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Fterodroma externa 
The largest concentrations of this species were encountered in the western 
quadrant of the grid* * Good numbers were also recorded in the other quadrants, 
tut with significantly lower numbers between 171 and 173 degrees west. The grid 
population size and distribution is quite different frem that found in Nov. l?f 
there being many more ?j_ externa this year. 
i 
Two subspecies (White-necked and Juan Fernandez Petrel) were recorded, 
v?ith the former being very scarce and only in the northwestern area of t\ r grid. 
Pterodroma hypoleuca 
The distribution of this species in the grid closely resembles that of 
P. e x terna. Like that species, the Black-winged Petrel was noticeably missing 
from the area between 171 and 173 degrees west. In the eastern areas of the grid 
both P. externa and hypoleuca were most frequently noted as single birds while 
in the western portions they were most frequently seen in mired feeding flocks. 
* 
This is most likely due to variations in concentrations of food. 
White-winded. Petrel ,|' 
Athdiigh th id -is ^usually an easily misidentified species, one observation 
of a n dark phase" bird in a mixed feeding flock on the 18th is quite certain. 
This observation was within 2C miles of the southernmost part of the grid. 
An additional sighting of three birds on 22 November was not accompanied 
by any description, and field marks later described did not fit P. leucoptera. 
Kenn a dec Petrel 
All four sightings of this species were in the western third of the grid, 
and all were in different feeding flocks. 
Phoenix Island and Tahitian Pet r el 
All sightings of both species were in the western portion of the ,rid f 
* 
Although the two are easily confused, one bird seen on the 23rd was believed 
to have been a Tahitian Petrel, 
Let*lrd Petrel 
