Table Of ContentBonnerzoologische Beiträge Band 55 (2006) Heft 2 Seiten 95-100 Bonn, Juli 2007
Bioacoustic Characteristics and Population Numbers of Endemie
Cinclodes oustaleti baeckstroemü (A\es: Furnariidae) Lönnberg, 1921
ofAlejandro Selkirk Island, Chile
Ingo Hahn '*
Pontifical Catholic University ofChile, Santiago, Chile
2) Present address: Institute ofLandscape Ecology, University ofMünster, Münster, Germany
Abstract. Twotypesofvocalisationoftheendemic MasafueraGrey-flankedCinclodes Cinclodesoustaletihaeckstroe-
niiiLönnberg, 1921 aredistinguished: contactcall andsong. Thecall isawhistle-like"chic"similartothatofthe main-
landtaxon C o. oustaleti. The song is described forthe firsttime and illustrated by sonagrams. It is a low, melodic se-
ries ofpearling notes uttered early in the morning. Song sequences vaiy in duration, being about two to five seconds
long. The frequency amplitude ofelements ranges from 5.3 to 7.7 kHz, showingcore frequencies from 5.8 to 6.8 kHz.
Elements are usually separatedby pauses ofabout0.03 seconds.At the beginningand end ofa sequence the song pau-
sesareextendedupto0.15 seconds. Thesongis lowandonly heardforashortdistance, maybeas it isaddressedtothe
partnerat one specific site. The first census counts ofthis endemic species were carried out usingthe line transect me-
thod. Both estimates ofits population size (in the years 1994/95 and2002) resulted in a total numberofapproximately
1500 individuals. Thus no negativepopulation trend wasdetected; however, this small population confirms the"vulne-
rable"conservationstatusoftheMasafueraCinclodes.Conservationmanagementshouldincludefurtherpopulationmo-
nitoringanderadicationofintroducedmammals.
Keywords.Vocalisations, song, call, MasafiieraGrey-flankedCinclodes,,(uan Fernandez, Cinclodes oustaletibaeck-
stroemii, transectmethod, islandcensus, conservation basis.
Resumen.DostiposdevocalizacióndelendémicoChurretechicodeMásafueraCinclodesoustaletibaeckstroemiiLönn-
berg, 1921 fueron distinguido, grito de contacto y canto. El grito es un gorjeo ("chic") similar aeso del C. o. oustaleti
en tierra firme. El canto ha sido descrito para primera vezy esta ilustrado porsonagrames. El canto es una serie de to-
nosbajosymelódicoscantadotempranoen la mañana. Secuenciasdecanto pueden variaren suduración,porlo menos
dedosacincosegundos. Lafrecuenciadeloselementostieneun rangode5,3 a7,7 kHzcon unafrecuenciaprincipal de
5,8a6.8 kHz. Elementosusualmente están separadosporpausasdepróximamente0,03 segundos. En el inicioy findel
canto pausas están alongadas hasta0,15 segundos. La rara y bajapresentación del canto da indicación para laausencia
de unaadaptación vocal compensativaa las condiciones isleñas ventosas. Usando el método de transectos lineares, dos
censosde lapoblación han sido realizados (en losaños 1994/95 y 2002), que han sido resultadosen un numero totalde
próximamente 1500 individuosen IslaAlejandroSelkirk. Poresonotendenciacriticade lapoblación ha sidodetectada,
peroelChurretechicode Másafueraesclasificadocomo vulnerable. Manejodeconservacióndebe incluirmonitoriode
supoblación e eiTadicación de mamíferos introducidos.
Zusammenfassung. Zwei Typen der Lautäußemng des endemischen Masafuera-Grauflanken-Ufei-wippers (Cinclodes
oustaletibaeckstroemiiLönnberg, 1921)werdenunterschieden: KontaktrufundGesang! DerRufisteinpfiffartiges„tschick"
ähnlich dem von C. o. oustaletiaufdem Festland. DerGesang wird hier erstmals beschrieben und durch Sonagramme
illustriert. Eristeine leiseundmelodisch vorgetragene SerieperlenderTöne,dieam frühen Morgen geäußert wird. Ge-
sangssequenzen können in derLängevon etwa zwei bis fünfSekunden variieren. Die Frequenzamplitude von Elemen-
ten reicht von 5,3 bis 7,7 kHz bei einem Kemfrequenzbereich von 5,8 bis 6,8 kHz. Elemente werden durch kurze Ge-
sangspausenvonca.0,03 Sekundenvoneinandergetrennt.AmAnfangundEndederGesangsstrophesinddiePausenbis
zu0,15 Sekundenverlängert. DerleiseundnuringeringerDistanzvemehmbareGesangistmöglichei'weiseandenPart-
neraneinembestimmtenOrtadressiert. MittelsderLinien-Transekt-MethodewurdendieerstenPopulationserfassungen
diesesEndemitendurchgeführt.DiedaraufbasierendenGesamtbestandszahlenführtenindenJahren 1994/95sowie2002
jeweilszueinerAnzahl von etwa 1500 Individuen aufAlejandro Selkirk. Demnach wurde zwarkein negativer Popula-
tionstrend festgestellt, aufgrund der kleinen Populationsgröße istjedoch der Gefdhrdungsstatus („vulnerable") flir den
Másafuera-Uferwipperzutreffend.SchutzmaßnahmensollteneinweiteresBestands-MonitoringunddieBekämpfungein-
geschleppter Säugetierebeinhalten.
96 Ingo Haiin: Bioacoustics ofCinclodesoustaletibaeckstroemiiofAlejandro Selkirk Island
1. INTRODUCTION The archipelago is biogeographically isolatedby lacking
any neighbouring islands within a 500 km-zone, and the
TheJuan Fernandez Islandsarethe mostimportantendem- cool HumboldtCurrentseparatingitfromtheSouthAmer-
ic birdareaofChile andhostmoreendemic birdtaxathan ican continent.Alejandro Selkirk (44.64km?) isofyoung
anyotherregionofthiscountiy(cf. Wege& Long 1995). volcanic origin, shaped like a big rock dome and is one
However, they face severe conservation problems as for ofthe steepestislandsworldwide. Itisentirelypartofthe
example seen by the low population size ofanother en- Juan Fernández national park founded in 1935, and UN-
demic landbird species, the Masafuera RayaditoAphrus- ESCO Biosphere Reserve since 1977. More detailed ge-
liini masafuerae(Philippi & Landbeck, 1866) (Philippi & ographical descriptions may be taken from Castilla
Landbeck 1866; Brooke 1987; Hahn 1998). Forthe en- (1987) and Skottsberg 1920-1956).
(
demicGrey-tlankcdCinclodes Cinclodesoustaletibaeck-
stroemii Lönnberg, 1921, a population census had never Field work was carried out on the island during the aus-
been carried out. Together with Aphrastura masafuerae tral summers from25 November 1992to 1 February 1993,
it represents a biogeographical outpost ofthe Neotropi- 15 December 1994 to 9 February 1995, and 23 January
cal ovenbird family (Aves: Furnariidae), being limited to to 8 Februaiy2002. Visual fieldidentificationofbirdswas
only Juan Fernandez in the South-east Pacific (cf. straight foreword, basing on Araya et al. (1992; cf also
Schlatter 1987). Jaramillo2003) andtheoriginal description(Lönnberg
1921 ). Acoustic identification waspossibleafterlearning
The collector Bäckström (Lönnberg 1921 ) and later ob- the birdvocalisationswhiletheywereundervisual obser-
servers (cf. Johnson 1967) reported Cinclodes oustaleti vation and taping with a DAT-Recorder (Sony, Type
baeckstroemii from Alejandro Selkirk as well as from HD-SlOO). An ordinaiy external microphone with addi-
Robinson Crusoe islands. Interpreting these sources, the tional wind protection was placed in suitable field posi-
population on Robinson Crusoe appears to have been tion. Evaluation ofthe tape recordings was done with the
smaller and more oscillating than that of Alejandro program AVISOFT-SONAGRAPH PRO.
Selkirk. However, probably due to lack ofadequate data,
recent reviews do not differbetween islands, and simply Forthe estimation ofbird populations a numberofmeth-
state the entire Juan FernandezArchipelago as the distri- ods have been developed during the past decades
butionarea,therefore includingalso SantaClara(Jaramil- (overviews in Ralph & Scott 1981; Bibby et al. 2000).
LO2003; Remsen 2003). Dueto its insulardistributionarea The abundance data should reach a high level ofcompa-
and the general conservation problems ofthe archipela- rabilityandcoveramaximumarea.Thereforethelinetran-
go, thisendemic cinclodeswasalreadyclassifiedas"vul- sect method was chosen (description by Emlen 1971,
nerable" in the red list ofterrestrial vertebrates ofChile 1977). Although a quantitative method is determined to
by Glade (1993). be efficient iftwo-thirds ofthe present birds are record-
ed (Eberhardt 1978), I aimed to record a significantly
Little is known about its population and biology in gen- higher portion. Thus, I chose a small transect width, and
eral, partly in relation tothe remotenessofthe islandsand triedto recordbirdsbyvisual aswell asvocal contact. On
thebadly accessibleteirain.An additional difficulty ham- the Juan Fernandez Islands a total of 111 line transect
pering any population census was the fact that its vocal- countswerecarriedout from 1992 to2002. Differenttran-
isations had not been described. However, reliable cen- sect areas and habitat types were covered (fordetails see
sus data are fundamental for any conservation manage- Hahn 1998).
ment. Presentingthe firstdescription ofvocalisationsand
the first population data, 1 aim to provide basic informa-
tion fortheendemic MasafueraCinclodes. It mayhelpre- 3. RESULTS
searchers and managers to acoustically identify individ-
uals in the field, and to monitorthe population in the fu- Cinclodesoustaletibaeckstroemiiisasmall brownish-gi"ey
ture. birdofgenerally inconspicuousappearance, showinglong
white-framedtail feathers,awhitish superciliarstripe, and
a small body size (cf also Fjeldsä & Krabbe 1990;
2. METHODS RiDGELY & Tudor 1994; Remsen 2003). It flicks its tail
up and down like a wagtail, often in the vicinity ofwater
The study area is IslaAlejandro Selkirk (formerly Mása- in abrook. Itsearchesrocks,boulders, stonewalls,moss-
fuera),thewesternmostislandoftheJuanFernándezArch- es, and lichens forarthropod prey, flyingmostlyforshort
ipelago (33°45'S and 80°45"W). Alejandro Selkirk is in duration anddistanceonly. Even in flightthebirdreminds
the South-east Pacific 167 km west ofthe othermajoris- to wagtails (Motacilla), for example when dynamically
land RobinsonCrusoe, and 769km offthecoastofChile. manoeuvring with its long tail to follow a flying insect.
Bonnerzoologische Beiträge 55 (2006) 97
Itmostlylandsontopofstones,rocksorotheropenplaces. Songelementsare limitedtofrequenciesbetween 5.3 and
Only rarely it may land on ferns or other tall plants. No 7.7 kHz (Fig. la). Within this amplitude the extension of
individuals were observed inside the vegetation. elements varies and a wave-like structure is recognised.
In Figure lb it is visible that the frequency ofsong ele-
Description ofvocalisation types ments isslightlydifferent. Singleelementsaremostlyopen
Two principal types ofvocalisation were identified: call below or sometimes have the structure ofan "S" laid on
andsong. Thecall is amonotonous "chic"ormayalsobe its side (e.g., last elementofFig. lb). The short sequence
titled a whistle-like call. It is uttered very similar (Fig. 2) illustratesthemostcoveredfrequency level of5.8
throughoutthewholegenus, eithersingleorin a loosese- to 6.8 kHz. This corresponds to frequency amplitudes of
ries ofcalls. The song ofthis endemic taxon was record- single elements covering about one kilo hertz (kHz). At
ed for the first time and is described here through son- thebeginningandendofthesequencesingleelementsarc
agrams (Figs. 1 & 2). Itisutteredin the early morning by aiTanged looser/slower(0.1-0.15 sec),whereas in thecen-
only one individual ofthe pair (probably the male). The tral song elements are closer to each other, and thus fol-
song is a melodic series ofpearling notes. lowingfasterwithpausesofapproximately0.03 seconds.
1 sec.
Fig. 1 (a & b). SongoftheMásafueraGrey-flankedCinclodes CinclodesoustaletibaeckstroemiiLönnberg, 1921 onAlejandro
Selkirk Island. A) Long sequence of5.5 seconds (N=256, F=100, 0=0, kHz =22); B) Section ofAof 1 seconds duration (from
4.75to5.75 sec.onthetimescale)(N=512,F=50,0=93.5,kHz=22.05);EvaluationlevelsoftheprogramAVISOFT-SONAGRAPH
PRO are given inparentheses.
98 Ingo Hahn: Bioacoustics ofCinclodesoiistaletibaeckstroemiiofAlejandro Selkirk Island
Fig. 2. Song ofthe Másafuera Grey-flanked Cinclodes Cinclodes oustaleti baeckstroemii Lönnberg, 1921 on Alejandro Selkirk
Island. Short sequence of 1.8 seconds duration (N=512, F=50, 0=88, kHz =22).
Cinclodes oustaletibaeckstroemii
1600
1400
200
0) 1
E 1000
C
C 800
600
o
0)
Q. 400
Vt
200
0
Census 1992-95 Census 2001/02
Fig. 3. Total population numbersoftheMásafueraGrey-flankedCinclodesCinclodesoustaletibaeckstroemiiLönnberg, 1921 on
AlejandroSelkirk Islandincomparisonoftwocensusperiods. Censuseswerecarriedoutusingamodifiedversionofthelinetrans-
ect method (cf Hahn 1998).
Population numbers ous non-transect excursions. Thus the Másafuera Cin-
During census counts and additional observations from clodes is presently interpretedto be endemic onlytoAle-
1992 to 2002 no Másafuera Cinclodes specimen was ob- jandro Selkirk, in spite ofthe fact that single individuals
served on the islands Robinson Crusoe and Santa Clara. also have been seen on Robinson Crusoe in the past
This is an important result, as C. o. haeckstroeniiiwasre- (Lönnberg 1921). They inhabit all elevation levels up to
peatedlyobservedon RobinsonCaisoeduringthe lastcen- thetopofthesummitofLos Inocentes (1320m)andmay
tury (Lönnberg 1921; Johnson 1967), and even recent be found in all habitat types. Preferred landscape struc-
reviews state the whole Juan Fernandez Archipelago as tures are the washes and V-shaped Quebradas, which al-
thedistribution area (Jaramillo2003; Remsien 2003). On socarrywaterinthesummer; forexample, theQuebradas
Alejandro Selkirk they were recorded during eight tran- Tongo, Varadero, Inocentes, Vacas, Casas, Sanchez, and
sectcountswith49 specimens,andmappedduringninncr- Guatón.Therockybeachesareonlyoccupiedwherefi^esh-
Bonnerzoologische Beiträge 55 (2006) 99
water is nearby, for example at the end ofQuebrada In- Thetotal population sizeofabout 1500correspondstoan
ocentes. However, MásaftieraCinclodesmay beabundant average density of 3.4 individuals per 10 hectares. This
in some upland regions too, where no permanent waters seems to represent a realistic value, taking into account
exist, namely in moist areas often covered with clouds. that the well-watered canyon bottoms are the preferred
Few specimens were seen resting on thetop oftall plants habitat, and that pastures or otherdry areas remain unin-
or visiting dry grasslands where no washes are nearby. habited. Throughthe impactoffiresandintroducedgoats
the open habitats increased on the island since discovei^
Only a very few indicators exist to reconstruct the popu- in 1574. Through such destruction ofvegetation, several
lationdevelopmentofCinclodesoustaletibaeckstroeinii. ofthe canyons in the North ofthe island carry no water
Intheyear 1917, Bäckström(Lönnberg 1921)calledthem duringsummer,butprobablyhavedonesowhen theveg-
"common" incertain regions ofAlejandro Selkirk. In the etation was intact. Thus, many northern canyons present-
year 1986. Brooke (1987) made a similar general state- ly are not inhabited by C. o. baeckstroeinii due to lack of
ment. In 1994/95 I carriedoutthe firstcensus ofthis cin- freshwater.
clodes, whichresulted in an estimate ofabout 1500 indi-
viduals. Onthis setofdatanopopulationtrendoranytype Anotherthreatcomes fromintroducedpredators. CatsFe-
offluctuation can bereconstructed forhistorical times. It lis catus f catus (Linnaeus, 1758), Norway rats Rattus
seemsthatthisendemic taxonwaswidelydistributedand norvegicus (Berkenhout, 1769), Ship rats R. rattus (Lin-
quite common on Alejandro Selkirk during the last cen- naeus, 1758), and House mice Mus inusculus (Linnaeus,
tury. The 2002 census also led to a size ofapproximate- 1758) have landed onAlejandro Selkirk, and have grown
ly 1500specimens.Thusnochangesinthepopulationsize wild(Hahn & Römer2002).At leastcatsandmaturerats
have taken place within this seven year period. Also no are able to prey on adult passerine birds (Römer 1995),
significant differences were found by comparing exactly butall fourareknown topreyon birdbroods. The impacts
the same three transect routes on Alejandro Selkirk in ofthese pest species on the population ofthe Másafuera
1994/95 (20 individuals) and in 2002 (19 individuals). Cinclodes havenotyetbeen investigated. Taking into ac-
count its small distribution range, especially the absence
from Robinson Crusoe,thisendemic speciesshouldbeup-
4. DISCUSSION graded intheChilean Red Listfrom"vulnerable"(Glade
1993)to"endangered".Thepopulation sizeshowsnocrit-
Thecommoncall ofC. o. baeckstroeiniisoundsverysim- ical trend, but should be monitored for a five-year inter-
ilar to that of C. o. oustaleti, and even to some other val. The principal conservation goal must be the eradica-
speciesofCinclodesonthe mainland. Itsprimerfunction tionofall introducedmammals, butforefficiency reasons
seemstokeepvocal contactbetweentwopartnersormem- campaigns should start with goats.
baefrisneofaandfarmaitlhyerpalrotyw.vTohcealsisoantgioonftCy.poe.thhaaetckisstnrootenhieiiarids Asicoknnso(wVl.eRdeggeimone:nt0s3./9I4a&m0g1ra1t/e0f1u)l, atondthteoCthOeNRoAjFasfaorndpeLrónipiesz-
beyond a distance ofmore than 100 m. Thus, no obvious families on Juan Fernández for hospitality, and to M. Fernán-
audible adaptation to the harsh and windy conditions on dez in Santiago (UC) for discussion. H. Mattes (Münster), K.
thisoceanic islandcan be identified. In contrast,twooth- Conrads,W. Beisenherz,andU. Römer(all Bielefeld)comment-
er endemic landbirds [Aphrastiira masafuerae and edon terminology and literature. Thanks to DAAD (1994) and
AvH (2001-03) for funding.
Sephanoidesfernandensis) have developed significantly
louderand/ormore intensevocalisationson theJuan Fer-
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