not fly, were found floating in the lagoon or washed up on the reef 
and the beaches. This mortality is difficult or impossible to assess. 
One possible way to compare this mortality on a year-to-year basis 
could be to count the number of dead birds along the beaches. These 
counts would include birds which left the island, were drowned, and 
washed up on the beaches, and also starving birds which wandered down 
to the beaches and died without leaving the island. Such counts would 
include only a small fraction of the total post-fledging mortality, 
but it should provide a fairly reliable index for year-to-year varia- 
tions. On 16 July the entire beach of Eastern Island was walked, and 
all dead young albatrosses were counted, with the following results: 
Laysan albatross, 409; black-footed albatross, 14. 
The date was believed to be about right for counting the 
Laysans, as a maximum number of dead chicks were present at that time. 
However, for the black-foots, a count made two or three weeks earlier 
would give a better index. 
On the basis of hearsay, a heavy mortality due to sharks was 
anticipated. It was said that sharks throng into the lagoon when the 
young gooneys are just learning to fly. Such did not appear to be the 
case in the summer of 1957. The members of the underwater demolition 
team which was working in the lagoon all spring and summer reported no 
large sharks during June and July, although they had seen a few earlier 
in the spring. Of course there are always a few sharks, including an 
occasional large one, around the reef. But there was no evidence to 
indicate that there was an influx of sharks, or that they were feeding 
on young albatrosses. 
The situation was different in the summer of 1958, however. 
At Midway, large sharks were frequently observed from low-flying air- 
craft. Many of these, identified as tiger sharks (Galeocerdo cuvieri), 
were from 10 to 15 feet long. A number of fair-sized hammerhead 
sharks (Sphyrna lewini) also were seen. Large sharks were also common 
during this period at Kure Atoll and at Pearl and Hermes Reef. Several 
people reported seeing sharks attacking waterlogged juvenile albatrosses 
in the lagoon. 
On the basis of general impressions, it would seem that the 
majority, probably at least two-thirds, of the albatrosses which reach 
the flying stage are successful in leaving Midway Atoll. 
Summary of mortality of juvenile albatrosses.--On the basis 
of counts made at different times of the nestling season, and on known 
mortality rates for different periods, as presented above and in the 
1956-57 report, we may attempt an estimate of the total number of young 
albatrosses which were fledged at Midway Atoll in the 1956-57 season. 
The number of eggs laid is based on the November population estimates 
(see Kenyon, et al. 1958). The number of young fledged is based either 
on total counts (for black-foots, as presented above), or on estimates 
made on the basis of known mortality rates on sample plots (Laysans) 
subsequent to total counts on those areas. From these figures, the 
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