WEDGE-TAIL SHEARWATER ( Puffirms pacificus ): At-Sea Distribution and Abundance 
The following maps represent all At-Sea observations made by 
personnel of the Pacific Ocean Biological Survey Program from February, 
1963, through August, 1965. 
Each square represents one days observation from the first through 
the fifteenth of the month, while each circle represents one days 
observation from the sixteenth through the thirty-first of each month. 
Numbers refer to number of birds per observation hour (* = less 
than 00.5 birds per hour). On the average each hours observation represents 
ten linear ship miles of observation. 
birds per hour 
n TT IT 
tr tt 11 
Tt T» ft 
tr tt tt 
A single black line, running from east to west represents the 
northward extension of the southern dark-phase population of this 
o % 
species. 
Color code: 
= 0 
= *-10 
-V = 11-50 
= 51 -100 
= 100 + 
