ENDERBURY ISLAID 
DRAFT 2 
birds 
Red-footed Booby ( Sula sula ) : 
most abundant 
Current Status: Common resident .and^nesting species* 
FOBSP 
Spring' Aha gg a e r mammum. Rb-ximum/\pop’ulatlon estimate; 
• / 
1500 in July and November 1963, July^ 1964 # iiinimu E3F population estimate 
3 
500 in February, 1964* 
Trior Records: Cassin (1858) records that the Wilke; 
ion Ac odd Red¬ 
footed Boobies nesting on bushes in January, 184f>-. The nesos were built of 
sticks and some contained fresh eggs /Title others way occupied by young birds 
in all stages of growth. He states that two young or two eggs were rarely 
found in the same nest. P@BBF"p 7 si , ' r odnn - el' have neyOr~Mdxind^rTiest with two 
eggs in the T hoenix“and Lii 
.b JLC 
.s. Munro (kB 1938) 
found birds on eggs on July 26, 1938 and 0/ Hay 30 of the next year Kinney 
banded 200 o £■ -iso . 
Population: On five of the seven FOBS? 3 visits to Enderbury the Red-footed 
Booby population was estimated to be between 1100 and 1500 (see Appendix A). 
On the other two visits in February and November 1964 the 
estimated populations were respectively 500 and 800 birds. 
Jr 
Through June, 1965 a total of l60o adults ha?v«© had been banded and in Hay 
1965 approximately 50 percent of the birds handled were banded. This would 
indicate that a population of clout 3,000 Red-footed Boobies use the Island 
- 
annually. Only about half this total is on the island during any given day. 
Annual Cycle: Heat count data collected from July 1963 to November 19 64 
guZar annual cycle with a summer peak and a* considerably diminished- 
breeding activity in winter. In February 1965 many more nests were found than 
we would have expected from the previous data. About half of the 400 nests contain 
chicks which indicates that many birds must have laid eggs in December 1964# 
This nesting activity possibly indicates early initiation of the nesting 
cycle In 1965 or conversely may indie ate that environmental conditions 
