- ENDERBU EY DRAFT 2 
CXlA'CV'M^' olA-e Ov6t"T 
AND m.VE MADE 01R ESTIMATES OF THIS BASIS, 
DTfl'nq 
iJjU 
Table 
Red-tailed Tropicbird nest ce-cle on Enderbury 
February 
6 ( 100 $) 
9(86$g) 
May July 
325 ( 47 $) 
436 ( 61 $) 
240(56$) 
November 
26 (6 %) 
75 ( 00 %) 
The first figure represents the estimated numbers of nests with 
/ 
the second the proportion of nests found confining Aggs p 
The first eggs are laid in January or February as indicated by the two 
February counts given above but the peak of laying i from ■' 1 (ytHrrtoiJur 
‘ , / 
through June* In November of 1963 and 1964 /there were still a number of large 
;■ oung present which must have hatched fjom eggs laid about 75 days before, 
perhaps in early August. 
The annual cycle.;f In this speq4.es is apparently less variablethan in most 
other species breeding i "the cenl/ap Pacific 
There also seems to be a more 
IV* 
vnC *=> ^ 
gradual increase and decrease pci nesting activity than in most other species. 
/ occur ed 
However the laying peak in 1964 must haveAsomewhat later than In 1963 since 
a significantly larger (i s f ■«12 t 9 ) proportions of the neats contained eggs in y 
/ 
1964 . 
Reproduction: The bipds nest in a variety of habitats on the island and are 
concentrated In areas favorable for nest siteJ^ Along the west side and trr**r 
laso or cgfreirte on the /south and east sides ihe Red-teiled Tropicbirds nest under 
J % 
slabs of coral. The heaviest concentration in this habitat is several hundred 
yards north of the lighthouse. The 3 ^ also nest around the remains of the colonjml 
* * 
\ri 
installations under old drums, wreckage and the house. 
In the interior of the island alternating layers of (yard ana soft guano 
rock have been exposed :he edges of the old guano diggings, feathering has 
produced uneven wear on the different layers an - 1 lec e has been 
tin 
