10 
Dark-rumped Petrel 
Three sightings were obtained on November 22 approximately 120 miles 
SW of the island of Kauai* 
Juan Fernandez Petrel 
This species was nearly five times as numerous outside the grid as 
within this month. Greatest densities were recorded between 163° and 168 ° 
above 20 • More than half of the 11;5 observed outside the grid were seen 
on November 21 in the middle of this area. An additional 28 Pterodroma 
externa recorded in this area were probably nearly all of this race. This 
concentration may have resulted from the storm in the area. Within the 
* 
grid, 2h were observed in the eastern half, only 6 in the western half. 
Most sightings were of 1-U birds though a few were seen in feeding flocks 
with terns. 
The northward movement of this species in fall seems to be correlated 
with the decline in the local Wedgetailed Shearwater populations, the 
Pterodroma seemingly moving into areas nearer the islands where the Wedge-tails 
are most numerous during their breeding season* The similarities in food 
requirements, morphology and feeding habits between the two groups suggest 
that competition between them could be a factor in this seasonal distribution, 
the less numerous Pterodromas being limited to areas of comparative low 
Wedge-tail density, then moving into the more food-rich areas closer to 
the islands as the Wedge-tails vacate them. 
White-necked Petrel 
Five were seen, all outside the grid, all but one north of 20° and one 
within 25 miles of Oahu. 
