area, but not as marked as was observed in September* Part of 
the active area was crossed at night. Terns were notably inconspicuous 
from 8 N to Oahu* Pterodroma however, were very conspicuous 
between Johnston Atoll and Oahu, and many were observed in Moderately 
large (ca. 50) feeding flocks. 
FLOCKS : Since over 2/3 (67*1$) of non-grid observations were of birds in 
flocks, special attention was given to an analysis of flock data* Flocks 
are considered here as 5 or more birds acting more or less as a unit. Flocks 
are divided into 3 catagories; Feeding, Searching and Traveling, the somewhat 
arbitrary divisions being left to the discretion of the team on watch. 
Of 11U* flocks recorded 81 (56 %) were "Feeding" flocks, h2 (29%) "Searching" 
and 21 (. 9 %) "Traveling" blocks. Respectively the average sixe of each category 
is hi) y and lp birds each* Except where migrating birds are involved, feeding, 
searching, and traveling flocks are all involved in some phase of feeding; 
congregation or dispersion to or from a food source. The relative flock size 
of the three artificial groupings reflect this tendency. A useful piece of 
data which I feel should be investigated more regularly in future observations 
is flocks/linear mile; flock density (see Table #10). See Tables # 7 and 8 
for fii^her flock data. 
