Varia%on(in(Breeding(Success(of(Red3billed(Tropicbirds((Phaethon(aethereus)(on(St.(Eusta%us(

SCSCB(Regional(Mee%ng,(27(–(31(July(2013(Hannah(Madden(

St.(Eusta%us(Na%onal(Parks((STENAPA)!

St.(Eusta%us((Sta%a)(

Sta%a:!'  11!sq!miles!' !Es%mate!+/'!300'500!pairs!of!RBTR!' !Together!with!Saba,!33'40%!of!global!RBTR!popula%on!

Saba!

Primary(Nes%ng(and(Study(Sites(

Zeelandia!

Pilot!Hill!

Pilot!Ridge!

Signal!Hill!

Crooks!Castle!

Ra%onale(

A(similar(study(conducted(on(Saba((2011)(resulted(in(the(discovery(of(high(levels((100%)(of(preda%on(at(one(nes%ng(site(

Status( TENT(Colony(

Eggs(laid( 39(

Eggs((probably)(hatched( 34(

Chicks(fledged( 0(

%(Breeding(Success( 0.00%(

Methods(

  Record!%ming!of!egg!laying!  !!Individually!marked!nests!and!adult!birds!  !!Status!of!nests!regularly!followed!  !!Chick!growth!and!development!recorded!  !!Fieldwork!supported!by!24'hour!infra'red!

cameras!  !Preliminary!predator!control!(rat!traps)!

Results(

Eggs(laid:!99!Eggs(hatched:!59!Not(yet(hatched:!4!Eggs(lost:!36!

0.0%!

10.0%!

20.0%!

30.0%!

40.0%!

50.0%!

60.0%!

70.0%!

80.0%!

90.0%!

100.0%!

Signal!Hill! Crooks!Castle! Zeelandia! Pilot!Hill! Pilot!Ridge! Total!

Hatching(Success(

Birds(banded:!146!Primary(and(secondary(nests:!197!Primary(nests:!85!

n=11! n=4! n=14! n=45! n=25! n=99!

Percen

t!Hatching!Success!

RBTR!Colonies!

(percentage!of!hatched!eggs!per!number!of!eggs)!!

Results(Chicks(apparently(fledged:!46!Dead(chicks:!2!(not!preda%on)!Fate(unknown:!11!

0.0%!

10.0%!

20.0%!

30.0%!

40.0%!

50.0%!

60.0%!

70.0%!

80.0%!

90.0%!

100.0%!

Signal!Hill! Crooks!Castle! Zeelandia! Pilot!Hill! Pilot!Ridge! Total!

Apparent(Fledging(Success(

n=11! n=4! n=14! n=45! n=25! n=99!

Percen

t!Fledging!Success!

RBTR!Colonies!

(%!fledged!chicks!per!number!of!hatched!eggs)!

Results(

0.0%!

10.0%!

20.0%!

30.0%!

40.0%!

50.0%!

60.0%!

70.0%!

80.0%!

90.0%!

100.0%!

Signal!Hill! Crooks!Castle! Zeelandia! Pilot!Hill! Pilot!Ridge! Total!

Apparent(Breeding(Success((

n=11! n=4! n=14! n=45! n=25! n=99!

Percen

t!Breed

ing!Success!

RBTR!Colonies!

(%!fledged!chicks!per!number!of!laid!eggs)!

0.0%!

10.0%!

20.0%!

30.0%!

40.0%!

50.0%!

60.0%!

70.0%!

80.0%!

90.0%!

100.0%!

%!Hatching!Success!! %!Fledging!Success!! %!Breeding!Success!

Apparent(Nes%ng(Success(

Signal!Hill!

Crooks!

Zeelandia!

Pilot!Hill!

Pilot!Ridge!

TOTAL!

Results(Percen

t!success!

Biological!Measure!

Saba,(2011(Percen

t!success!

Biological!Measure!!

0.0%!

10.0%!

20.0%!

30.0%!

40.0%!

50.0%!

60.0%!

70.0%!

80.0%!

90.0%!

100.0%!

%!Hatching!Success!! %!Fledging!Success!! %!Breeding!Success!

TENT!

OBH!

Overall/Total!

Egg(Loss/Chick(Mortality(

Evidence(of(Predators(

Future(Plans(

  !Inves%gate!egg!loss!at!one!site!(Pilot!Hill)!in!2014!!

  !Possible!diet!study!in!collabora%on!with!IMARES!(NL)!and!Science!Centre!(Sta%a)!

  !Long'term!monitoring!of!nest!fidelity!/!inter'island!movements!(Saba/Sta%a)!

  !RBTR!movements!'!geolocators!(Dr.!Pat!Jodice,!Clemson!University)!

  Con%nued!popula%on!and!produc%vity!monitoring!

Acknowledgements(

'!NFWF/SCSCB!!'!Intern!Andrew!Ellis!'!NuStar!'!Dutch!Caribbean!Nature!Alliance!(DCNA)!'!Dr.!Adrian!Delnevo,!Dr.!Pat!Jodice!&!Dr.!Will!Mackin!'!Jose'Luis!Garcia!and!Giovanni!Balensuela!

Ques%ons(