11 . 
Very few of the birds appeared to be migrating, indicating that this 
area is a part of the wintering range of this species (see figure 16 )- 
Pomarine Jaeger ( Stercorarius pomarinus ) 
Long-tailed Jaeger ( Ster corarius longicaudus ) 
These two species of .jaegers were identified, but I do not feel 
at all confident in separating the three jaegers in the field and it 
is very likely that the Parasitic Jaeger also occurred in this area 
and went unnoticed or misidentified. 
Jaegers were scattered over the whole area, which is evidently 
a wintering area for the group (see figure 17 )• 
Sooty Tern ( Sterna fuscata ) 
Sooty Terns were by far the most abundant bird in the study area, 
accounting for 59*05$ of* the total population. They were found mainly 
between 15°N and 15°S (see figure l8). The distribution along the 119th 
meridian was very different from the distribution along the 126 th meridian. 
On the eastern leg abundance was bimodal with a peak at 10°N and 7~15°S. 
However, along the western leg they were abundant from about 13°S to 
7°N with a small gap along the equator. 
The origin of these birds remains obscure but there are a few 
relevant points. First of all, immature or subadult birds were seen 
throughout the area indicating that the birds in the area were post- 
nesters from the fall nesting season. Secondly, out of fourteen 
traveling flocks, (north and south of the equator) 13 were headed east, 
while the other one was headed west. And finally, 27 of 28 frigatebirds 
were found south of the equator associated with the Sooty Tern flocks. 
The fact that the flocks were headed east would indicate that the 
birds were from the west Le., Marquesas and Line Islands. These island 
groups also have a fall breeding cycle which would account for 
