RED-TAILED TROPICBIRD 
Annotated List — p.3. 
LISIANSKI 
L£$ 18 Mar. $1^20, '67 (CDH Kept) Estimated population 
20+ ad.courting 
(CDH notes) About 20 birds in the. air over the island' 
courting. Only 2 birds observed on the ground. No eggs or chicks were 
found. 
LS/f 19 June 2-6, ' 6 7 (DLS Rept) Estimated population- 4,500 adults 
- Number of re sts 4—- 1 ,500 
Red-tailed Tropicbirds were common around the perimeter of the island, 
where Ipomea had grown over Scaevola giving a protected shady area fro 
nesting. Nests were scratched out: areas with Scaevola and Ipomea leaves 
being used for lining. Nests were also found in the interior whereever 
l° w light intensity was available. While banding Chris Thompson found 
50 birds on eggs, one small downy chick, two medium downy chicks, and 27 
birds with no young or egg. A minimum of 1,500 nests were on the island 
and possibly twice that number of adults. 
» 
(FCT) Total estimated population: 250. The majority of the breeding birds 
were on eggs and nesting in Scaevola on the beach margins. 3 or 4 medium 
to small chicks were noted. 80 individuals banded. Nests arranged about 
2-3 to a clump of Scaevola on the beach. 
LS# 21 Aug. 31- Sept.5, '67 (KBC-CAE Rept.) 
v ' ' * - * 
.<<■»> •• *- j 
■ Y . v 4 • r y'v 
Red-tailed Tropicbird Peculation estimate - 800 (adults) 
* ^ ^ .v r Sample nest count results: (128 nests) 
Nests/egg-~— - 4 (3$) 
« m* J" ' 1 • • ’ r ' 
.> * * ' ‘ 4 
Nests/small downy young-* 16 (13$) 
Nests/medium sized or large downy 
young...—. 50 ( 39 %) 
Nests/dependent immatures —*—-— 58 (45$) 
Banded-—*— --—»—■—— 58 (adults) 
■--—■—“— -—— -— 108 (young) 
-------- 16 ^ (total 
Returned -—■——~— -2 (adults) 
Red-tailed Tropicbirds' could be found in most parts of the island but 
* they exhibited distinct tendencies towards denser numbers in some areas» 
Considerably higher densities of nesting birds were found in the Scaevola 
of the northeast and north perimeters and in the Scaevola behind camp on 
• -the east side of the island. Individuals were found nesting in the center 
of the island under thick Ipomea — growth so dense that a nest would not 
be found unless the tropicbird called out when disturbed. 
* 
This species was often chased by female frigatebirds but none of the 
dozen or so chases observed was successful (from the frigatebird’s point 
of view). This may be because the tropicbird 1 s defense in such chases 
was to climb higher and higher in the air apparently escaping the frigate- 
birds through better climbing ability (though tropicbirds in level flight 
_ did not seem capable of as great a speed as the frigatebirds.) 
Numbers of tropicbirds flying over the island in "courtship display" 
seemed pronouncedly greater during the middle of the day. 
