands in the North Pacific, and now breed 
only on the Leeward Islands, and the island of Niihau, in the 
Hawaiian Archipelago. The majority nest on Laysan Island and Midway 
Atoll; 35 percent of the total breeding population nests on Midway. 
Under these circumstances, no large-scale reduction in numbers would 
be advisable from the standpoint of perpetuation of these species and 
only to be considered if absolutely essential to national defense. 
(3) Experimental killing programs have demonstrated that it 
would take a number of years, probably at least 3 to 5, to reduce the 
population sufficiently to achieve any practical lowering of the strike 
frequency. . Killing of albatrosses within 750 feet of the operational 
runway reduced neither the number of birds soaring over the runway nor 
the frequency of strikes. It is concluded that killing is an im- 
practical means of obtaining immediate reduction of the aircraft 
hazard. 
(4) Observations indicate that clearing and leveling the 
shoulders of the runways for a distance of about 750 feet on either 
side of the centerline will eliminate updrafts which are conducive to 
albatross soaring over these runways. This should reduce the strike 
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