migrating shearwaters passing through the central Pacific in fall are Sooty 
Shearwaters. However, since the grid was not surveyed during September and 
October, it is possible that larger numbers of that species were present there 
then. 
Nearly 100^ of the birds observed were flying due south. As the birds 
increased in numbers so did the numbers of flocks, ranging in size from 5 
•to birds with an average of about lU. Many of the flocks spent much 
time milling about along their flight path, indicating that they might be 
young birds and that the young pass through the area primarily at the end 
of the migration period. 
Approximately equal numbers of this species were seen within and 
outside the grid. However, the birds were far from evenly distributed, 
more than 2000 of the total of 275k being observed on 17 and 18 November. 
Another smaller concentration was encountered on Novanber 10-12, accounting 
for 359 of the remainder. Each of these areas was partially within the grid. 
Thus, of the total of U;77 present in the grid, 1269 were recorded on the 
westernmost leg November 17, while low numbers were obtained on the inner 
four legs. 
There thus appears to be a general gradient of increasing numbers from 
east to west, which is consistent with the even higher numbers recorded in 
the Howland-Baker area in September and October. Approximately equal numbers 
of birds were recorded between 167° and 170° over a week's interval. However, 
the large numbers of birds observed on the 17th and l8th were directly north 
of areas which had very few birds only one or two days previously. Therefore, 
the apparent local fluctuations and perhaps even the apparent gradient may 
