
during the present study. Ninety-seven percent of all aircraft 
arrivals and departures at Midway took place during daylight hours.* 
Frequency of Albatross Strikes 
During the period from November 20, 1956, to May 31, 1957, 
records of landings anc takeoffs by all types of aircraft at Sand 
Island, Midway Atoll, were kept by the Air Route Traffic Control unit. 
During this period (except December), the Station Fire Department 
picked up all albatrosses killed on the duty runway (Runway 15-33); 
pickups were made every day, or every few days, depending on the number 
of birds killed. (In Table 4 are presented the number of landings and 
takeoffs and the number of birds killed on the runway. 
All of the dead albatrosses picked up on the runways were not 
killed by aircraft strikes. Many are killed by trucks. Many are killed 
by being throtm to the ground by the slip-stream or propeller backwash, 
without actually striking the plane. For this reason the number of birds 
picked up greatly exceeds the number actually struck by aircraft. Un- 
fortunately data are not available on the number actually struck by 
aircreft during the entire period of study. Such data ere available for 
only a relatively short period during the spring. 
To determine how many of the dead albatrosses on runways were 
killed by aircraft, the Control Tower operators carefully observed each 
incoming and outgoing plane through binoculars during the period April 
8 to May 31, 1957. During this period there were 388 landings and take- 
offs, <A total of 29 albatrosses were struck during 25 landings or take- 
offs; 21 planes struck one bird, and 4 planes struck two birds. During 
the same period, 100 dead albatrosses were picked up from the runways. 
If these figures are considered representative of the entire 
period of November 20, 1956 through May 21, 1957, the lall of 397 
albatrosses on the runway would indicate that approximately 99 aircraft 
struck a total of 114 albatrosses, and 1629 aircraft struck none. On 
the average, one out of 16 planes landing or taking off struck a bird. 
Weights of Albatrosses 
Significant in appraising the hazard to aircraft presented by 
collisions with these birds and in designing protective features is a 
knowledge of their weights. Seventy-four Laysan albatrosses, killed on 
the study plots, were weighed (Figure 12). The lightest weighed 4.0 
pounds, the heaviest, 6.5 pounds. The mean weight was 5.4 pounds. The 
heaviest Leysan albatross we found was a recently-returned incubating 
bird which weighed 8.12 pounds alive; its weight fell to 5.94 pounds 
before it left the nest for another period of feeding at sea. 
A series of 30 black-footed albatrosses were weighed alive 
(Figure 12). The weights ranged from 4.75 pounds to 9.12 pounds; the 
mean weight was 6.8 pounds. 
* Information furnished by the Air Operations Office, Midway Naval Station. 

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