SULA LEUCOGASTER 



MARCH 1964 -JUNE 1965 



lit **» 



• Ibird 



• 5 birds 



• 25 birds 



Figure 19. — Distribution of Brown Booby. 



Brown Booby 



Sula leucogaster Boddaert 



The number of Brown Boobies recorded In 

 any given month depended more on the number 

 of hours of observation within 50 miles of Oahu 

 than on the relative seasonal abundance of the 

 bird. It is present year round on its breeding 

 grounds, the nearest of which to the study area 

 is Moku Manu, offshore Oahu (Richardson and 

 Fisher, 1950); no determination of population 

 peaks in the study area was possible. 



Distribution ; As can clearly be seen in figure 

 19, Brown Boobies tended to stay very close to 

 their breeding grounds. Of 81 birds observed, 

 all but 7 were within 50 miles of Oahu. The 

 other seven were scattered throughout the 

 southern third of the area. Birds were seen 

 away from Oahu only in October 1964 and Feb- 

 ruary and March 1965. 



Red-footed Booby 

 Sula sula Linnaeus 



Status: Locally abundant resident. 



Months 



Year 



1964 



1965 



Since monthly fluctuations in recorded num- 

 bers of Red-footed Boobies in the study area 

 probably reflected the number of hours of day- 

 light, and hence of observations, near Oahu 

 (where the species breeds), rather than actual 

 seasonal increases and decreases, I did not 

 attempt to determine population peaks. 



Distribution : Only 22 of 1,082 Red-footed 

 Boobies (1.9 percent) were found more than 50 

 miles from Oahu (fig. 20). Of these 22, 11 were 

 immatures and 4 were adults (no age data for 

 7). All four adults were seen north of Oahu. 

 The immature birds were spread at random 

 through the area. Most birds seen near Oahu 

 were adults. 



k6 



