Pairs return to the same nest site each year if the site 
remains undisturbed; none have been found to move more than 6 meters. 
Approximately 67 percent of the total breeding population 
will nest in a given year. Birds successful in rearing chicks show 
less tendency to return (63 percent) the following year than do those 
that are unsuccessful (87 percent). 
The sex ratio of unemployed birds is approximately equal 
(46 percent males). 
Banding recoveries indicate that the pelagic distribution 
of both species covers the entire North Pacific Ocean from about 25 
degrees north latitude to the southern Bering Sea. 
Detailed studies of the breeding cycles of both species will 
be reported in the ornithological journals. 
During the 1956-57 season, juvenile mortality (from egg- 
laying to fledging) of Laysan albatrosses was 40 percent on Sand 
Island and 33 percent on Eastern Island. Corresponding figures for 
black-footed albatrosses were 58 percent and 36 percent. 
In January 1958, a tidal wave destroyed about 42 percent of 
the black-footed albatross nests on Sand Island of Midway Atoll, and 
about 43 percent at Pearl and Hermes Reef. A similar amount of 
mortality probably occurred throughout the greater part of the Leeward 
Chain. Laysan albatrosses were virtually unaffected by this high 
water -- mortality was 6 percent at Pearl and Hermes Reef. 
In November,1957, immediately after the birds had returned 
to their nesting islands, the frequency of albatross-aircraft strikes 
reached a peak of 0.40 strikes per daylight landing or takeoff. As 
soon as nesting was well underway in December, strikes dropped to 
about half this frequency, and gradually declined throughout the rest 
of the season. 
Seven percent of the strikes (or 1 percent of all daylight 
landings and takeoffs) resulted in damage to aircraft. Most of this 
damage was minor; none of it was serious enough to place the aircraft 
in immediate danger of crashing. No crashes from any cause have ever 
been reported at Midway during its 23 years of use as an airfield. 
Albatross strikes were five times as frequent along portions 
of the runway bordered by high trees, dunes, and revetments, which 
create updrafts favorable for albatross soaring, as they were along 
sections where the shoulders were level. 
Strikes were twice as frequent when wind directions were 
such as to create the strongest updrafts along the runway. 
47 
