(Wedge-tailed Shearwater) 
3 
Gould, P. J. 
The ship was moving at a fairly constant speed of 8.5 knots between these 
observations . 
//Theory// 
A shearwater flying ca. 5’ above the water can probably detect another bird 
the same height above the water at about 5 miles range. Shearwaters wander about 
the ocean singly or in groups of 2—4- in a normal and stable hunting flight pattern. 
When they come upon a food source their behavior changes faster flying, more up 
and down soaring, etc. This attracts other birds to the food source. Other birds 
should be attracted from as far away as they can see the feeding bird-- (at least 5 
miles by the above figuring and since they get higher than 5’ on occasion this 
observation distance should be greater. 
The above data shows that no birds were seen 38 minutes before the flock was 
reached or ca. 60 minutes after the flock nad passed (since this flock was near si^ip 
for ca. 5 min. ) . 
At 8.5 knots this means that there were no birds on either side of the flock 
(in two directions at least) for 8.5 miles on one side and ca. 5-^ miles on the 
other. 
So this might indicate effective dispersal capacity for the birds and if the 
birds used it to perfection there should be 1 bird per area= =a circle 
with a 5 mile radius. (Roughly this would mean that the birds could effectively 
utilize the area with 1 bird every 5 miles. "If birds were at maximum deployment 
then only 5 birds could probably utilize each food source." 
September 6--2nd day out Oahu, Hawaiian Is., Pacific Ocean 
Watching these and other shearwaters and Petrels today it appears that a 
majority are following along the path of the wavetroughs. 
They appear to change troughs frequently to preserve a straight course (always 
