Birds on Midway — FISHER 
109 
followed in estimating the populations. The 
results of the more extensive censuses mentioned 
above are presented in Table 1. 
In this table the trend of populations can be 
observed in some species, but usually only in a 
general sort of way because different observers 
were involved and because allowances must be 
made for different months of the year. However, 
in many instances direct comparisons between 
the figures for 1922, 1945, and 1946 may be 
made. For example, the period of nesting and 
caring for the young in the albatrosses covers 
the months from November to May or June. 
Hence, data in any of these months can be used 
for comparative purposes, although one might 
expect that mortality from natural causes would 
reduce the number of adults in the latter part 
of the reproductive period. 
The populations of both species of alba- 
trosses, Bonin Island Petrels, Hawaiian Terns, 
Wedge-tailed Shearwaters, Red-tailed Tropic 
Birds, and Gray-backed Terns increased greatly 
from 1922 to 1945 despite the adverse effects 
of the war. Of these the first four species showed 
considerable gains in the 18 months between 
the observations of 1945 and 1946. The table 
would seem to indicate an increase in the num- 
bers of Christmas Island Shearwaters, Bulwer’s 
Petrels, and Sooty Terns, but the month’s dif- 
ference in census dates is important; these 
species are just moving into the islands in late 
April and early May. This may explain the rela- 
tively few Sooty Terns found by the "Tanager” 
Expedition in 1922 and may explain the absence 
of Christmas Island Shearwaters and Bulwer’s 
Petrels in April, 1922. 
Populations of Blue-faced Boobies, Red- 
footed Boobies, frigates, and noddies have ap- 
parently never been abundant and there has been 
little change in numbers in the last 25 years. 
Noddies were much more abundant in Decem- 
ber, 1946, than in May, 1945; this may be due 
TABLE 1 
Estimated Numbers of Birds on Midway Atoll* 
WETMORE 
APRIL, 1922 
GRANT 
APRIL, 1922 
FISHER, 
BALDWIN 
MAY, 1945 
FISHER 
DEC., 1946 
Black-footed Albatross 
4,000 N 
5,000 
53,000 N 
69,000 N 
Laysan Albatross 
5,000 N 
5,000 
11 0,000 N 
145,000 N 
Wedge- tailed Shearwater 
common 
5,000 
62,000 N 
0 
Christmas Island Shearwater 
p 
0 
400 N 
0 
Bonin Island Petrel 
many N 
5,000 
25,000 N 
30,000 
Buiwer’s Petrel 
p 
0 
600 N 
0 
Red-tailed Tropic Bird 
20 
300 
19,000 N 
25 
Blue- faced Booby 
2 
3 N 
5 
Red-footed Booby 
50 N 
500 
450 N 
150 
Brown Booby 
12 
500 
0 
0 
Frigate (Bryan, 1902, saw 60) 
100 N 
60 
100 
Mallard Duck 
0 
2 
Laysan Rail 
abundant 
5,000 
0 
0 
Pacific Golden Plover 
many 
1,000 
250 
2,500 
Bristle-thighed Curlew 
several 
100 
20 
200 
Ruddy Turnstone 
common 
5,000 
350 
9,000 
Sanderling 
0 
0 
0 
2 
Wandering Tattler 
1 
50 
0 
2 
Gray-backed Tern 
300 N 
750 N 
0 
Sooty Tern 
1,500 
5,000 
174.000 N 
0 
Noddy Tern 
24 
10 
175 N 
Hawaiian Tern (Bryan, 1902, saw 20).. 
few 
100 
2,100 N 
2,500 N 
Fairy Tern 
fairly common 
1,000 
20,000 N 
increasing 
daily 
Domestic Pigeon 
0 
0 
50 N 
125 N 
Domestic Canary 
1,000 
1,000 
30 N 
75 N 
Laysan Finch 
abundant 
5,000 
0 
.0 
* N — indicates nesting on that date. 
