
Approximately two-thirds of the albatrosses over the runways 
were determined by their color markings to be from areas within 750 
feet of the runways. Nesting birds from the residential area make up 
less than one-half of 1 percent of the nesting birds over the runways , | 
while unemployed birds from the residential area comprised 5 percent 
of the unemployed population over the runways. Only 1 marked bird 
(unemployed) from Eastern Island has been recorded over Sand Island 
runways. . 
Nest and egg destruction at any stage of incubation shifts 
breeding birds to unemployed status with highly significant increase 
in occurrence over the runways. These birds remain on the island for 
many weeks in unemployed status. Parents which have lost their chicks 
reméin in the area as unemployed birds for some time, but not as long 
as those which heve lost their eggs. 
Sterilization of eggs will cause adults to continue setting 
several weeks after normal hatching date. 
Many young albatrosses can survive (at least until near 
fledging time) after the loss of one parent. Loss of both parents will 
normally, but not always, result in the death of their chicks. 
Destruction of all birds and eggs prior to completion of the 
laying season results in immediate occupation of the area by other 
nesting birds. Destruction of all birds and eggs after laying season 
is complete will eliminate nesting in the area but there will be an 
influx of unemployed birds. 
Present indications are that substantial reduction of the 
hazard to aircraft by killing birds would require the elimination of 
all nesting snd unemployed Laysan albatrosses from an area extending 
at least 750 feet each way from the center of operational runways; that 
this progrem would have to be continued for an unknown number of years 
to eliminate influx of birds from all sources, including the several 
generations of subadult birds raised in the area which are at sea when 
the program is begun, and which will eventually return to nest. 
Evidence indicates that the black-fcoted albatross is such an in- 
significant contributor to the present hazard to aircraft that this 
species may be spared in any killing operation. 
Areas where wind currents are deflected upwards by unevenness 
of land surface are used much more by soaring birds than flat areas. 
Under certain wind conditions the number of birds over the area with 
the highest trees and dunes is 165 times as great as over a level area. 
This suggests that leveling of the land in the vicinity of runways would 
be a good method of controlling the hazard to aircraft presented by 
soaring birds. 
