Table 3.--Relation Between Nesting Success and Renesting 
the Following Season in Laysan Albatrosses 
:_ Returned, 1957-58 
Fate of nest, 1956-57 : Number :NumberL/ . Number : 
:of pairs:of birds: of birds : Percent 
Chick successfully fledged 75 150 94 63 
Chick died during post-guard 43 86 70 81 
stage 2 
Chick died during. guard stage 2/ 62 126 99 — 79 
Eggs sterile | | 72 147 128 87 
Eggs destroyed late in 71 144 108 75 
incubation stage 
Eggs destroyed early in 78 167 145 87 
incubation period : 

1/ Includes birds comprising marked pairs (column 1) plus birds whose 
mates could not be used in the calculations because they were not 
banded the first season or were not captured the second season. 
2/ | The guard stage is that period from when the chick is hatched until 
it is no longer guarded by one parent while the other is away 
gathering food; the post-guard stage is after the parents have left 
the chick unguarded (Richdale 1952:68 & 77). 
Sex Ratios 
In order to determine whether a highly unbalanced sex ratio 
was responsible for the large proportion of unemployed birds in the 
population, a random sample of 182 apparently unemployed Laysan 
albatrosses was collected in a previously undisturbed area on two 
different days. 
This sample consisted of 82 males and 100 females (45 percent 
males). In addition, 39 more birds were selectively collected; these 
consisted of birds which were dancing together, birds “keeping company," 
etc. This sample contained 19 males and 20 females (49 percent males). 
The total of these samples was 101 males to 120 females (46 percent 
males). 
It was thought that a large number of paired birds which were 
unemployed owing to destruction of their nests might tend to equalize the 
apparent sex ratio of the unemployed birds. The first day's sample was 
segregated into birds with bare incubation patches (birds which pre- 
sumably had nested) and birds with downy or partially downy incubation 
12 
