2 
SPLCIES ACCOUNTS 
1; edg e- tailed Shearwater 
The abundance of Wedgetails in the North and Vest quadrants of the b rid 
is in keeping with the comparative abundance of other species. But when 
compared with the November 196$ northern grid survey, they were surprisingly 
numerous. Last year no Wedgetails were seen in November in the grid, whereas 
this November 135 were identified. None of these were suspected of being young 
birds which are readily identified (in the north) if within a month or two of 
fledging;. 
That this specie’s should vary in numbers from year to year (and month, to 
month) probably reflects the abundance of food rather than seasonal direction 
movements. If directional movement occurred, it would seem probable that it 
would be reflected in the directions of flights recorded with each observation. 
Analysis of this year's data suggests no directional trends, nor do the data 
from previous years suggest migration patterns, 
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Christmas Island Shearwater 
Two individuals were noted as single birds. Although this species mijr.t 
be confused with thf Sooty Shearwater, both identifications were quite certain. 
Sooty and Slender-billed Shearwater 
These two species are difficult to separate at long distances; however, 
if an experienced observer is alert they may be identified at a relatively 
close range. Most personnel on this cruise were familiar with the two species, 
and specific identifications are considered reliable when given. 
There is no doubt of the fact that both species were migratin. through 
the grid this month. But the proportion is difficult to pin down due to the great 
variation from day to day, and even hour to hour. In addition, when a mixed 
flock passes by it is all tut impossible to determine how many of each species 
were present due to their fast flight and the relatively long time required 
for exact identification of each individual. However, during this survey it 
was established that both homogenous and mixed flocks occurred, and that 
