Wedge-tailed Shearwater (Puffinus pacificus) 
k light and 1 dark phase 
collected 
The distribution of this species was quite interesting, especially 
when compared to that of the Pterodroma (see maps 5 and 8). Perhaps more 
interesting, however, are the changes in color phase ratios on tracks 
transversed by the R/V UNDAUNTED in August-September and the R/V DSJ in 
October-November. In late August dark phase birds comprised 9 6 percent 
(M=132) of the birds along 105°W and 85 percent along 98°W. In November 
the light phase population was predominant by 8.5:1 in equivalent sections 
of the track. This change of color phase ratio clearly suggests that there 
are two Wedgetail populations in the Eastropac area at some times of the 
year, and that one of these populations had left the area by October- 
November. In other Eastropac reports it has been suggested that many of 
the Wedgetails in the survey area are from the Hawaiian group; the infor¬ 
mation from this cruise further substantiates this hypothesis. Slight 
additional suggestion may be found from the few specimens of Wedgetails 
which were collected during this cruise. As the Hawaiian population is 
now breeding we would expect that any remaining in the eastern area during 
October-November would be subadults or nonbreeding birds. This is what 
was noted in the five specimens collected. 
The distribution of Wedgetails in the survey area (see tables 2 and 
3 ) suggested that the October-November population favored the eastern portion 
of the North Equatorial Countercurrent with none being recorded below the 
southern boundary and only one north of the boundary in pelagic portions 
of the track. A few additional birds were seen within 500 miles of the 
Mexican coast. 
Pale-footed Shearwater ( Puffinus creotopus ) 
Pale-foots were rarely seen in pelagic waters. Along the coast they 
were seen uncommonly except off northern Baja where they were common. 
Christmas Shearwater ( Puffinus nativitatis ) 
A single bird travelling southwest was seen at the edge of a rain 
squall on the fourteenth of November, along 98°W. 
Common Shearwater ( Puffinus puffinus ) 
What were believed to have been two subspecies were seen during the 
course of the cruise. Most abundant was P.£. opisthalemas which was seen 
by the thousands off the northern Baja coast. What was believed to have 
been another subspecies was seen along the Mexican coast and at the mouth 
of the Gulf of California. It was the writer T s impression that these 
birds were much blacker on the back than their northern counterpart 
s. 
Farther to sea the Common Shearwater was rare. Their subspecific 
identification should remain open to question as it is possible some 
could be Newell’s Shearwater from the Hawaiian Islands. 
