avifauna more similar to the primative condition. 
,S1X 
Of the ei :ht common nest in-: species (Red-tailed Tropicbird, 
Annual Cycle: 
Blue-faced Booby, Red-footed Booby, Great Frigatobird, Lesser F'rigatebird 
and Gray-backed Tern) ajsg &g - have annual peaks of reproductive activity and one 
(Sooty Tern) apparently nests every six months and one (Brown Booby) docs not 
seem to exhibit any particular choice of breeding se son. All six of the former 
tJ X 
species have a spring or summer nesting peak and the Sooty Tern has peaks in 
January and - June. Some individuals n :st£ in almost ever; month of the year 
despite the choice of breeding seasons 
■On Howland Island the period from July 1963 to February 19 64 was unfavorable 
for nesting 
(Sibley and Clapp, in prep) and nesting success was very 
low. 
ii. 
similar situation was found on Jl.derbury Island during this period although it does 
not appear to have been as prolonged. 
Table 
compared the number of nests j 
£ 
compared with nesting .ctivity in presumably more 
during this period 
Ct v c- 'f<st fy ! C 
months of 1963 and 1964 
