PRELIMINARY REPORT AT-SEA SURVEY 
April 1966 
SMITHSONIAN GRID # I ONLY 
The following brief report covers the observations and collections made 
within the Smithsonian Grid # I area during the period 2-3 April 1966. POBSP 
personnel assigned to SIC 12 aboard the U.S.N.S. SHEARVJATER (TAG-177) entered 
the grid at 0418, 2 April at position 15^-40 N; 170°-04 VJ and departed at 
0055, 3 April at position 12 0 -27 l ; I7l°-33 f W. Diurnal observations were made 
from sunrise to sunset on 2 April and nocturnal operations were held from time 
of entry into the grid until time of departure. 
The number of birds recorded in the grid during diurnal observations on 
2 April was much lower than that recorded during 1 April to the east and north¬ 
east of Johnston Atoll. During 1 April, 1,439 birds were recorded; throughout 
2 April in the grid, only 242 were recorded. Although the close proximity of 
Johnston Atoll during the 1 April observations unbalances the comparison, there 
were unquestionably greater densities of feeding birds present to the east and 
northeast of Johnston than south of it in the grid area. Large numbers of Red- 
i 
footed Boobies and Greater Frigatebirds were observed east and northeast of John¬ 
ston, whereas these species were practically absent from the grid. 
Sooty Terns were dominant during both diurnal and nocturnal observations within 
the grid area. This species accounted for over 54 7. of the total diurnal birds 
recorded, and 90 7. of the nocturnal total. Sooty/Slender-billed Shearwaters 
were the second most abundant species. The tern and shearwater-petrel groups 
together accounted for roughly 96 7. of total birds. 
