) 
in delineating the range of the non-breeding population* 
Cne Juan Fernandez Petrel was collected in the grid this trip* 
rterodroma hypoleuca 
None of this species were identified as the subspecies hypoleuca . As was 
the case last year, there was a marked decrease in the density from November to 
December. This was most likely due to movement towards the breeding grounds, 
but may have also been due to the high December winds in both years. . (The 
sighting of three Bonin Island Fetrels north of Johnston on 6 December suggests 
that this species may be susceptible to being pushed from their "normal" range by 
high winds.) 
. 1 1 a* 
Unlike last month, the density distribution of P.h ypoleuca in the grid 
was not similar to P^ externa (see table 3). This change may also have been due 
to high December winds. 
One Black-winged Petrel was collected in the grid. 
Kermadec Petrel 
Both sightings of this species were in the western portion of the grid, 
and both were in mixed feeding flocks. 
VIhite-rumped storm petrels. 
Although all of the storm petrels were probably Leach 1 s, none were positively 
identified. Distribution appeared fairly random throughout all but the northern 
quadrant, where they were fairly scarce. 
White-tailed Tropicbird 
One bird was seen sitting on the water in the east quadrant. 
Red-tailed Tropicbird 
The large decrease since last month is not unexpected in view of the total 
absence of Red-tails in December last year. However it is possible (although 
unlikely) that in both years this species may have been affected by the high 
winds• 
This December survey suggested a total absence of Red-tails in the eastern 
half of the grid area, which follows the November density distribution. 
