Blue-faced Booby (Sula dactylatra) 
Current Status : Common resident and fifth most abundant breeding species 
*4mximum ]POBS Pj population estimate; 2000 in November, 1964 
population estimate: 400 in February,1964. 
* * 
Frior Records : Cass 1 ( 1858 ) reported that the Blue-faced Booby was abundant 
on Honden and Enderbury Islands and that they were "sitting and hatching" 
in January l84l. Monro noted that the species was common' 
1^1 
in July ? 1938 and in the-ispring-James E. A. Kinney 
banded I 50 adults between April 2 and May 15* 
Population : The Blue-faced Booby population^/ on Enderbury fluctuate^con¬ 
siderably throughout the year. The largest populations are present well 
after the breeding peak but the smallest populations are associated with 
- 
little or no nesting activity. 
A considerable proportion of the island population consists of non¬ 
breeding birds as is shown in Table 
below. 
Table _Variation in composition of the Blue-faced Booby Populations 
on Enderbury 
Number of 
Number of Non- 
Percent of 
Nesting Birds* 
nesting Birds 
Population nesting 
July 1963 
790 
1100 
42 
November 1963 
200 
1500 
12 
February 1964 
400 
00 
July 1964 
850 
750 
53 
November 1964 
620 
1400 
31 
February 1965 
4o 
750 
o4 
May 1965 
150 
550 
21 
Oc\oY>s.n~* 
*4*©^ (c>c> 
£ 
0 ^ 
^he~lrumber of nesting birds is based on an actual count of the nests 
with less than one percent error. The number of non-nesting birds is 
an estimate made from the number of birds banded but is probably accurate 
to within 10 percent ,.________ ______ 
The breeding population in both 1963 and 1964 das at least 1,000 and 
probably closer to 1,250 (see Appendix A). Over 2,700 adult and 350 subadult 
#18/5 OeWoev* 
birds bave been banded on the island from July 1963 through * 
Lincoln index" ealeuljrfcieH- based-oir-May lyo;? recapttnw~hrd±^^ 
an4-4y0OO^~ 
between-3 5 -0Qa„^ 
