SUMMARY 
This report covers investigations by the Bureau of Sport 
Fisheries and Wildlife in 1957 and 1958 which are a continuation of 
1956-57 studies (Special Scientific Report - Wildlife, No. 38) to 
determine the relation between bird populations and aircraft opera- 
tions at the U. §. Naval Station, Midway. Islands, and to develop a. 
management program that will satisfactorily reduce the-hazard to 
aircraft. The approach to this study included the objective of 
avoiding a reduction of any bird population to the point of endanger- 
ing the continuing existence of the species. 
Albatrosses 
The total world population of Laysan albatrosses (Diomedea 
immutabilis) is estimated at 1,500,000; this includes about 800,000. 
sexually mature adult breeding birds, of which about 560,000 nest in 
any given year. The total world population of black-footed albatrosses 
(D. nigripes) is estimated at 300,000; this includes about 160,000 
sexually mature adult breeding birds, of which about 110,000 nest in 
any given year. 
Laysan and black-footed albatrosses now nest only in the 
Hawaiian Archipelago (with the: exception of a few pairs of black- 
foots on Tori Shima in the Izu Islands). At least 96 percent of the 
world population of both species uses only four atolls: Midway, Pearl 
and Hermes, Lisianski, and Laysan. Midway, utilized by 35 percent of 
the nesting Laysan albatrosses and 16 percent of the nesting black- 
footed albatrosses, is second in importance to Laysan Island, which is 
utilized by 46 percent of the nesting Laysans and 62 percent of the 
nesting black-foots. 
The age at which Laysan and black-footed albatrosses normally 
return to the breeding grounds for the first time is not yet known. The 
youngest found to date were 4 years old (one black-footed and one 
Laysan albatross). . 
The age at which these species of albatrosses normally begin 
to nest is not known; the youngest known-age bird found on a nest was 
a 7~-year-old Laysan albatross. 
Albatrosses do not habitually nest at the site where they were 
hatched. The majority return to the same atoll, but may take up 
residence on another island, or at a different location on the island 
where they were hatched. 
The pair bond in Laysan albatrosses normally remains intact 
from season to season until broken by the death or disappearance of 
one of the partners. The establishment of a new pair bond usually. 
takes more than one season. 
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