At Sea Observations, First Half 
General Summary SIC 9 
The first half of SIC9 can be divided into three sections; the nine days 
between Oahu and Howland Island via Johnston Atoll, the five days within 
100 miles of Howland and Baker Island,?, and the eight days in the Phoenix 
Islands and on the way to American Samoa. 
Sooty Terns dominated the first section. There were numerous flocks, 
many of which contained wintering southern hemisphere petrels. Four¬ 
teen oranged streamered birds of five species were seen, all but three 
within 50 miles of Johnston Atoll. The other three were between Johnston 
and Oahu. 
Numbers were highest xn the Howland-Baker area. This was the result 
both of a peak of migration of Sooty and/or Slender-billed Shearwaters and 
of large numbers of Sooty Terns feeding in the general area. The shearwater 
migration was of an intensity not previously encountered in the Central 
Pacific* For several hours on 16 September birds were streaming past the 
ship in excess of 150 birds per minute, resulting in an all day average of 
450 birds per mile. The migration peak occurred between 14 and 16 September 
and again on 19 and 20 September. During these days a majority of birds 
observed clearly had dark underwings, while on days before and after the 
peak birds with silver underwings predominated. The feeding flocks 
encountered in this area were large, but feeding was erratic so that most 
flocks were continually dispersing and reforming elsewhere, preventing 
entry into the flocks for collecting purposes. 
The third section was characterized by fewer birds than were recorded in 
the first two sections. Procellariids were very low in numbers. Flocks 
were less frequently observed, and contained fewer birds. One immense 
mixed feeding flock was encountered two miles from Enderbery Island which 
contained 4000 birds feeding over an area of many acres. It was com¬ 
posed mainly of Sooty and Hawaiian Noddy Terns, frigates, and all three 
species of boobies. 
At least 36 species of seabirds were recorded on the cruise. Forty-two 
birds of nine species were collected. Unusual sightings inculuded one Pale¬ 
footed Shearwater, one Dark-rumped Petrel, one Mottled Petrel, and 19 
Jaegers and a Skua. 
Warren B. King 
Research Asst. 
Pacif:* c Project 
