Comparative Breeding Data --Laysan and Lisianski 
Date of 
Survey 
Population and Breeding 
Data Laysan 
Population and Breeding 
Data--Lisianski 
Relationship of Lisi¬ 
anski cycle to Laysan 
Red-tailed Tropicbird 
mid 
March - 7~10 No nests found 
1965 
mid 
July 2000 Partially inc. eggs 
1965 to fledging young, ca. 
l /2 nests with young?? 
20-30 One nest/egg 
1000 Partially inc.eggs 
to near-fledging young 
ca .200 young. Scn :60 
5 $ e, 7 $ sdy, k 2 % mdy 
to Idy, h 7 $ dep. imm. 
Very slightly earlier 
or the same 
Rot clearly different 
1965 summary -Same as Laysan or possibly very slightly earlier 
initiation of nesting 
mid 
June 
I.966 
1000 ®st-. 400 nests^g 
snc:n:90--98$ e, 
1 $ sdy, 1$ ly 
600 est. 300 nests 
ca. 50$ ©5 ca. 50$ Yg 
If egg young ratio 
for Lisianski not 
pie in the sky than 
week or so earlier 
mid 
Oct 
1966 
50 Sev. nr.flging yg. 
Do e or small yg. 
25 0s, 10 nr.flg.yg. 
Do e or sy 
Same or possibly 
earlier finish if 
pop. ests. reliable 
1966 summary -- Data suggests initiation and termination of Lisianski cycle somewhat 
earlier. 
mid 
March 
1967 
50, sev. n/e 
25? no nests found, no 
special search made 
Rot clearly differeif . 
If pop. ests. OK, 
possibly slightly later 
early 
June 
1967 
kOOO est. 1000 nests 
sncn: 87: 79/0 e, 18 $ 
sdy, 3$ tfidy & Idy. 
4500 , est. 1500 nests 
sncn: 53: 9^$ e, 2$ sdy, 
k $ mdy 
Somewhat later, a week 
difference in egg peak?? 
early 
Sept 
1967 
1500 less than 5$ e, 
ca. 5$ sdy, 10$ mdy or 
Idy, 85$ dep.imm. 
800, sncn: 128: 3$ rhyg, 
13$ sdy, 39$ mdy or ldy, 
h5$ dep. imm. 
Suggests overall season 
terminating later, but 
nesting on Laysan would 
continue longer. 
1967 summary -- Data suggest somewhat 
Lisianski 
later peak periods of laying andfledging on 
mid 
March 
1968 
100 , no nests found 
100 , 2 n/e 
Rot clearly different 
1968 summary -- Data insnggicient, indicate no difference as far as they go 
early 
March 
1961 
A few seen flying 
many 
Pop.,, weak data 
suggests slightly 
earlier 
1961 summary -- Data insufficient, possibly earlier but datq, poor. 
Overall conclusion vis a vis Laysan : Similar, apparently si 
i 
earlier (1966) or later (1967) in some seasons. 
