3 
♦ 
Christmas Islan d Shearwater 
A 5inf le bird was seen on the 9th travelling northwest. 
Ncdge-tr.iled Shearwater 
The total count this December is identical to that last year, but the 
density is only about half as large. 
Compared to last month (135 identified) the population is surprisingly 
low. Whether it was high winds, the exodus of food, or some other factor that 
was responsible for the reduction is not explained. 
In comparing November's data, it seems possible that a post-breeding pop¬ 
ulation from the Hawaiian Islands was present in the grid during *Wember. Reasons 
for this hypothesis are based on very little data. First, it would seem quite 
probable that if the November Wedgetails were from Johnston, orange streamers 
would have been sighted. Secondly it is suggested that the Wedgetails were from 
: \ 'jfi 
a post-1 reeding population because of data collected this month. In November 
no immature Wedgetails were identified; but this month six of seven birds aged 
were identified as immatures. As adults leave the breeding islands before 
the young are able to fly , it would be expected that they would be present in 
the grid area before the immatures. Although the evidence is sparse, this 
possibility is suggested. 
As would be expected, the grid population of Wedgetails was largest in the 
« 
north and west quadrants. This follows the pattern of last month and last year. 
Dark-rumped Petrel 
One bird was seen on the 12th sitting on the water with two Juan Fernan¬ 
dez Petrels. 
Pterodrona externa 
As was the case last year, there was little significant change in the density 
im November and December. But there still remains a considerably higher number 
present than either November or December of 19&5# This fact combined with the 
month-to-month variation would suggest that some ecological factor is important 
