Vocal evidence of species rank for nominate Unicolored Tapaculo Scytalopus unicolor

6 Pages·2001·2.5 MB·

by  Paul Coopmans

Andrew Whittaker 208 Bull. B.O.C. 2001 121(3)
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TWreagyel.orD,.MC..A&..LJor.ng1.94A8..JN.e19w95b.irKdesyfarroemasPfeorrutahnrdeaEtceunaeddorb.irFdiseilnditahneaX,eZotoroolp.ic3s1.:B1i9r5d-l2i0f0e.International
(Birdlifeconservationseries5). Cambridge.UK.
Whittaker,A. 1998.Observationsonthebehaviour,vocalizationsanddistributionoftheGlossy-backed
BecardPachyramphus surinamus, a poorly-known canopy inhabitant ofAmazonian rainforests.
Arajuba6: 37-41.
Whittaker. A. & Oren. D.C. 1999. Important ornithological records from the Rio Jurua, western
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Address: ConjuntoAcariquara.Alexio.RuaSamaumas214.Manaus,Amazonas69085-053,Brazil; e-
mail: Birdingainternext.com.br
c British Ornithologists" Club 2001
Vocal evidence of species rank for nominate
Unicolored Tapaculo Scytalopus unicolor
by Paul Coopmans, Niels Krabbe
&
Thomas S. Schulenberg
Received12May2000
Salvin(1895) namedanewspecies. Scytalopus unicolor, basedonthree specimens
fromnorthern Peru, andthis species was recognizedby later authors (e.g.. Cory &
Hellmayr 1924). However, duringarevisionofthegenusScytalopus (whichformed
thebasis fortheclassificationofthe genusinPeters 1951 andMeyerde Schauensee
1966),Zimmer(1939)combinedunicolorwithfourothertaxa(latrans, subcinereus,
intermedins, mdpanirostris). Ofthis group, ^unicolor' was the oldest name, and
Zimmer'spolytypic speciestookthename Scytalopus unicolor.
The songs of suboscine birds, such as Scytalopus. are believed to be entirely
innate(Kroodsma 1982. 1984;seealsoIsleretal. 1998).Recentfieldstudies(Whitney
1994, Krabbe & Schulenberg 1997)have shownthatalmostallScytalopustaxathat
were treated as subspecies by Zimmer (1939) should be elevated to species rank,
primarily because of their diagnostically different vocalizations. Furthermore,
Arctander& Fjeldsa (1994) found apositive correlationbetweenvocal andgenetic
differences in Scytalopus. and showedthat allopatry andparapatry are no evidence
ofclose relationship.
As part of a re-evaluation ofthe species limits ofScytalopus based on voice.
.
Paul Coopmans et al. 209 Bull. B.O.C. 2001 121(3)
Krabbe&Schulenberg(1997)showedthatScytalopus"unicolor"parvirostrisdiffered
dramatically in voice from Scytalopus "unicolor" latrans and S. "w." subcinereus
(see below), making it clearthatparvirostris is a separate species. However, vocal
data were lacking for unicolor, and these authors left latrans, subcinereus, and
intermedinsassubspeciesofScytalopusunicolor,whichwasaconservativeapproach.
In 1998 PC obtained tape recordings oftwo individuals ofnominate unicolor
near Cajabamba (the type locality for unicolor), on the east slope ofthe Western
Andes in southern Depto. Cajamarca, northern Peru. These recent tape recordings
(as well as additional recordings ofa single bird obtained by Richard Webster and
RoseAnnRowlett, alsonearCajabamba, on20October 1996)revealthatbothsong
and calls ofnominate unicolor differ strikingly from those oflatrans, subcinereus,
andparvirostris (Figs. 1-2).
Distribution
Thetype series ofS. unicolorconsistedofapairfromCajabamba (2,750m), onthe
east slope of the Western Andes in southern Cajamarca, and of a female from
Huamachuco (3,175 m), c. 20 kmtothe south, also onthe east slope oftheWestern
Andes, inLaLibertad. Zimmer(1939) ascribedspecimensfromfurthersouthonthe
same slope in La Libertad (Succha, Soquian), at elevations ranging from 2,000 to
3,150m,tothis form, andalso includedfive specimens fromChugur, onthePacific
slope in southern Cajamarca. In addition, Koepcke (1961) identified a male and a
female from Sunchubamba, further south on the Pacific slope in Cajamarca, as
nominate unicolor. As Zimmer (1939) was well aware, its occurrence at Chugur is
problematic,asthislocalityisnorthofandnearTaulis,thetypelocalityofsubcinereus
m
Subcinereusrangesfrom 1,500to4,000 insouthwesternEcuador, andalsooccurs
onthe Pacific slope innorthernPeru southto southern Cajamarca (Nancho). Inthe
vicinityofHuambos, southernCajamarca,NKhastape-recordeditnearthecrestof
the Western Andes, and apparently it also descends the adjacent east slope ofthe
Western Andes, as two specimens from Cutervo seem to represent this form (see
discussion in Krabbe & Schulenberg 1997). The plumage differences between
subcinereusandunicoloraresoslightthatwehesitatetoacceptPacific sloperecords
ofunicolor, atleastuntil documentedbyvoice.
Intermedins occurs in the Utcubamba drainage in the northern Central Andes,
Depto.Amazonas,Peru(typelocalityLaLejia,2,743m).Nodefinitevocaldataexist,
but tape recordings from within its range (PC) suggest that it might be a distinct
species as well. For the moment we leave intermedins as a subspecies oflatrans,
whichitresemblesmorphologicallymorethanitdoesnominate unicolor.
LatransiswidelydistributedintheAndesofEcuador,Colombia,andVenezuela,
atelevationsrangingfrom 1,500to4,000m.AtthetypelocalityonCerroMunchique
in the Western Andes ofColombia, vocalizations are similar to those recorded in
inter-AndeanandwesternEcuadorandintheCentralAndesofColombia;birdsfrom
theAmazonian slope north ofthe Rio Marafion approachsubcinereus inthe male's
blackplumage,andintheirfairlysimilarvocalizations. Furtherstudiesareneededin
Paul Coopmans et al. 210 Bull. B.O.C. 2001 121(3)
orderto delimit theirrange in Colombia and to establish whetherVenezuelan birds
belongwiththem.
Identity ofthe modern tape-recordings from Cajabamba
Wewerenotableto obtain specimens ofthe tapaculostape-recordedatCajabamba.
InviewofthepotentialimportanceoftheserecordingstothetaxonomyofScytalopus
(seebelow),andthedifficultiesoffieldidentificationofScytalopusbasedonplumage
characters, we herejustify our identification ofthese birds as unicolor, with which
theyagreed intheiruniformgreycolour.
Species diversity of Scytalopus on the western cordillera of the Andes of
southwesternEcuadorandnorthwesternPeruislow.Throughoutmuchofthisregion,
from southernLoja southto Cajamarca, only a single taxon (subcinereus) is found.
LocallyinCajamarcatherearerecordsoiaffinis,whichisalsofoundfarthersouthin
Ancash (where it is the only Scytalopus recorded). We show below that the
vocalizations of the Cajabamba population differ dramatically from those of
subcinereus, making it very clear that these do not represent the same taxon. The
vocalizationsofaffinisarealsoquitedistinctfromthoseoftheCajabambapopulation
(seeFigs.30and31 inKrabbe& Schulenberg(1997)).
B.Whitney,commentingonanearlierdraftofthismanuscript, suggestedthat,in
the absence ofa specimen compared directly to the type ofunicolor, we could not
rule out the possibility that the tape recordings from Cajabamba represented not
unicolorbutinstead"anundescribedspecies ofScytalopus". Indeed, inthe absence
ofa specimen, we cannot rule out such a possibility (which, admittedly, even the
author ofthis suggestion regarded as low). In view ofthe low species diversity of
ScytalopusfromthewesterncordilleraofnorthernPeru,andinrecognitionthatunder
any circumstances the probabilities would be extraordinarily small that two
independent parties (Coopmans; and Webster and Rowlett) would happen upon a
previouslyunknownspeciesofScytalopusatthetypelocalityofunicolor,webelieve
that our equation of these tape recordings with unicolor is the only rational
hypothesis. One might propose the existence of a virtually unlimited number of
previously undetected taxa ofScytalopus, but our contention would be that such
suggestions may safely be put aside unless and until such time as the notion is
positively supported by tangible evidence, rather than speculation.
Vocalizations
Althoughoursamplesizeissmall(songsandcallsofthreeindividuals),thematerial
is consistent. The songofnominate unicolor(n= 3) (Fig. 1 D) is a simplephrase of
4-6notes,thefirstovertoneloudest,c. 2,400Hz,thefundamentalandhigherovertones
barely audible, each note becoming shorter and the pace increasing through the
phrase, which lasts 0.3-0.5 s andisrepeatedat 1 s intervals.
Both latrans (n = 55) and subcinereus (n = 49) have simple songs of single,
Paul Coopmans et al. 211 Bull. B.O.C. 2001 121(3)
endlessly repeated notes (Fig. 1 A-C), with at least three distinct harmonics, the
fundamentalandthefirstovertonebeingvariouslytheloudest;eastslopebirdsreferred
to latrans (n = 25) differby always having the fundamental loudest and by having
barelyaudibleovertones. Songsofeastslopebirdsandsubcinereusoftenbeginwith
rhythmicphrases.Theseareoccasionallyrepeatedanumberoftimes,butusuallythe
phrases become increasingly longer and the intervals shorter, soon becomeing a
repetitionofasinglenoteatconstantpace,whichvaries fromfourtoeightnotesper
s, fastest when the bird appears most excited. There is little or no geographical
A
2- A* *m Am
B
2- A V- ^
C
'" A r
l » *
c
% *-
1aiL- 2- «lk «* * % *< F(iAg)urS.eI1..lSaotnragnss,ofCSoctyotpaalxoi,puswtaEpcaucaudloors;.
(B) S. latrans, Napo, e Ecuador; (C) S.
E
% rVVVM latrans subcinereus, Loja, sw Ecuador;
2- \ \ (D)Nominate S. unicolor, near
Cajabamba (type locality), east slope
\VUvYW\ \W\ o(Ef)WSe.stacAuntdieross,trsisC,ajHaumaanrucca,o,nwc PPeerruu;;
2- (F) S. parvirostris, Pasco, c Peru. A-C
and E recorded by NK, D by PC, F by
TSS.
Figure 2. Calls ofScytalopus tapaculos.
(A) S. I. latrans, Cotopaxi, w Ecuador;
(B) S. latrans, Morona-Santiago/Azuay
5(rsi 4- A B c D E boundary, se Ecuador; (C) S. latrans
subcinereus, Azuay, sw Ecuador; (D) S.
*
£ 4& | latranssubcinereus,between Llama and
Huambos, Pacific slope near crest of
Frequency 0* the Andes, s Cajamarca, nw Peru; (E)
Nominate S. unicolor, near the type-
locality in s Cajamarca, nw Peru. A-D
Time(s) recorded by NK, E by PC.
Paul Coopmans et al. 212 Bull. B.O.C. 2001 121(3)
variation inthe songs and calls ofeach ofthese forms.
The songofunicolor(Fig. 1 D) is only slightlyhigher-pitchedthanthatofhigh-
pitchedindividuals oflatrans andsubcinereus (Fig. 1 A-C), andis distinctly lower-
pitchedthansongsofacutirostrisandparvirostris(Fig. 1 E-F). Thepaceandrhythm
remains fairly constant, evenathighexcitement such as afterplaybackofsong.
The contact call ofunicolor(n= 3) (Fig. 2 E) is a single note, rising and falling
symmetricallylikeaninvertedU,higher-pitched(loudestat2.5-3 kHz)thancallsof
latrans (n=40) (Fig. 2A-B) andsubcinereus (n- 18) (Fig. 2 C-D) (both loudestat
1.5-2.5 kHz), and lacks the slow rise in pitch to near the end of the note, so
characteristic ofcalls ofthose taxa.
Taxonomy
On the basis ofthe strong vocal differences between unicolor and the other three
taxa, we suggest that latrans, subcinereus, and intermedius be ranked as a species,
S. latrans (Blackish Tapaculo), distinct from a monotypic S. unicolor (Unicolored
Tapaculo). We acknowledge (as did Krabbe & Schulenberg 1997:58) that birds we
referto asS. latrans might comprisetwo ormore (allopatric orparapatric) species.
The vocalizations ofS. unicolor are so distinctive that they do not indicate which
taxon mightbe its closest relative. There is a striking resemblance inpattern to the
songofapopulation foundonthe east slope ofthe Andes incentralPeru(Fig. 1 E).
The nomenclature ofthe birds from central Peru is problematic; Fjeldsa & Krabbe
(1990) referred to these birds as an "unnamed species", although we follow the
arguments outlinedby Krabbe & Schulenberg (1997) forcallingthem acutirostris.
Nomenclatureaside,theresemblanceinsongbetweenunicolorandacutirostrismay
bepurelycoincidental. Webelievethatdeterminationofphylogenetic relationships
among taxa ofScytalopus will best be resolved through the application ofgenetic
studies.
Acknowledgments
WethankP. VanGasseandB. M.Whitneyforvaluable comments onthemanuscript.
References:
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(Empidonaxtraillii)areinnate.Auk 101:13-24.
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(Rhinocryptidae), with descriptions ofthe Ecuadorian taxa, including three new species. Pp. 47-
88 in J. V. Remsen (ed.) Studies in neotropicalornithologyhonoring TedParker. Ornithological
MonographsNo. 48,American Ornithologists' Union, Washington, D.C.
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Addresses: P. Coopmans, Snepkenshof 11, B-2460 Lichtaart, Belgium; e-mail
[email protected]; Niels Krabbe, Zoological Museum University of Copenhagen,
Universitetsparken 15, DK-2100, Copenhagen, Denmark; present address Sucursal 21 Casilla
791, Quito, Ecuador; e-mail [email protected]; Thomas S. Schulenberg, Department of
Zoology, Field Museum ofNatural History, 1400 S. Lake Shore Dr., Chicago, IL 60605, USA;
e-mail [email protected].
© British Ornithologists' Club 2001
A note on the correct type ofMacabra
Bonaparte, 1854 (Strigidae)
&
byJohn M. Penhallurick Steven M. S. Gregory
Received24June2000
Macabraasageneric(orsubgeneric)namehasbeenusedrecentlybyseveralauthors.
Wolters(1975-82: 71)listedMacabraasagenusincludingWhite-throatedScreech-
OwlOtusalbogularis,Bare-shankedScreech-OwlOtusclarkiiandRufescentScreech-
OwlOtusingens. Morerecently,Konigetal.(1999: 35)stated:"WetreattheAmerican
screechowlsOtusasmembersofsubgeneraMegascopsandMacabra,astheydiffer
from Old World scops owls in having two songs." They also listed Macabra
albogularis as a synonymofOtusalbogularis (1999: 279)
The history ofthe name Macabra is complex. It was first used by Bonaparte
(1854a: 112), where itis a nomen nudum. Bonaparte used it again inthe same year
(1854b: 541),onthatoccasionlistinganumberofspecies:"hylophilaTemm.;fasciata
Vieill.; suinda VieilL; melanota Vieill.; cayanensis Gm.; and albigularis Cassin."
Thesenamesincludespeciesfromseveraldifferentmoderngenera-Strixinthecase
ofRusty-barredOwlStrixhylophilaTemminck, 1825(1825:pi.373);Asiointhecase
ofStrixsuindaVieillot, 1817(1817: 34) (= Short-eared Owl subsp.Asioflammeus
suinda); Pulsatrix in the case of"melanota Vieill." (= Noctua melanota Tschudi,
1844 (1844: 266) = Band-bellied OwlPulsatrixmelanota); and Otus inthe case of