- 8 - 
in the group for November, a 62 % decrease in density occurred. 
The reasons for this unexpected decrease are unknown at present* 
Red-tailed Tropicbird (6+1 nocturnal) 
Low density comparable to that of November-December 1965 was noted 
during the present cruise* Higher numbers have been recorded con¬ 
sistently during the breeding season on Howland from July through 
October 1966* A high percentage of the birds utilizing the grid, 
however, are from other areas as 6hown by collection of banded 
♦ 
i 
birds* Only three such birds have been collected at sea, all in 
• * 
the Southern Grid, and respectively from Jarvis Island, Christmas 
Island and Enderbury Island, v 
Blue-faced Booby (285 + 6 nocturnal) 
Density rose from 0,26 during October 1966 to 0,70 during the pres- 
% 
ent cruise. This is considered to be primarily the result of in- 
creased cruise activity in the vicinity of the islands, and in part 
to a buildup in the breeding population on Howland* The majority 
of sightings were within 10 miles of Howland. A total of 15 How¬ 
land blue-strearnered birds were recorded during "the cruise, at dis¬ 
tances of up to 20 miles from Howland* The majority of these were 
immature birds which are greatly attracted to the ship* 
i 
Brown Booby (9) 
* 
Numbers of this species are consistently, low and correspond to the 
small stable population on Howland. As suggested in previous re¬ 
ports, fluctuation in number of sightings are usually the result 
I 
i 
of increased or decreased cruise activity near the islands* 
* 
I 
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