Blue-faced Pooby 
The numbers of this species remain essentially unchanged from last month. 
Unlike last month however, all the sightingsvere confined to the western hall 
of the grid. All were immatures. 
Red-footed Booby 
Following the pattern of November and December, 1969 there was an increase 
in numbers of this species in December this year# The ages of all the sighting^ 
included 16 immatures, 3 subadults(including one with an orange streamer), and 
only one adult. As mentioned in last month'd report, there is good evidence 
that there is an age-oriented behavior greatly influencing pelagic movements 
of this species. This is strikingly illustrated when this month’s grid age 
composition is compared to ages of birds in the non-grid .section of this cruise 
north of Johnston, On lli December at about 100 miles northeast of Johnston, 17 
Red-foots were aged. Of these, 11 were adults, 3 were subadults, and three were 
immatures. This is a direct reversal of whet was found south of the island in the 
grid area. It would seem possible that a young bird might learn the locations 
of good feeding areas by trial and error, and hence tend to wander much more than 
adults. This could explain their presence in the grid. 
Great Frigatebird 
The population densities in November and December of 196$ and 1966 were 
identical. In both years there was a considerable drop which would suggest 
some sort of seasonal movement, or more likely that the species is easily 
affected by high winds as postulated last year. 
Unlike November, the distribution within the grid this month seemed to be 
random with virtually even densities over the entire grid. No directional trend 
was observed. 1 
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4 “ «• ; »■■■-* 
Sooty Tern 
A total of 7h Sooties was identified during the diurnal survey this 
month; all but two were in two mixed feeding flocks. An additional 21 were 
heard or seen during nocturnal watches, with a majority (17) being noted on 
