MOTTLED PETREL coat. 
total of 12 was recorded last month, of which 3 were collected during noctur¬ 
nal operations. Two sightings of unidentified Pterodroma during the present 
cruise may have been of this species# 
BULKER'S PETREL (1) 
Normally recorded in low numbers, an abundance of migrating birds noted 
in March, with lesser numbers in April. These migrating birds were moving 
through the grid in E-SE direction, most likely to the Line or Phoenix Islands. 
« 
% 
WHITE-THROATED STORM PETREL (1) 
The few records of this species in the grid are likely from breeding popula¬ 
tions in the Phoenix Islands. The species has not been recorded in the grid 
since last fall. 
LEACH'S STORM PETREL (2+1 nocturnal) 
KAR COURT'S STORM PETREL (5) 
WHITE-RUMPED STORM PETRELS (81 + 3 nocturnal) 
Numbers of storm petrels are down considerably from last month. This was ex¬ 
pected with the advent of northward spring migration of Leach's Storm Petrels, 
the dominant grid species. Harcourt's Storm Petrel has been recorded in very 
low numbers since last fall. Probably the majority of the 84 unidentified 
storm petrels are referable to Leach's. 
RED-TAILED TROPICSIRD (1) 
Recorded in low numbers on all cruises to date. The few birds which breed on 
Howland can be expected to occur in the grid avifauna. 
BLUE-FACED BOOBY (225 + 1 nocturnal) 
This species was over twice as abundant as last month. Two peak days occurred: 
on 3 May when all operations were carried on between Howland and Baker, and on 
