Hihi(Stitchbird)Breedingon
Tiritiri
MatangiIsland
2015–2016BreedingSeason
MhairiMcCready1&JohnG.Ewen1,2
1)
2)
InstituteofZoology,ZoologicalSocietyofLondon,RegentsPark,NW14RY,London,UnitedKingdom.
Contactemail:john.ewen@ioz.ac.uk
©MhairiMcCready
Suggestedcitation:
McCreadyM.andEwenJ.G.2015.Hihi(Stitchbird)BreedingonTiritiriMatangiIsland:2015-2016
BreedingSeason.InternalReport.DepartmentofConservation,NewZealand.
Note:ThereisadataembargoinplacesopleasecontactJohnEwenpriortousingdatareported.
1. Summary
1.1Keyresultsforthecurrentyear
ThisseasonhasseenafurtherdeclineinthenumbersofhihionTiritiriwiththepre-breedingcensusproviding
numbersaslowasthosein2004.Productivityhoweverwashigherthanthepreviousseasonandnumbersof
fledglingsproducedperfemalewasthehighestforthelast5years.Onthecontrarytothisthepercentagehatching
successwasatanall-timelow.
129and141individualswererecordedintheSeptember2015andFebruary2016censusesrespectively.Thefirstegg
th
th
waslaidon20 September2015andthelastchickfledgedon15 March2016,thiswasalongandextendedbreeding
season.
Table1NumberoffemalesbreedinginthepopulationonTiritiriMatangi
Firstyearfemales
Olderfemales
SeeninSeptembersurvey
9
29
Breedingthisseason
13
40
Fledglingsproduced
18
112
1.2Pit-tagging
Theapplicationofpittagshascontinuedthisyear;theyareembeddedinplasticcolourbandswhichareslightlylonger
thanthosetraditionallyused.Thesebandsactasuniqueidentifiersfortheirbearers,whichcanbereadwirelesslybya
dataloggermounted,forexample,onafeeder.Thistechnologywouldallowforricherandmoreaccuratepopulation
data,amongstotherpossibilities.
Allbuttwooftheadultmalepopulationhavebeentaggedashaveallofthejuvenilesfromthisseason.Allofthetags
havebeenappliedintheabovemetalposition.Therehavebeenslippagesoverthemetalandintwocasesdownonto
thefoot.Theseslippageswerefromtagsthathavenotbeenweldedandworkcontinuestocatchallbirdsandweld
theirpittagsandcolourbands.Theremaybeanoptiontomovetoasmallerpittagsizetofurtherreducetheriskof
slippages.
2. Introduction
2.1Background
Thehihi,orstitchbird(Notiomystiscincta),isanendemicforest-dwellingpasserinethatwasoncefoundthroughout
thenorthisland.Thespeciesdeclinedrapidlyinthelate1800sduetoalossofhabitat,introducedpredators,and
possiblydisease.Theonlyremainingnaturallyoccurringpopulationisonlittlebarrierisland.Inaddition,therearefive
translocatedpopulationsmaintainedonTiritiriMatangiIsland,KapitiIsland,KarorisanctuaryinWellington,
MaungatautarinearHamilton,andBushyParknearWhanganui.
Hihiaresexuallydimorphic,territorialcavitynesterswithamatingsystemcharacterizedbyextra-pairandforced
copulations.TheybreedbetweenSeptemberandMarch,averagingtwoclutchesof4-5eggseach.Hihiforagefor
nectar,fruitandinsectsandtranslocatedpopulationsrelyheavilyonprovisionedsugarwaterintimesofscarcity.
2.2Sitedescription
TiritiriMatangiisa220hectareislandroughly3kilometreslongandonekilometrewide.ItislocatedintheHauraki
Gulf,28kilometresnorthofdowntownAuckland.Extensivelyfarmedinthe1900’s,Tirihasbeenreplantedwithover
280,000treessince1984inanattempttorecreatetheoriginalnorthernbroadleafcoastalforest.
TheremnantmatureforestonTiritiritiMatangiisdominatedbykohekohe,taraireandpohutakawa.Otherspecieson
theislandinclude:taupata,karamu,hangehange,mahoe,mapou,whau,ngaio,puriri,totara,rewarewa,hoheria,
hinau,pigeonwood,kowhai,karo,akeake,manuka,kanuka,kawakawa,fivefinger,houpara,wharangi,rangiora,
cottonwood,mingimingi,taurepo,nativebroom,koromiko,kumarahou,astelia,flax,muehlenbeckia,nativejasmine,
supplejack,andtreeferns.
TiritiriMatangiisfreefromintroducedpredators,althoughthereareseveralpairsofmorepork(Ninox
novaeseelandiae)andtheyareknowntoeathihi.Twospeciesofhoneyeater,tui(Prosthemaderanovaeseelandiae)
andbellbird(Anthornismelanura),occurnaturallyonTiriandcompetewiththehihiforfood.Aggressivebellbirds
regularlydisplacehihiatthesugarfeeders.Tui,however,areexcludedfromthefeedercagesbyvirtueoftheirlarger
size.
2.3Personnel
The2015-16breedingseasononTiritiriIslandwasmanagedandmonitoredbyMhairiMcCready.VictoriaFrankswas
continuingherPhDfieldworkandwasherethroughoutthebreedingseason.
Volunteersthisseasonwere:ChristineFriis,KateLee,KerynMcCrackenandEmilieVergauwe.Volunteerhelpis
alwaysusefulandappreciated.Allvolunteerswerecompetentinthetaskssetforthem.Thesevolunteerswere
organisedbyMhairiMcCreadyandDaveJenkins(islandranger),asthenormalroutethroughDOCwasnotworking.
Unfortunatelythismeantthevolunteersarrivedlateintheseasonafterthebusiestbreedingtimewheretheycould
havebeenagreaterhelpandhadamorecompleteexperience.
3. Methods
3.1Surveys
Apre-breedingsurveyandapost-breedingsurveywereconductedattheendofSeptember2015andFebruary2016.
Eachoftheseinvolvedapproximately40person-hoursspentrecordingbandcombinationsofbirdsfoundthroughout
bushpatchesandatsugarfeeders.Aless-experiencedvolunteerwasenlistedfortheFebruarysurvey.Atrialof
recordingbirdsusingtheirpittags,antennaanddataloggerssituatedatsugarfeederswascarriedoutalongsidethe
Februarysurvey.
3.2Distributionandplacementofnestboxes
Allmajorbushpatchesontheislandcontainhihinestingboxes.Nonewboxeswereinstalledthisseason,thereare
190boxescurrentlyspreadacrosstheisland,whichismorethanenoughboxesavailableforthepopulation.
3.3Nestsitemonitoring
Completednestswerecheckedalmostdailyuntileggswerelaid.Wheneggswerefoundtobewarmorthefemale
observedsittingformorethan10minuteson2consecutivedaysincubationwasconfirmed.Thesenestswerenot
checkedagainuntilday13ofincubation,afterwhichtheywerecheckedeverydaytocheckforhatchinganduntilthe
chickswere10daysold.Afterday10thenestswerecheckedevery-otherdayuntilday21whenthechickswere
banded.Afterbandingthenestswerenotcheckedagainuntilday29andeverydaythereaftertodeterminefledging
dates.
3.4Nestboxmaintenance
Thirtythreenestboxeswerereplacedwithnewoneastheyhadbeenoutinthebushforsixyears.Allothernest
boxeswerecleanedatthebeginningoftheseason.Duringtheseasonallboxesthathadbeenusedforabreeding
attemptwerebroughtbacktobaseandscrubbedwithwater,sprayedwithtrigeneandlefttodryinthesunfor24
hoursbeforebeingreturned.Thebackboardswerescrubbedandsprayedwithtrigeneatthetimeofboxremovalso
theycoulddrybeforetheboxwasreturned.
3.5Supplementaryfeedingregime
Sugarwaterwasprovidedadlibituminchicken-feeder-styleplasticfeedersplacedinfeedingstationsat5-6locations
ontheisland.Feederswerecleanedinhotsoapywater,rinsed,andthensprayedwithtrigene,allowingaminimumof
5minutescontacttime.Thesewerethenrinsedandlefttodry.Feedingstationswerecleanedanddisinfectedwith
trigeneonMondays,WednesdaysandFridays.
3.6Bandingandmeasurements
Nestlingswerebanded,weighed,measuredandhadblooddrawnat21daysold,onafewoccasionsday22or23.
Tarsusmeasurementswere“tothenotch”and“fulllength”;“head-to-bill”wasmeasuredfrombackoftheheadto
thetipofthebeak.Eachnestlingwasgivenac-sizemetalband,agreypittagandacombinationof2plasticcolour
bands.Allplasticbandsweresealedusingthenewweldingmethod.Foralistofbandcombinationsand
measurementspleasecontactJohnEwen(john.ewen@ioz.ac.uk).
3.7Health
Mitecontrolwascarriedoutthisyear.Nestlingswithmitesweretreatedwithfrontlinetwice
Beforenestboxeswerereplacedwithnewboxes(asdetailedin3.4)andnestsreplacedwithafakenestmadefrom
wiremeshandpolarfleecefollowingtheSOP.Onlytwonestsrequiredtotalreplacementsuggestingthemite
infestationsthisseasonwerelow.Fourbirds(2male,2female)werefounddeadthisseasonandonemalefoundsick
whichlaterdiedincaptivity,necropsyreportsarefoundintheappendix.
4. Results
VisitornumberstoTiritiriMatangihavebeenestimatedusingthenumberofpassengerstravellingontheferry,this
was30,525for2015.
Figure1Numberofnests,eggs,chicksandfledglingsproducedonTiritiriMatangifrom1997to2015
Figure2HatchingsuccessonTiritiriMatangifrom1997to2015
Figure3NumberofbirdsrecordedeachyearonTiritiriMatangiduringthetwoannualsurveysfrom1997to2016.
Notethatthesurveyof09/10tookplaceimmediatelyafterjuvenilesweretranslocated;thesinglediamondshowsthe
surveyresultincludingthoseremoved.
Theresultsofthetrialsurveymethodusingdataloggersandantennaonthefeedercageswere:48individuals
recorded,10ofthesewerenotsightedbyobserversand1malehadnotbeenseenallseason.
5. Colourbandloss
Thelossofoneormorecolourbandsfromanindividualhihiresultsinanincompletecolourcombination,making
identificationduringpopulationsurveysandbreedingmonitoringambiguous.Thisproblemhasincreasedinrecent
yearstothepointthat26%ofbirdsrecordedintheSeptember2014surveyweremissingoneormorerings.During
the2014-15seasoneffortsweremadetoreducethisproblemandbandswerefixedwithsuperglue.
DuringtheSeptember2015survey19%ofbirdswerenotedasmissingoneormorebands,unfortunatelythisislikely
tomeanthatthesupergluefixingwasunsuccessfulasalongtermsolution.Itwasdecidedthisseasontotrialheat
sealingthejointoftheplasticband.Abatterypoweredsolderingironwasusedtomelttheplasticandformawelded
join.Alljuvenilesfromthisseasonand36%oftheadultpopulationhavehadtheircolourbandsweldedandsofar
therehavebeennojointfailuresorlossofbands.Thetypeofplasticthebandsaremadefromhasaneffectonthe
easeofmelting,theacetalbandsareeasiesttomeltandformthebestjoin.
6. Acknowledgments
TheDepartmentofConservationandtheSupportersofTiritiriMatangi(SoTM)arecriticalcomponentsofthisproject.
ManythankstoDaveJenkins,theever-supportiveTiriranger.SomanySoTMmemberswerehelpful,enthusiasticand
interestedasalwaysandweappreciatetheircommitmenttothehihiandthisislandproject.Hihiconservationalso
benefitshugelyfromtheHihisponsors,WesfarmersIndustrialandNZSafetyLtd.
7. Appendix(necropsyreports)