A Cryptic New Species of Flycatcher (Tyrannidae Suiriri)

8/3/2019 A Cryptic New Species of Flycatcher (Tyrannidae Suiriri)

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COLOR L^FE. ChapadaFlycatcher, new species f tyrant-flycatcherTyrannidae:Suiriri) from the cer-rado regionof centralSouthAmerica.The male is pictured in profile on the left; the female s displayingwith wings raised,on the right. From a watercolorpaintingby Daniel E Lane.


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The Auk 118(1):56-78, 2001

A CRYPTIC NEW SPECIES OF FLYCATCHER (TYRANNIDAE: SUIRIRI)FROM THE CERRADO REGION OF CENTRAL SOUTH AMERICAKEVIN J. ZIMMER, '2'5 NDREWWHITTAKER, AND DAVID C. OREN

tLosAngeles ountyMuseumof NaturalHistory,900 Exposition oulevard,osAngeles, alifornia 0007, USA;21665GarciaRoad,Atascadero, alifornia93422, USA;3EstradooAleixo,Conjunto cariquara ul, Ruada Samaumas14, Manaus,Amazonas, razil69085;and4DepartamentoeZoologia,MuseuParaense m'lioGoeldi,Caixa Postal 399, 66.017-970 Beldm,Pard, Brazil

ABSTRACT.--Aew species f tyrant flycatcherSuiriri slerorum)s describedrom the cer-radoregionof Braziland adjacent asternBolivia.Thespecies reviously adbeenconfusedwith Suiriri suiriri affinis,with which t is syntopicat multiple sites.The new specieswasfirst dentifiedby voice.Althoughcryptically imilar o S.s.affinisn many espects,henewspeciess readily dentifiedby all vocalizations,ill size,colorpatternof the ail, and shapeof the central ectrices.Mostdistinctive re the male-femaleduets,whichare accompaniedby dramaticwing-lifting displaysnot performedby any congeners. eciprocal laybackex-perimentsof tape-recorded ocalizations emonstratedhat the new species nd S.s.affinisdo not respondo oneanother's ocalizations. eprovide nformation n thenaturalhistoryof the new flycatcher, long with spectrograms f its variousvocalizations.We alsoprovidevocalanalysisof all othernamed axa n Suiriri,and discusshe various ntragenericela-tionships. n particular,S.s. affinis nd S.s. bahiae, lthoughdistinctmorphologically,revocallyand behaviorally imilar,and respond o oneanother's ocalizationsn playback x-periments.Received7 December999, accepted September000.THE GENUS SUIRIRI has been the focus of tax-

onomicdebate or decades.Two species radi-tionallywererecognized, short-billed, hite-bellied nominate form Suiriri suiriri; and alonger-billed, yellow-bellied form, S. affinis.The apparent ntermediacyof a large seriesofSuiriri rom northeastern araguayed Zimmer(1955) o suggest hat the two taxa were con-specific.Meyer de Schauensee1966)and Tray-lor (1979) ollowedZimmer in recognizingonlyonespecies f Suiriri,whereasShort 1975)didnot agree hat Paraguayan irds showed ignsof intergradation and continued to recognizetwo species.raylor 1982) eexaminedhePar-aguayanmaterial n the AmericanMuseumofNatural History (AMNH), and found it as de-scribedby Zimmer, concurring hat S. suiririand S. affinisshouldbe treatedas conspecific.More recent authors have remained divided:Sibley and Monroe (1990) recognized wo spe-cies of Suiriri, whereas Ridgely and Tudor(1994) recognizedonly one.As currently reat-ed, the genusalso ncludesoneadditional ax-on, S.s. bahiae, yellow-bellied taxon fromnortheasternBrazil. Hellmayr (1927) treated

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bahiae s a subspecies f S. affinis, rom whichhe found t to differ from typical formsby "up-pertail covertsdark hair brown like the tail;rectriceswithout any yellowishat the baseandwithout the pale brownishapicalband."Zimmer (1955) pointed out an additionalcomplication:ive AMNH specimens f S.affin-is from Mato Grosso and Goias, Brazil, all ofwhich were anomalous n having a short,broad-basedbill and with the "pale terminalband on the rectricesunusuallywide and dis-tinct, exceeding ny other specimen t handwhether from the same or other localities andwhether suiriri, affinis,or bahiae." immer fur-ther noted that "the significance f this com-binationof characterss completely uzzling,since here is no allied group toward whichthese features,singly or together,suggestatrend." In his reexamination f Suiriri, Traylor(1982)commented n the five aberrentAMNHspecimensand an identical specimen fromMaranhao, Brazil (from the Field Museum ofNatural History,Chicago; ereafterFMNH). Inaddition o the shortbill and broad,pale tips tothe rectrices,he six specimensurther couldbedistinguishedrom typical affinisby their dis-tinctly broader central rectricesand a lack of

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58 ZIMMER,WHITTAKER,NDOREN [Auk, Vol. 118any contrastingpale edging to those feathers(Traylor 1982). Traylor noted that "ordinarilythe close correlation of two such discrete andunrelated characters as the short bill and thecoloration nd shapeof the rectriceswould bestrongevidence hat we have two siblingspe-cies. think that eventually his will prove tobe true,but the possibility hat the short-billedbirds may somehow e related o the intergra-dation betweenaffinisand suiriri cannotbe ig-nored at this time." He concluded y stating"most important,without field studiesof thevarious taxa, it is useless o speculate."During the courseof severalyears of fieldwork at various sites in Brazil Zimmer andWhittaker found that there were two markedlydifferent vocal types of yellow-bellied Suiriri,oneof whichwasrelativelywidespread, ccur-ring from Amapa to Bahia to Goias;and theother which we knew only from the ChapadadosGuimaraes egionof Mato Grosso. he firsttype includedbirds that, by both distributionand morphologicalharacters,learlywere as-signable o S.s. bahiae,s well asbirds that ap-peared to be typical of S.s. affinis.The secondtype was distinctive not only for its vocaliza-tions, but also for its dramatic wing-flappingdisplays hat invariablyaccompanied ll terri-torial duetsby mated pairs (seebelow). Recip-rocal playback experimentsconductedat mul-tiple sites evealed hat the two vocal ypesdidnot respond o one anothers'vocalizations.nSeptember 998,we found the two vocal ypesoccurring syntopically near Cuiaba, MatoGrosso,Brazil.Closecomparisonevealed hatonevocal ype wasnoticeably hort-billed om-paredto the otherandhad a distinctbuffy ter-minal fringe to the tail, and that the birdswerealwaysassortatively aired with their own vo-cal and morphologicalypes.Suspectinghat the short-billed irds repre-sented he samebirds as the anomalous peci-mens reported by Zimmer and Traylor, we re-turned to the Cuiaba egion n September 999with Dionisio Pimentel of the Museu ParaenseEmilio Goeldi, Belem (hereafter MPEG) andcollected 0 specimens f eachvocal ype.Priorto collecting, e madevoucherape-recordingsof eachbird (all recordingso be archived t theLibrary of Natural Sounds,Cornell Laboratoryof Ornithology, Ithaca, New York; hereafterLNS). Tissue samplesalso were preserved ormolecular analysis of genetic differences.All

specimens nd tissue sampleswere depositedwith the MPEG. We also located additionalsitesof sympatrybetween he two vocal ypes.

METHODSWe made observations of Suiriri at various sites in

Mato Grosso,Brazil (August and October1991,andevery September rom 1993 to 1999); Pernambuco,Brazil (each anuaryrom 1996 o 1999,and February1996);Goias,Brazil (January 996);and Amapa,Bra-zil (February1998and 1999).All measurements sedin behavioraldata (e.g. distances, eights)are esti-mates. Sexual identification of birds in the field wasbasedon sex-specific,tereotyped isplays r vocal-izations, he sexual specificityof which was con-firmed by postmortemnspection f specimenshatwe collected.Mapped distributionsas hey appearin this paper) are basedentirelyon labeldata romspecimenshat the seniorauthorexamined,on morerecentrecordsdocumentedby tape recordings, ndon our own collecting ites.Those ocalitieswereen-tered into a sector-based eographic nformationSystem Isler 1997)and mappedby Morton sler.We assume that vocalizations of Suiriri, like thoseof other suboscines,re mostlyor entirely nherited(Kroodsma1984,1989;Kroodsmaand Konishi1991),and as such,provide potentially nformativechar-acters for systematicstudy as in other suboscines(Lanyon1978, sler et al. 1997,Krabbeand Schulen-berg 1997).To analyzevocalizations,we assembledrecordings f all named axa of Suiriri or compari-sonwith our own recordings. ocations ndrecord-ists or all recordings xaminedare istedbelow.Forcomparison, ocalizations ere categorized s oud-songs, uets,or calls."Loudsongs"wereconsistent-ly patternedmultinotevocalizationsIsleret al. 1997)givenby an ndividualbird, seeminglyn thecontextof territorialadvertisement. hosewere given ndi-vidually by both sexes, ut most frequentlywere n-corporated nto duets. "Duets" involved simulta-neoussingingby a pair of Suiriri, and consisted ftypical oudsongs f both sexes, ombinedwith oth-er calls.Vocalizations ategorized s callsmostoftenwere structurally simple (typically involving onlyoneor a few notes; xceptions re notedbelow)andusually were given n the contextof contact ocali-zationsbetween mates or family members.Our re-cordingswere made with SonyTCM-5000 ape re-corders and Sennheiser ME-80, ME-66, and MKH-70shotgunmicrophones. pectrograms ere madebyPhyllis sler on a MacintoshG4 computer singCa-nary version1.2.1 (Bioacousticsesearch rogram,Cornell Laboratory of Ornithology, Ithaca, NewYork).Canary parameterswere standarddefaultex-cept hat frame overlapusedwas >-96.88%.Playback experimentswere conducted o deter-minereactions f Suiririof each ype to vocalizations


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January 001] NewFlycatcherromCerradoegion 59of the others. n eachcase,an individual or pair offlycatchersirst was presentedwith a prerecordedtapeof another axon.Eachprerecordedape nclud-ed a combined10 to 15 songsand duets interspersedwith calls) rom two pairs of birds of a given taxonand geographicocality.For he S.s. suiriri ape,weusedonly songs ndcallsbecause e had no record-ings of duets. For all trials, each taxon was repre-sentedby a singleplayback ape consisting f vocal-izations of two pairs (or individuals in the caseofnominateSuiriri)of birds.During each rial, the apeof 10 to 15 songsand duetswasplayed o conclusion.To avoid confounding effects, a buffer period ofabout2 min was used o separateplaybackof vocal-izationsof different axa.Flycatchershat did not re-spond o playback f other axa henwerepresentedwith a playback ape of their own vocal type. Thatwasdone o account or potentialseasonalnfluencesby resolvinghe question f whetherbirds hat wereunresponsiven the first trials were discriminatingbetween he differentvocalizations, r were gener-ally nonterritorial uring he trial periodand here-fore unresponsiveo playbackof any kind. Failure oaccount for seasonal differences in responsivenesshasbeencitedas a potentialdesignweaknessn oth-er playbackexperiments Kroodsma1986).Respons-es to playback were characterizedas "strong,""moderate, ... weak," or "none." A strong responseinvolved immediate and repeated vocalizations(from previouslynonvocalizing irds) as well as ap-proach toward the sound source.A moderatere-sponsenvolvedeither a cautious pproachwithoutvocalizing, or sustained vocalizing without ap-proach.A weak responsenvolvedsingleor unsus-tainedvocalizationsfrom previouslynonvocalizingbirds)without approach. he nonecategoryncludesinstancesn whichbirds remainedsilent (in the caseof previouslynonvocalizingbirds) and did not ap-proach the sound source,as well as instances nwhich alreadyvocalizingbirds neitherchangedhedelivery or rate of their vocalizations,nor ap-proachedhesoundsource. potential ifth categorywouldbe a "negative esponse,"n which he subjectbird responded o the soundstimulusby moving ar-ther away.No negative esponseso playbackwereobserved rom any taxa.Zimmer examined representative specimensofSuiriri (n = 170) for comparisonwith our 20 speci-mens from Mato Grosso. Those specimensarehoused at the Museu Paraense Emilio Goeldi, Belem,Brazil MPEG);Academy f NaturalSciencesf Phil-adelphia,Philadelphia ANSP); CarnegieMuseum,Pittsburgh CM); Field Museumof Natural History,Chicago FMNH); Los AngelesCountyMuseumofNatural History,LosAngeles LACM); the LouisianaState University Museum of Natural Science,BatonRouge LSUMZ); he Museumof Vertebrate oology,Berkeley MVZ); the National Museum of NaturalHistory,Washington, .C. (USNM); and the Peabody

Museum of Natural History, Yale University (YPM).A wing rule with a perpendicular top at zero wasused to measure lattenedwing chord (wing), taillength tail), breadthof the pale terminal ip to therectrices pale tip), and width of the centralrectrix(centralrectrix), and dial caliperswere used o mea-sure tarsus ength (tarsus),culmen ength rom theanterior end of the nares to the tip (culmen), billdepth at the anterior end of the nares (bill depth),and bill width at the anterior end of the nares (billwidth). All calipermeasurements ere made o thenearest0.01mm, those taken with the wing rulewere made to the nearest 0.5 mm. General linearmodels were used to investigategender-correcteddifferencesamong taxa for each of the charactersmeasured.Residual diagnosticsndicated no viola-tionsof the general inear modelassumptionsf er-ror normality and constantvariance.Plumage wasdescribed rom specimens nd compared o a stan-dard color reference Smithe 1975).

RESULTS

Examinationof our specimens nd tape re-cordings,study of a large selectionof museumspecimens, xtensive ield observationshat n-cluded reciprocal playback experiments,anddiscovery f multiple sitesof sympatrywithoutevidence f interbreeding onvinced s that hetwo vocal types of yellow-belliedSuiriri rep-resentdistinctbiologicalspecies. urthermore,it is clear that the short-billed form that we col-lected from Mato Grosso is the same unnamedform that was first pointed out by Zimmer(1955)and later hypothesizedo be a crypticspecies y Traylor (1982).We propose o namethis flycatcher

Suiriri islerorum sp. nov.ChapadaFlycatcherHolotype.--MPEG No. 54867, adult femalefrom kilometer 2 on the road to Agua Fria,1525'S, 546'W,west of the town of Chapadados Guimaraes, approximately 720 m eleva-tion, state of Mato Grosso, Brazil, collected 21September 999by DionisioPimentel, ape-re-cordedby Kevin J. Zimmer. Voice specimen obe archived at Library of Natural Sounds(LNS), CornellLaboratory f Ornithology,th-aca, New York.Diagnosis.--Similar n plumage and size toSuiriri s. affinis Tables1 and 2), but differs asfollows:bill distinctlyshorter, elativelybroad-er, and more nearly uniform blackish (baseof


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60 ZIMMER,WHITTAKER,NDOREN [Auk, Vol. 118TABLE . Measurements mm) of Suiriri islerorum nd congeners.Valuesare means _+standarddeviationfollowedby ranges,with samplesize n parentheses.

Characters S. slerorurn S. affinis S. bahiae S. suiririCulmen 8.0 _+ 0.7 9.6 -+ 0.6 8.5 0.7 7.7 _+ 0.47.5-8.6 (23) 8.2-11.1 (61) 7.9-9.2 (3) 6.7-8.7 (108)Bill depth 4.2 _+0.3 4.6 _+0.3 4.5 _+0.9 4.2 _+0.33.7-4.9 (23) 3.8-5.4 (61) 4.5-4.6 (2) 3.7-4.9 (106)Bill width 5.7 0.3 5.4 _+ 0.4 5.5 0.1 5.0 0.3

5.1-6.3 (23) 4.7-6.1 (61) 5.4-5.6 (2) 4.4-5.6 (107)Wing 82.6 _+3.3 82.0 _+4.4 77.2 4.0 73.0 3.372-87 (21) 70-88.5 (38) 73.5-81.5 (3) 65.5-81 (108)Tail 71.5 2.7 69.4 + 3.8 66.7 4.2 69.0 3.666-78 (21) 59-76 (38) 62-70 (3) 58-78.5 (108)Tarsus 20.3 + 0.7 20.5 + 1.0 20.3 0.7 19.8 _+ 0.719.1-21.7 (20) 17.2-22.5 (37) 19.8-21.1 (3) 17.9-22.1 (106)Pale tip 6.4 + 1.5 2.1 1.5 1.2 2.0 0.0 - 0.03-11 (23) 0.0-4.8 (61) 0.0-3.5 (3) 0.0 (108)Central rectrix 10.5 _+ 1.1 8.6 1.3 7.0 + 1.0 --8-12 (21) 6-11 (38) 6-8 (3) --

mandible leshy-pink n many specimens f af-finis, particularly in females);dorsal surfaceofmost of tail darker, more blackish-brown(browner, between Fuscous,color #21, and Van-dyke Brown, color#121, in affinis);pale termi-nal fringe to tail broaderand morehighly con-trasting (either absent,or, if present,narrowand weaklycontrastingn affinis); oth websofouter rectricesmore extensively ale, and darksubterminal atchon inner web of outerrectri-cesdistinctly smaller;centralrectricesbroaderand without paler edges;white of throat ex-tends artherup on sidesof face to the gape n

S. slerorurn;nly to the bottomof thebill in allS.s. affinisexamined).Suiriri islerorurn iffersfurther from specimens f S.s. bahiaen havingthe grayish crown and nape less sharply de-marcated rom the greenerback; back darkerand less distinctly green;breast ess whitish;rump and uppertail covertsmore contrastinglypale; and central rectricesbroader and notpale-edged. Suiriri islerorurn iffers from S.s.suiriri as follows:distinctly arger overallwithproportionately shorter, broader tail; belly,flanks, highs,and crissumyellow rather hanwhite; undertailwith a broad,contrasting ale

TABLE . Means SD (samplesizes n parentheses) f measurementsmm) of Suiriri islerorum nd S.s.affinis y sex, ollowed y a statistical omparisonf themeans f thepooled amplesbothsexes)or eachspecies. aluesof P (= probabilityof a greatervalue of F) derived from Analysisof Variance ANOVA).islerorum affinis

Characters Males Females Males Females PCulmen 8.1 0.4 8.0 0.3 9.8 -+ 0.5 9.3 0.5


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January 001] NewFlycatcherromCerradoegion 61

FIc. 1. Displaying pair of Suiriri islerorum:emalein foregroundwith wings aised.Keymorphologicalfeatureshat distinguish hisspeciesrom S.s.affiniscan be seen n this photo: he short, thick bill, andthe broad, pale, terminal fringe to the tail. Photo-graphed earCuiab,MatoGrosso, razilon22Sep-tember 1999 by Kevin J. Zimmer.

base (undersideof tail in S.s. suiriri entirelydark except or contrastingly ale narrow outerweb of outerrectrix on eachsideand pale shaftof outer rectrices);central rectricesdistinctlybroaderand not narrowlypale-edged n eitherweb; inner web of outer rectrix pale-basedandpale-tipped,not entirelyblackish; roadergrayband across he breast; ess extensivelydarkauriculars; nd lessdistinctwhite supraorbitalbrow. Suiriri islerorum differs from both Suble-gatusmodestus nd Sublegatusrenarumas fol-lows: markedly larger; greener upperpartsshowingmore contrastbetweennape and back(brownerwith little or no contrast n Sublega-tus);rump and uppertail covertscontrastinglypaler than back (no contrast n Sublegatus);p-persideof tail blacker lessbrown) with a palebase o therectrices;hroatcontrastingly hite.The new species iffers from mostmembersofElaenian lacking elongatecrown feathersanda contrastingly colored, concealed coronalpatch, s well as n havingan entirelyblackishbill. The contrastingly ale rump and baseofthe tail are characters not found in Elaenia.

Descriptionfholotype.--Seeigure 1 and col-or plate. Capitalized colornamesand numbersare from Smithe (1975). Forecrownbrownishgray,closest o Hair Brown (color#119A), suf-

fusing nto a grayerhindcrown ndnape,clos-est to Glaucouscolor#79). The grayishnapegrades nto an Olive (color#30) back and scap-ulars. Uppertail coverts nd rump contrasting-ly paler than back,betweenLight Drab (color#119C) and SmokeGray (color#45). Auricularsconcolorwith hindcrown, perhaps slightlyduskier Malar region between whitish andPale Neutral Gray (color #86). Lores slaty. Anarrow,pale, supraorbitalbrow extends o theforehead. our ongrictal bristleson both sidesof gape, he longest8.0 mm. Wingsgenerallydusky, closest o VandykeBrown (color #221),but secondaries arrowly pale-edged (closestto Light Drab, color#119C)on outerweb.Basalportion of inner web of all remiges broadlypale-edged,betweenPaleHorn (color#92) andDrab-Gray (color #119D). Greater and mediansecondary overtsbroadly tipped Light Drab(#119C), orming two distinctwingbars.Axil-lariesand underwing iningspale SulphurYel-low (color #57).Chin and throatwhitish,gradingposterior-ally into Pale Neutral Gray (color#86). Centerand sidesof breastGlaucous color #80), sepa-ratingwhiter throat rom SulphurYellow color#57)belly, lanks, highs,andundertailcoverts.Most of exposeddorsal surfaceof tail dark, be-tween Dusky Brown (color #19) and DarkGrayishBrown (color#20). Contrasting alerband at tips of rectricesbetween Drab (color#27) and Dark Drab (color#119B); hat paler tip7 mm in lengthon central ectrix.Baseof bothwebs of outer rectrices, and base of inner webof all otherrectrices ontrastingly ale,closestto Cream color (#54). That paler base to tailmostly concealed rom aboveby uppertail co-verts, but visible from below as a wide (35 mm)pale base that contrastswith a dark centralpanel (closest o Vandyke Brown, color #221),which n turn, contrastswith the pale terminalfringe.Basalportionof the shaftsof most ec-trices are closest o Pale Horn (color #92); thoseof the central rectrices are closer to Salmon(color #6). Outermost rectrix on each side hasthe outer web almostentirelypale, with a darksubterminal atch 26 mm in length)on the n-ner web.Thepale outerwebof the outer ectrix,in combinationwith the pale base o the rectri-ces and the pale terminal fringe, isolateandoutline he dark centralpanelon the undersideof the tail.


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January 001] NewFlycatcherromCerrado egion 63Mato Grosso, seven males and six females(MPEG 54875 to 54884, AMNH 33100, 33131,and 33133); Maranho, one male and five fe-males (FMNH 63431, 63432, 63434; MPEG43526 to 43528); Minas Gerais, one male andtwo females (MPEG 36210, FMNH 56657,LACM 40086); Tocantins, one male (LACM46005);Cear, one male (USNM 264644);PiauLone unsexedspecimen MPEG 50917).Bolivia,depto. Santa Cruz, three males (LSUMZ124634, 124642, 150872). Of these, six malesand four females MPEG 54875 to 54884) werecollectedby us in Mato Grosso,Brazil.Suiriri suiriri bahiae:Brazil Bahia, one maleand two females (LACM 37067 and 37068,FMNH 64119).Suiriri suiriri suiriri: Argentina, Entre Rios,seven males, five females, and one unsexedspecimen YPM 66068 to 66073 and 83326, CM140482, 140489, 140490, 140670, 140806, and140867); Misiones, five males and five females(LSUMZ 56714 to 56723); Tucuman, threemales, our females,and two unsexedspeci-mens (FMNH 58012, 58019, 58369, and 58377;USNM 284898, 285001, 285002, and 285109;YPM 24195);La Pampa,one male and two fe-males (USNM 284329, 284332, and 284335);Chaco, one male and one female (USNM284330 and 284334); Buenos Aires, two males(USNM 55681 and 55683);Salta, one male (CM45839); and Santiago del Estero, one male(MVZ 108323). Bolivia, Santa Cruz, 18 males,14 females, and 1 unsexed specimen (CM119820, 120212, 120213, 32786, 32787, 32831,32889, 32891, 32952, 51402, 78970, 79244,80363, and 80364; FMNH 181493, 181502,181506, 294367, 295413, 296295, 296298,296301, 335151, and 335152; LSUMZ 124633 to124637, 153757, and 153758; YPM 31816 and31817); Tarija, five males and three females(ANS 138951, 138952, 138954, 138955, 138958,and 138959; FMNH 294369 and 294370); Co-chabamba, ne male and two females FMNH181498 and 181500;ANS 136168). Paraguay,depto. Presidente Hayes, two males (MVZ168120and 168121);depto.Chaco, our males(FMNH 153007, 153010 o 153012).Brazil MatoGrosso do Sul, one male and two females(FMNH 64121 to 64123); Parana, one male andone emale USNM 16367and 16368).Uruguay,RepresaPalmar, one male (ANS 187738).Specimens xamined:Tape recordings.--Datafor recordings reproduced as sonogramsare

provided n the correspondingigure egends.All recordingsby Kevin J. Zimmer unlessoth-erwise indicated. Suiriri islerorum: Brazil, MatoGrosso,westof ChapadadosGuimaresalongthe road to Agua Fria, 20 specimens,ndCox-ipo do Ouro road near Cuiab, 8 specimens;Amazonas,160 km E-SE of Humaita, 1 speci-men (M. Cohn-Haft).Suiririsuiririaffinis:Bra-zil, Amap, 12 specimens; ois, 2 specimens(A. Whittaker);Mato Grosso,westof ChapadadosGuimaraes long he road to Agua Fria, 4specimens, nd Coxipo do Ouro road near Cu-iab, 24 specimens. olivia, depto.SantaCruz,1 specimen T. A. Parker,LNS 52044). Suriririsuiriri bahiae:Brazil, Pernambuco,near LagoaGrande,16 specimens. uiriri suiriri suiriri:Ar-gentina,Salta, hree specimensS. Hilty). Bo-livia, depto. SantaCruz, one specimen T. A.Parker,LNS 33629).Brazil, Rio Grande do Sul,one specimen (W. Belton, LNS 19531). Para-guay,ChacoProvince, nespecimenD. Finch,LNS 57891).Etymology.--Weake great pleasure n nam-ing thisspecies fterour good riendsand col-leagues,Morton and Phyllis sler, in recogni-tion of their numerous contributions toNeotropicalornithology.Mort and Phyllisau-thored a landmark monographon tanagers(Isler and Isler 1987),and they have madepi-oneering ontributionsn developingmethod-ologies or the analysisof vocal charactersoassess peciesimits in antbirdsand othersub-oscines (Isler et al. 1997, 1998, 1999). Theirwork on antbirdshasserved o heighten ware-nessof the importanceof vocalizations s tax-onomic haractersn all suboscine roups, ndas such,has far-reachingmplicationsor theaccurateassessment f regional endemismandbiodiversity,and, ultimately, for conservation.The Islershavecontributed reatly o our ownstudiesof Neotropicalbirds, and are constantsourcesof advice, encouragement, nd help.TheEnglish amecallsattentiono the ype o-cality, he ChapadadosGuimares,Mato Gros-so, Brazil, which s an important eservoirofthreatened cerrado flora and fauna.

REMARKS

Sexual imorphismndvariationn the ypese-ries.--The type seriesof Suiriri islerorum on-sistsof 23 adult specimens6 males,16 females,and 1 unsexedspecimen).Males resemble e-


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64 ZIMMER,WHITTAKER,NDOREN [Auk, Vol. 118males, and plumage variation among para-types appears o be neithersexuallynor geo-graphically influenced. There is someindividual variation n color of the uppertailcovertsand in the extentof the contrastinglypalebaseof the rectrices. ompared o the ho-lotype, some ndividuals (MPEG 54872, LACM46004, LSUMZ 150871, AMNH 127882) aremore greenish-yellowclosesto Citrine, color#51) on the uppertail coverts, nother MPEG54870) was buffier, and two (MPEG 54871 andFMNH 63435)had the uppertailcoverts earlythe same color as the back. Two specimens(MPEG 54865 and LACM 40087) are more ex-tensivelygray dorsally,with the mantle andlowerbackmorenearlyconcolor ith thenape.Similar variation in rump-lower-back contrastwas apparentamong he 61 specimens f S.s.affinisexamined.Most observed variation among paratypeswas related to feather wear and molt condition.Most specimensre browneron the forecrownand grayer on the hindcrown,but a few aremoreuniformlygray hroughouthe crown. n-dividual feathers of the forecrown have abrownish ongitudinalstreakalongthe shaft,and are gray around the fringe. When thosefeathers re worn, he extentof thegrayrelativeto the brownish central streak is reduced, andthe forecrown ssumes morebrownish inge.Freshly molted birds had grayer forecrowns.Similarly,variation n the breadth of the paleterminal fringe to the rectrices, he buffy tipsof the secondary overts, nd the pale edgesofthe remigesall was nfluenced y wear.One male specimen MPEG 54871) had anunusually ong tip (hook) o the maxilla. Theculmen measurement for that bird was 8.52mm, but without the tip the culmen wouldmeasure 7.64 mm. In general, males wereslightly arger han emales, lthough ill mea-surementswere nearly identical Table2).Breedingndmolt.--Tenof the 23 specimensof Suiriri islerorum MPEG 54865 to 54874) werecollected from Mato Grosso, Brazil between20-22 September 999. All had enlarged go-nads, and two females (MPEG 54866 and54872)had well-developed rood patches. llwere vocal and territorial. Most birds showedsignsof moderateo heavywear of the second-ary coverts nd rectrices. imilarly, he FMNHspecimenrom Maranhfiowascollected Sep-tember 1925, and showedmoderate o heavy

wear. We believe that all of those birds were inbreeding condition.We never have observedfamily groupsof S. slerorum uring our Augustand September isits to Mato Grosso.That,combinedwith the apparentbreeding eadi-ness and territorial nature of the birds we col-lected n lateSeptember,uggestshat hemainhatching nd ledgingperiod s probablyn Oc-tober.That would fit a commonpattern or in-sectivorous irds n regionswith pronounceddry seasons,n which hatchingcoincides ithonsetof the rainy season nd the concomitantflush of insect populations Walsberg1977,Marr 1981, Zimmer 1993).The four AMNH specimensrom Mato Gros-so were collectedbetween 7 February and 26May. All had remigesand rectriceshat wereless worn and more broadly pale-eged orfringed than in our specimens. imilarly, hethree LACM specimensrom Gois and Tocan-tins were collected etween14 April and 3 May,and all were n fresherplumage hanourseriesfrom Mato Grosso. he ANSP specimenANSP159808)was collected30 Juneand was n freshcondition. The LSUMZ specimen (LSUMZ150871) was collected29 August, and was infresh condition with a trace of molt on the headand with an ovary that measured6 x 7 mm.The condition f thosespecimensuggestshatS. slerorurnndergoesone molt sometime fterbreeding n September o October,and thenprobably undergoes at least a partial moltagain in spring or summerprior to the nextbreedingseason.Vocalizations.--Male and female Suiriri isle-rorumhavedifferent oudsongs, hichare typ-ically delivered as sex-specific lementsof si-multaneous duets, but are occasionallydeliveredseparately. he male loudsong Fig.3A) is a loud seriesof paired couplets, ll noteshaving a distinctly wangy quality.The songhas wo discernible hraseshatarerepeatednpredictable atterns wherewhere, hoozt whoozit, where where whooz t, whooz it, whooz t, whoozit). Sometimes males will sing a series of"whooz it" notes without the "where where"notes. The number of consecutive "whooz it"couplets may vary from two to six (rarelymore), but no more than one "wherewhere" ou-plet seems o be givenwithout nterjectinghe"whooz it" notes. In response to playback,males requentlysing ongersongs. he mostcommonlyheard male calls are isolatednotes


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January 001] NewFlycatcherromCerradoegion 65MALE6

Suiriri islerorum

432

' 1o 0

"' 7

A loudsong B calls

i i i i i i i i i0.5 I .0 I .5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

FEMALEC loudsong D "wheer-deer"

..

E "zhuwheep"zhuwheep-oo"

i i i i i i i i0 0.5 I .0 1.5 2.0 2,5 3.0 3.5 4.0 4.5 5.0

Time (seconds)FIG. 3. Vocalizationsof Suiriri islerorumecorded from Mato Grosso MT), Brazil. MPEG numbers n pa-renthesesmatch ape recordingswith specimensn the MuseuParaense milio Goeldi,Be16m, ar , Brazil.(A) Male loudsong MT, near Cuiab& 22 September 999). B) Male (MPEG no. 54874)calls MT, Chapadados GuimarSes,21 September1999). (C) Female oudsong MT, near CuiabJ, 22 September1999). D) Female

(MPEG no. 54872) "wheer-deer"all (MT, Chapadados GuimarSes, 1 September 999). E) Female zhu-wheep" nd "zhuwheep-oo"alls (MT, near CuiabJ, 22 September1999).All recordingsby Kevin J. Zimmer.or couplets imilar o thosegiven n loudsongs(Fig. 3B). The female oudsong Fig. 3C) is aloud,bubbly attleof variable ength hat s typ-ically precededby one or two well-differenti-ated "whur" or "wheer"notes. n response oplayback, emales ypically engthen he rattleelement f their songs. emales ommonly ivetwo types of calls. The first is a series of"wheerDEER"alls Fig.3D) that aresomewhatsimilar o the male couplets, ut that are moreemphaticparticularlyon the second yllable),with a less wangy, essstridentquality,whichare frequently nterjected nto duets.Outsideofduets, he mostcommonly eard femalecall sa querulous ounding, wo-or-three-syllabled"zhuwheep"r "zhuwheep-oo,"n which he ongfirst note is diphthongaland distinctlyup-ward-inflected at the end, and the second,shorternote,whenpresent, rops n frequency(Fig.3E).That call s typicallygiven n thecon-text of a contactcall when a female s visuallyseparatedrom her mate. n duets Fig. 4), themale and femalesing heir oudsongs imulta-neously, reatinga somewhat iscordantum-

ble of notes, with the female rattle and thetwangy male notesequallydistinct.As with S. islerorum, the male and femaleloudsongsof S.s. affinisare most commonlyheard as sex-specificlements f simultaneousduets,but are sometimes eliveredseparately.The male loudsongof S.s. affinis s a seriesofsneezy pi-chew" otes, ariable n length, hattypically begins with severalsqueaky ntro-ductory notes and ends with severalone-syl-labled"chew"notes Fig. 5A). The female oud-song Fig. 5B) is a seriesof loud, squeakynotesthat typicallydeceleratesoticeablyoward heend. Thosenotesare similar n quality to theintroductory otes n malesongs, ut arehigh-er frequency,higher amplitude, and morewidely spaced.The terminal notes n a femaleloudsong often drop in frequency. Femaleshave a variety of single-notecalls, most ofwhich are nasal and have a distinctlywhinyquality Fig.5C,D). Those reroutinelyutteredascontact alls,butwhena femalegivesseveraldifferentiatedwhiny calls n rapid succession("suiree,swee, wiroo, hew") t is usually the


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66 ZIMMER,WHITTAKER,NDOREIN [Auk, Vol. 118

lO8642o

Suiriri islerorumA male/female duet

0

B male/female duet

8 C male/femaleuet!

.. , '...',...., ....... ..............

10.0

i i i i i i i i i0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0

Time (seconds)FIG. 4. Male-female duets of Suiriri islerorum recorded from Mato Grosso (MT), Brazil. MPEG numbersin parenthesesmatch ape recordingswith specimensn the Museu Paraense milio Goeldi, Be16m, arfi,Brazil. (A) male-female (MPEG nos. 54865and 54866) duet (MT, near Cuiabfi, 20 September1999). (B) Male-female (MPEG nos. 54874 and 54872) duet (MT, Chapada dos Guimarfies,21 September1999). (C) Male-female MPEG nos. 54869and 54867)duet (MT, Chapadados Guimarfies, 1 September 999).The femalefrom this pair (MPEG no. 54867) s the holotype or the species. ll recordings y KevinJ. Zimmer.

synchronizingue hatbegins duet.A female,whosemate we had collected, epeated hosesingle-note asal calls for more than an hourafterwards. The most frequently heard malecall outsideof a duet context s a single-note,somewhat uttural "werk" (Fig. 5E). Lesscom-monly heard s a low-frequency attle that mayfunctionas an aggression all (Fig. 5E G). Wehave heard that call given several imes frombirds of unknown sex within foraging amilygroups,as well as from a female that was at-tempting to aggressively displace a LesserElaenia (Elaeniachiriquensis)rom a fruitingtree. n duets Fig. 6), the higheramplitude e-male loudsongs end to mask the male loud-songs. he similarityof the femalenotes o theintroductory male notes makes it even moredifficult to distinguish he full male song.All vocalizationsof S.s. bahiae ppear to behomologouso the vocalizations f S.s. affinis.

The male loudsong f S.s. bahiae eginswith arapid series f squeaky, omewhatun-togethernotes hat drop n frequency eforeyielding oa distinctive series of "pitty-chew" elements(Fig. 7A). The introductoryseriesrecalls hesounds hat would be madeby squeezing toyrubber duck several imes in rapid succession.The female loudsong Fig. 7B) is a seriesofsqueaky "choop" notes (peak frequency ofabout 8 kHz) delivered at about 8 to 10 notesper second.Thosenotesare similar in tonalityto those hatprecede he "pitty-chew"lementsin the male song,but are higher in frequency,more widely separated,and do not drop in fre-quencyhrough heseries.Bothsexes ive heirrespective songs during simultaneousduets(Fig. 6D). In duets, he female oudsong s typ-ically louder than that of the male. A singleduet bout might include two or more songsfrom eachbird, with the final female song n


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January001] NewFlycatcherromCerradoegion 67the bout often decelerating oticeably owardthe endof the song.The terminalnotes n sucha deceleratederies re ower n frequencyhanthe introductorynotes.Males frequentlycon-cludeduetswith a few sputtering pitty-chew"calls. Outside of duets, the most frequentlyheard male call is a guttural, singlenote (Fig.7C). Thiscall apparently unctions sa contactcall.The seriesof "pitty-chew" allsalso s fre-quentlygiven ndependent f the squeaky re-lude (Fig. 7D), particularly n duets.The mostcommonly eard femalecall is a nasal"nyew"with a distinctlywhiny quality.Those allsaretypicallydelivered ingly n the context f con-tactcalls,but theyalsoareoftenstrung ogeth-er in rapid successionFig. 7E), particularly bybirds agitated by tape playback. Femalesre-sponding to playback typically begin givingthosewhiny notes n flight as they approachthe sound ource. s in S.s.affinis, rapidlyde-livered seriesof those emalenotes ollowingplayback ppears o be the synchronizinguethatprecipitatesheresponsorialuet rom hepair The only vocalizationof S.s. affinis orwhich we could ind no homolog n S.s. bahiaewas he rattlecall (Fig.5EG). The apparent b-senceof sucha vocalization n S.s. bahiaemaybe an artifact of sampling,because attle callswere only occasionally ecorded from S.s.affinis.Our inventory of tape recordingsof nomi-nate S.s. suiriri s small.What appears o be aloudsong n Argentina (Fig. 8A) is a long (3 to5 s), frenetic,sputteringseriesof nasal notesthat rise and fall in frequency, ith occasionaldifferentiated querulous notes scatteredthroughthe middle. We do not know if thisloudsong s specific o one sex, and, if so, towhich one. The most common vocalization is asinglenasal"row?'or "jyow"note that is re-peated ncessantly or prolongedperiods.Mi-nor variations of this call lave been recordedfrom Argentina, Brazil, Bolivia, and Paraguay(Fig. 8B-E). Anothercall recorded rom Para-guay s a 2-3 s rattle at about5-6 kHz (Fig. 8F).Duetdisplay ehavior.--The oststrikingbe-haviors of S. islerorum were those associatedwith territorialduetsof matedpairs Fig.1 andcolorplate).Pairswere tightly synchronizedntheir duets. The first few notes of either a maleor female loudsongwere enough o initiatemostduets,with the second ird joining n im-mediately.Prior to singing, pairs typically as-

sumeda prominentperch n the crownof a treeor on a baresnag,usuallywithin 0.5 m of oneanother Duets were always accompanied ydramatic, sex-specific, tereotyped motions.The male flickedboth wings high abovehisback (the wings nearly touching)at a rate ofabout one per second or the duration of theduet (6-10 s). With each downstroke of hiswings,he flippedhis tail upwards,at abouta45 angle.When the wings were once againflickedupwards, he tail was flipped down 30to 45below he horizontal.During the display,the male eaned orward,so hat his rump washeld at about he sameplane as his head. Thetail was anned hroughoutmuchof the display,emphasizinghe contrast etween he yellow-ish-buff base and the blackish distal half. Somemales rotated at approximatelya quarter turnwith eachup-and-down ycleof the wingsandtail, such hat they were constantlyurning ncircleswhile displaying. imultaneousith themale'sdisplay, he femalealso aisedher wingshigh aboveherback,but held hem here, ully-fanned, for about 2-3 s at a time before lower-ing them gradually.Femalesepeated hat mo-tiontwo or three imesduringeachduet.At thesame ime that a femalewasraisingher wings,shewould also an and dip her tail downwardat a 20 to 45angle, lipping he tail backup tothe horizontalpositionas he wingswere ow-ered.The fanningof the wingsby females c-centuated he largely pale inner webs of theremiges such that backlit birds appeared tohave ranslucent ings.Females lso requent-ly rotatedwhile displaying, ut were ess ikelyto do so than the frenetic males. Females alsomaintained moreuprightposture hroughouttheir displays. hosedisplays f S. slerorumc-companiedeach of the more than 200 duetbouts hat we witnessed, nd are remarkablysimilar to thoseof the Streamer-tailed yrant(Gubernetesetapa) f southernSouthAmerica,and, to a lesserextent,of White-bearded ly-catcher Phelpsianornata) f Venezuela K. Zim-mer pers. obs.).We never have witnessedsimilar displaysfrom eitherS.s. af,inisor S.s. bahiae,n spiteofhaving witnessedmore than 200 duetsof theformer and more than 100 duets of the latter.Sick 1993)describedhe songof S.s. affinis s"repeatedwhile lifting bothwingsvertically."That description lmostcertainly s baseduponobservations f S. slerorum. uiriri s. af,inisand


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68 ZIMMER,WHITTAKER,NDOREIN [Auk, Vol 118

Suiriri suiriri affinis5-4-3-2-10

0

10

A male oudsong. intro

I

.

"pl-chew" lements

i i i iI .0 I ,5 2.0 2.5

"chew" notes

i i i3.0 3.5 4.0 4.5 5.0

9-8-7-6543

B femaleoudsong

I I I I I0 0.5 I .0 I .5 2.0 2.5

i i i i3,0 3.5 4.0 4.5 5.0

543210

C femalewhiny"alls

i i i i0 0.5 I .0 I .5 2.0 2.5

D female whiny" alls

3.0 3.5I I

4.0 4.5 5.0

6-5-43210

male guttural"all F female rattle call.

I I I I0 0.5 I .0 I .5 2.0

G rattle call

i i i 2.5 3.0 3.5 4.0 4.5 5.0

Time (seconds)FIC. 5. Vocalizationsof Suiriri s. affinis rom various sites n Amap (AP) and Mato Grosso MT), Brazil.MPEG numbers n parenthesesmatch ape recordingswith specimensn the MuseuParaense milio Goeldi,Be16m,Par, Brazil. (A) Male (MPEG no. 54881) oudsong MT, near Cuiab, 22 September 999). B) Femaleloudsong MT, near Cuiab, 21 September1998). C) Female"whiny" calls MT, near Cuiab, 22 September1999). (D) Female"whiny" calls (AP, north of MacapP, 12 February 1999). (E) Male guttural call (MT,


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January 001] NewFlycatcherromCerrado egwn 6910 Suiririuiririf.inis

10

A male/female duet.

female"whiny"callsmale/femaleoudsongs

i i i0 JO 8' 9'1.0 2. 3;0 4.0 5.0 6 7:0 .0 .0Sui suid affinb

10.0

86

B male/femaleduet male/femaleoudsongsfemalewhiny"alls , }

....i i i i i i0 i i i.0 2.0 3.0 4.0 5.0 6. 7.0 8.0 9.0

Suiriri uiriri fJnis10.0

male/female uet male/femaleoudsongsfemalelwhiny"alls

I i i i i i i i i1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0

1 0 Suiririuiriri ahiae10.0

D male/femaleduet

o lO.O

female whiny" all femaleoudsong male oudsong

I I I I I I I I lI .0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0

Time (seconds)FIG.6. Male-femaleduetsof Suiriris. affinis nd S.s. bahiaerom various ocalitiesn Amap (AP), MatoGrosso MT), and PernambucoPE)Brazil. A) S.s. affinisrom ChapadadosGuimarfies,MT (21 September1999). B) S.s.affinis rom ChapadadosGuimarfies,MT (21 September 999). C) S.s.affinisrom nearPortoGrande,AP (7 February1999). (D) S.s. bahiaerom Lagoa Grande, PE (15 January1997).All recordingsbyKevin J. Zimmer.

S.s. bahiae exhibited identical behaviors whendisplaying.Duets almostalwayswere initiatedby severalnasal, single-note emale calls (Fig.6A-D) given in rapid succession.f the malewas in a different ree or anotherpart of thesame ree,he would rapidly fly toward the fe-

male, and next to her, and then he pair wouldsimultaneouslysing their respective oud-songs. he postureof both birds during duetswasnearlyhorizontalwith thewings ypicallydrooped slightly at the sides.Birds usuallyquivered heir wings slightly while keeping

ChapadadosGuimarfies, 1 September 999). F) Rattlecall from female MT, near Cuiab, 22 September1999). G) Rattle call of bird of unknownsex (AP, north of Macap& 12 February1999).All recordings yKevin J. Zimmer


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70 ZIMMER,WHITTAKER,NDOREN [Auk, Vol. 118Suiriri suiriri bahiae

A maleoudsong-4-

2

0o

lO0.5 1. 1. 2.0 2.5 3.0 15 5410 4. 5

9-8-7-6-543210

B femaleoudsong

0 i '1 i i i i i i.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4,5 5.0C male guttural"all D male pitty-chew"

' '0 ' ' 5 '0 ' ' '0.5 1. I .5 2.0 2. 3. 3.5 4.0 4.5 5.07-6-5-4-3210

E female whiny" alls

0 0.5 1. 1.5 2. 2.5 3.0 3.5 4.0 4 5 5.0Time (seconds)

FIC. 7. Vocalizations f Suiriri s. bahiaeecordednear LagoaGrande,Pernambuco, razil. (A) Male loud-song (25 January1999). B) Female oudsong 25 January1999). C) Male guttural call (25 January1999). D)Male "pitty-chew"alls 25January 999). E) female whiny" calls 25January 999).All recordings y KevinJ. Zimmer


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January 001] NewFlycatcherrom Cerrado egion 71Suiriri suiriri suiriri

7-6-543210

A presumedoudsong

..... '"..............................i i i i 15 i i i i.5 1.0 1.5 2.0 2. 3.0 3.5 4.0 4.5 5.0

B single-noteall

I0 0.5

C single-noteall

i1 0 1.5 2

D single-noteall

0 2.5

E single-noteall.; '. -...

..'..'.I

F rattle call

.

0 i ) i i i i i i i0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0Time (seconds)

FIG.8. Vocalizationsf Suiriris.suiriri. A) loudsongArgentina, alta, October 987;S. Hilty record-ing). (B) Single-noteall (Argentina, alta,6 October 987;S. Hilty recording).C) Single-noteall (Brazil,RioGrande oSul,50kmsouthwestanto ntonio asMiss6es,November975;W.Beltonecording,NS19531). D) Single-note all (Bolivia,depto.SantaCruz, west of San sidro, 6 October1983;T. Parker ecord-ing, LNS 33629). E) Single-noteall (Paraguay, hacoProvince, iladelfia, 1 August1990;D. Finch ecord-ing, LNS57891).F) Rattle all Paraguay,haco rovince, iladelfia, 1 August 990;D. Finch ecording,LNS 57891).

themdrooped, nd sometimesimultaneouslyshivered he tail up-and-downn a shallowarcof less han5.UnlikeS. sIerorum,either ffinisnorbahiaeabitually elected rominent erch-es from which to display,and often duettedfromwithin thecanopy f trees.Birds espond-ing to tape playbackoften sangas they wereflying toward he soundsource, behavior hatwe did not observe in S. isIerorum. On severaloccasions e had affinismales hatwere sepa-rated from their mates espond o tape play-

backby flying n and perching earus withoutvocalizing. Even after leaving and beingbroughtback by tape playback wo or threetimes, hosemaleswouldnotsingon heirown.In each ase, female ventuallylew n givingseveralnasalcallsand the pairs immediatelybegan o duet.Tapeplaybackxperiments.--Playbackxperi-mentswith Suiriri ecordings ffer urtherev-idenceof the significance f vocal differencesamong he taxa,and of their role as potential


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72 ZIMMER, HITTAKER,NDOREN [Auk,Vol. 118TABLE . Summaryof playback rials (asdetailed n the text) nvolvingSuiriri lycatchersS. slerorurn,.s.affinis, .s.bahiae nd S.s.suiriri).Numbers n parenthesesndicate he numberof pairsor family groupsof the subject axon hat were tested or eachstimulus axon.

Response o playback ofLocality islerorum affinis bahiae suiririS. islerorum

Mato Grosso,Brazil strong 11) none (11) none 11) none 6)S.s. affinisAmapa, Brazil none 3) strong 3) strong 3) none (2), moderate 1)Mato Grosso,Brazil none 12) strong 12) strong 12) --Totals none (15) strong 15) strong 15) none (2), moderate 1)S.s. bahiae

Pernambuco, razil none 5) strong 5) strong 5) none 3), strong 2)

isolating mechanisms.We performed tapeplaybackexperimentson 11 pairs of Suiriri is-lerorum ear Cuiaba and ChapadadosGuimar-aes,Mato Grosso,Brazil (six pairs in Septem-ber 1998and five pairs n September 999).Thesix pairs n the 1998 rials werepresentedwithrecordingsof S.s.bahiaerom Pernambuco, ra-zil, S.s. affinis rom Cuiab, Mato Grosso,Bra-zil and S.s. suiriri from Argentina. The fivepairs n the 1999 rialswerepresentedwith thesame ecordingsof S.s. bahiae nd S.s. affinis.None of the 11 pairs tested showedany re-sponse o tape playbackof suiriri,affinis, r bah-iae vocalizations.When presentedwith play-back of prerecordedS. islerorum ocalizations,all 11 pairs responded by immediately ap-proachinghe sound ource ndduettingmul-tiple times. n severalcases, hosebirds flew infrom >100 m away when responding o play-back of their own vocalizations.

We performed ape playbackexperimentson12 pairs or family groupsof S.s.affinisnear Cu-iaba and ChapadadosGuimaraes,Mato Gros-so,Brazil (six pairs in September 998and fourpairs and two family groupsof four in Septem-ber 1999).Birds in all 12 trials first were pre-sentedwith taped vocalizations f S. islerorumfrom Chapada dos Guimaraes, then with re-cordingsof S.s. bahiaerom Pernambuco,Bra-zil. Noneof the 12 pairs or family groups e-sponded to playbacks of vocalizationsof S.islerorum, ut all 12 pairs of adults respondedstrongly to playback of S.s. bahiae ocaliza-tions.We alsoperformed ape playbackexper-iementson two family groupsand one pair ofS.s. affinisnorth of MacapP, Amap, Brazil(February1999). Those birds first were pre-sentedwith playback f S. slerorumecordings,

to whichnoneof them esponded.We henpre-sented hem with playbackof nominateS.s.suiriri rom Argentina.The adult pair from thefirst family group responded y approachingthe soundsource ndpeeringabouton two oc-casions, but did not vocalize. None of the fourbirds rom the other amily groupshowed nyinterest n playbackof nominateS.s.suiriri, nordid the onepair.Whenpresented ith tapeofS.s. affinis rom Mato Grossoand S.s. bahiaefrom Pernambuco,ll threepairs of adult S.s.affinis rom Amapa responded tronglyby ap-proaching nd duetting.In January 999,we performed apeplaybackexperimentson five pairs of S.s. bahiae ear La-goa Grande,Pernambuco, razil. Thosebirdswere first presentedwith taped vocalizationsof S. islerorum from Mato Grosso, Brazil. Noneof the five pairsshowed ny responseo thoseplaybacks. e thenpresentedhemwith play-back of S.s. affinis rom Mato Grosso.All fivepairsresponded trongly o playbackof S.s.af-finis,alwaysapproachinghe soundsource ndduettingby the fourthplayback.We alsopre-sented he ivepairsof S.s.bahiae ith playbackof nominateS.s. suiriri from Argentina.Threeof the pairs did not respond o the voice ofnominate irds.The other wo pairsrespondedstrongly (approachand vocalizations), ut itshouldbe pointedout that they wereprevious-ly stimulated y tape of affinisrom Mato Gros-so.The resultsof thoseplayback rials are sum-marized in Table 3.Foraging ehavior nd socialstructure.--Suiririislerorumypically was encounteredn closelyassociatedairs,apart rom otherspecies. heyforagedmostly n trees (rarely descendingolow shrubsor the ground),movingenergeti-


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January 001] NewFlycatcherromCerradoegion 73cally with shortpauses etweenhopsand fre-quent and erratic changes f direction.Theygleaned arious mallarthropodprey rom eafand branchsurfaces.Once prey was spotted,they frequently used wing-assistedhops toclosedistance apidly, hen unged orward ora horizontal capture,or jumped upward togleana prey tem from overhead. heyalsoen-gaged n frequentdarting aerialsalliesupwardor outward to glean prey from undersidesofleaves or branches. Those sallies varied from 15cm to 1 m and typically nvolved ittle truehov-ering. Thosebehaviorswere similar to that ofmembersof the generaTolmomyiasnd Platyr-inchus, lthoughS. islerorum ere more con-stantly n motion and were more agile and ac-robatic in pursuing prey (K. Zimmer pers.observ.).Suiriri islerorumalso made occasionallonger up to 2 m), loopingsalliesoutfrom thecrown or lateral branches of trees and back topursue lying nsects. erch hanges ereusu-ally followedby an obvious,but relaxeddown-ward dip of the tail, similar to tail movementsof VermilionFlycatcherPyrocephalusubinus).Suiriris. affinisn the sameareas requentlyperch-gleaned r hover-gleaned mall fruits(particularly hoseof Curatella mericana),l-though hey spentmore time in pursuit of ar-thropods.Suiriris.affinis oragedmostly n rel-ativelyopen rees,progressing y hopsof 5 to15 cm, primarily alongmain branches. heirmovementshrough reeswere generallymoreleisurely n pace (almost Vireo-like)and morepredictablen progressionhan n S. slerorum.Birds paused or 2-15 s betweenhops o scanlive foliage, fruit clusters,or bark surfaces.They generallyworked rom the interior of atree outward, or from the subcanopy p, butwithout frequentchanges f directionas n S.islerorum. rthropodprey usually -75% of allcaptures)were gleaned directly from leaf orbranchsurfaces y reachingout, up, or down.Foraging irds oftenpickeddirectlyat branchsurfaces, articularly on trees with furrowedbark. They also requentlyhover-gleanedreyby hovering1-2 s beneathgreen eaves n theouterportionof the canopy. hatwasdifferentfrom the darting sallies with little or no truehovering)madeby S. slerorum. uiriri s. affinisoften dropped 1-3 m from branches o theground o pounceon prey spotted rom above.That behaviorwas particularlycommon n re-centlyburned or very openareas,and wassim-

ilar to foraging echniquesoutinelyemployedby bluebirds Sialiaspp.;K. Zimmer pers.obs.)in North America.Suiriris.affinis lsomadeoc-casionalshort, looping sallies of 1-2 m outfrom crowns of trees in pursuit of flying in-sects, ut that behaviorwas ess requent hanin S. islerorum. ike S. slerorum, ffinisperiodi-cally wagged its tail downward in a relaxedmannerwhen oraging,particularlyafterperchchanges. oragingbehaviorof S.s. affinisob-served n Amap, Brazil was identical o thatdescribed above from Mato Grosso.

The social structureof S. islerorumequiresfurther investigation.We have never encoun-tered more than two birds together.However,in September1999, we had two experiencesthat suggest hat S. islerorums at least occa-sionally polygynous. On 21 September1999,we taped a pair of S. islerorum long he AguaFria Road, Mato Grosso,Brazil. After obtainingvoucher apes,we collected he displaying e-male (MPEG 54867).The male flew a short dis-tanceout of sight. mmediately fterretrievingthe female,we broadcastmore tape playbackfrom the samespot, and a male returned.Assoon as the male perched n front of us, a sec-ondbird flew nto thesame reeandsanga typ-ical female loudsong.The male immediatelychased that second female, pursuing heraround reesand shrubs.This wasrepeatedonfive occasions; ach time we presented apeplaybackof duets the male would approach,followedclosely y thesecondemale,whichhewould then aggressively rive off. Only onceduring those encounters id the two birdsduet. On our last playbackattempt, the maledrove the female to the groundand appearedto mounther. They then flew to a nearby reeand performedmore duetsbeforewe collectedboth birds (male MPEG 54869, second emaleMPEG 54868). Gonadsof all three birds wereenlarged.Later on 21 September,we were collectingfarther along the Agua Fria Road when wetaped in another pair of S. islerorum.Onceagain,we collected he female (MPEG 54872)first, and the male flew off. After a few minuteswe presentedmore playbackof duet vocaliza-tions. Immediately,a pair of S. islerorumlewinto the same tree from which we had collectedthe female, and proceeded to duet multipletimes. After obtainingvoucher apes,we col-lectedboth birds (second emale MPEG 54873,


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74 ZIMMER,WHITTAKER,NDOREN [Auk, Vol. 118male MPEG 54874).The first femalehad a con-spicuousbrood patch and the gonadsof allthreebirds were enlarged.In each of those instances, what we assumedto be the originalmale appeared o return witha secondadult female in breeding conditionwithin 5 min of the time that we had collectedhis previousmate,which suggestshat thosemaleshad beenmated o two birds all along. tseems ighlyunlikely hat more han onemalewas involved in either case. There was no evi-denceof a seconderritorialmaleor pair in thevicinity prior to collection f the first females.Had we been at a boundary between two ter-ritories, t seems ikely that our tape playbackwouldhaveelicited esponsesrombothneigh-boringpairs. nstead,playbackbroughtan im-mediate approachand duet response rom asinglepair. Followingour collection f the fe-male of eachpair, the respectivemales lew offout of sight,after which a male flew back romroughly the same area minutes later in re-sponse o further playback.Birds respondingto the secondoundof tape playback erchedin the sameor adjacent hrubs s hoseusedbythe birds responding o the first tape play-backs.We haveonly rarely foundpairs of S. s-lerorum ccurring n closeenoughproximity ooneanother hat we couldhear (evendistantly)two pairs from a single spot, making it evenless likely that two independent territorialpairswere nvolved n each nstance.Systematic elationships.--Someeneraliza-tions regardingrelationships mong he yel-low-belliedgroupof Suiriricanbe made.Suiririislerorums sufficientlydistinct to be consid-ered a separate pecies nderany of the widelyaccepted pecies onceptsMcKitrick and Zink1988). Vocal distinctions are particularlystrong.Suiriri slerorum iffersstrikingly romnominatesuiriri, affinis,and bahiaen its maleand female oudsongs, uets,and n all knownmale and female calls. Duets serve multiplefunctions, ncluding coordinateddefenseofterritory and pair-bonding. n Suiriri, as n themajorityof duettingspecies,he same ypesofduets are used during boutsof territorial de-fense, as a prelude to copulation,and whenpairs reunite followingvisual separation Far-abaugh1982,K. Zimmer pers.observ.).n sex-ually monochromaticpecies Suiriri), sexualspecificity of duet contributions probablyserves in mate attraction as well as in identi-

fying the sexof a territorial resspasserFara-baugh1982).A likely byproductof sexualspec-ificity of duet roles is the strengthening freproductive solation. n an habitually duet-ting genus uch sSuiriri,vocaldifferencese-tween taxa would seem o presentmajor obsta-cles to reproductive compatability.Furtherbarrierswould be presented y significant if-ferencesn stereotyped hysicaldisplaysas-sociated with the vocalizations. As detailedabove,pairs of S. islerorum erform distinctivedisplayswith eachduet.Nothing hat we haveheard or seen n the vocal and display reper-toire of affinis r bahiaeuggestsn approachoislerorum.

The biologicaland taxonomic ignificance fthosedifferencess suggested y the resultsofour playbackexperiments.Althoughwe wereunable o perform all pairwise tests, he onesperformedwereunequivocal. oneof the affin-is or bahiaeested showedany response o re-peated playbacksof islerorum, or did any ofthe islerorumespond o playbacks f the othertaxa.

Morphologicaldifferences rom affinisandbahiae re subtle yet distinct, even when ob-served n the field.Among he eightcharactersthat were measured, Suiriri islerorum differedsignificantlyrom affinisn culmen ength,billwidth, bill depth, wing chord, tail length,width of the central rectrix, and width of thepale tip to the rectrices Table2). The two spe-ciesalsodiffered n the colorpatternof the out-er rectrices, and in whether or not the centralrectriceswerepale-edged.Our sampleof affinisindicatedsubstantial exualdimorphismn billsize and color of the mandible, whereas no suchdimorphismwas apparent n islerorum.t is notknown whether uvenilesof S. islerorumharethe unique spottedpattern to the upperpartsfound n juvenilesof other Suiriri.Most important, Suiriri islerorum nd S.s. af-finis are syntopic t multiplesites,andshownoevidenceof interbreeding.At the two localitiesin Mato Grosso, Brazil, where we conductedfield studies,both forms were relatively com-mon and all pairs of Suiriri were assortativelymated by vocaltype and morphologicalype(as confirmedby tape recordings,specimens,and tissuesamples). hus, they meet the pri-mary criteria for being considered pecies n-der the biological pecies oncept.


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January 001] NewFlycatcherromCerradoegion 75Finally, preliminary molecular analyses oftissue samples indicates that S. islerorum sstronglydifferentiated eneticallyrom both S.s. affinisand S.s. bahiaeJ. Batespers. comm.).

Those results will be presentedelsewhereaspart of an overview of genetic diversity inSuiriri.Basedon vocal similarities,S.s. affinisand S.s. bahiae learly are closely elated. The latterformresembleshe former n havinga longbilland yellow belly, but differs n being shorter-winged, showing little back-rump contrast,and in lacking he contrasting ale base o therectrices (Traylor 1982). However, our exami-nation of 61 specimens f affinissuggestshat

the degreeof back-rumpcontrast nd the ex-tent of the contrasting ale baseof the rectricesare individually variable characters, nd ex-tremeexamples f affinismay at leastapproachtypical examplesof bahiae.Hayes (2001) alsofound significantplumagevariability n speci-mens of bahiae.All vocalizationsof bahiae p-pear to be homologouso thoseof affinis, nddisplaybehaviors f duettingpairs are identi-cal. Furthermore, n reciprocal tape playbackexperiments, all pairs of bahiaerespondedstrongly o playbackof affinisvocalizations, sdid all pairs of affinis o vocalizations f bahiae.The relationshipof nominateS.s. suiriri tothe yellow-bellied forms remains uncertain.Nominate birds are strongly differentiatedmorphologicallyand vocally from islerorum,and in tape playbackexperiments, he latterspeciesdid not respond o playbackof suiririvocalizations. There is no reason to considerthem as anythingother han separate pecies.In the absence of contact, nominate birds alsowould appear o be sufficiently istinct rom af-finis and bahiaen bothmorphological nd vocalcharacters s to warrant separatespecies ta-tus. However, he statusof intergradesor hy-brids from the contact zone in northern Para-guay and southwesternBrazil remains anissue.Hayes (2001) found that presumedhy-brids rom the contact onehad plumagechar-acters ntermediatebetween suiriri and affinis,and exhibitedsignificantplumagevariability.The apparentscarcityof parentalphenotypesfrom within the contactzone suggested hatthe two forms were freely interbreeding, ndtherefore, onspecificHayes2001).Furtherun-certainty s introducedby our playbackexper-iments, n which somepairsof affinis nd bahiae

responded to suiriri vocalizations,whereasmost pairs showedno response.More compre-hensive nventoriesof tape recorded vocaliza-tionsof nominatebirds are needed or a propervocal analysis. Also needed are field studiesfrom the contact onebetween uiririand affin-is, as well as more extensiveplayback experi-ments ocusedon this pair of taxa. Molecularanalyses n progress (J. Bates et al. unpubl.data) also shouldclarify those elationships.Ecology nd conservation.--Suiririslerorumsa bird of the cerrado egion, a biogeographicregion that encompasses.5 to 2 million km2centered on the Brazilian shield, with exten-sions into eastern Bolivia and northeastern Par-aguay (Eiten 1972). The term "cerrado" hasbeen applied generally o virtually all of thenonforest abitats f thatregion,althoughgeo-graphically t variesgreatly n species ompo-sition and physiognomy.Five major subtypesof cerradohave been recognizedby botanists(Eiten 1972).Of those,we havefound Suiriri s-lerorum o occur n three: (1) cerradosensu tric-to, woodland with closed scrub and scatteredtrees; 2) campocerrado,more openscrubwitha few trees;and (3) camposujo,grasslandwithscattered hrubsand few trees. n the Chapadados Guimares and Cuiab regions of MatoGrosso,Suiriri islerorums locally fairly com-mon in someareasbut seeminglyabsent romothers.Moderatelyclosed,shrubbyareaswitha significant grass component and scatteredtrees2-5 m tall (asexemplified y the first sev-eral kilometers f the Agua Fria road nearCha-pada dos Guimares)have the highestdensi-ties of S. islerorum.Our limited surveyshaveaveraged1 to 2 pairs per kilometerof road, butmore extensivedawn surveysusing systematictapeplaybackundoubtedlywould yield higherdensities.The species s somewhat ess com-mon along the Coxipo do Ouro road near Cu-iab, where the habitat is more wooded withpockets f regularlyspaced rees closer o cer-rado sensustricto;Eiten 1972). Suiriri s. affinisoccursalongside slerorumn both areas,but ismore common in the more open woodlandsand less common n the shrubbier,grassiercerrado.

The areas in which we have found Suiriri is-lerorum re subject o regular human pertur-bation.The biggestdisturbance uring the ten-ure of our work has been fire. Accidental ordeliberatelyset fires have burned significant


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76 ZIMMER,WHITTAKER, ND OREN [Auk, Vol. 118

portions f cerrado long heAguaFria road nthree of the last five years, and have also af-fected he nearbynationalpark. Localpopula-tions of both Suiriri islerorum nd S.s. affinishavepersistedn heavilyburnedareas,but therepeatedburning of the same areaswithoutsufficient ime for recoveryof the shrub com-munity ikely will havea negative ffect.Hous-ing developmentsavespreadnto the cerradoalong the Agua Fria road, and continued x-pansionsoonwill threaten he type localityofislerorum.

On a broaderscale, he dry forestand grass-land habitats of central South America are con-sideredboth among he mostendangered ndunique biomes n the Neotropics Stotz et al.1996). The cerrado is especially hreatened,with more than 75% of the 41 endemic birdsconsidered at risk, and more than 45% consid-ered either hreatened r endangered Stotzetal. 1996).The primary threatderives rom thewholesale mechanized conversion of nativecerradoand campocommunitieso large-scaleagriculture,particularly soybeans. he dry-season racticeof annuallyburningopencoun-try habitats or small-scale griculture,deeplyingrained among most rural populations, s asecondaryhreatwhose ong ermenvironmen-tal consequencesave only recently raisedwidespread concern.Before the true conservation status of Suiririislerorum can be assessed, we first need a morecomplete nderstanding f its distribution.Weexpect hat t will eventually rove o be broad-ly sympatricwith S.s. affinishroughoutmuchof the cerrado egion.At present,Suiriri islero-rum is known to occur in two large nationalparks,ChapadadosGuimaraesNationalPark,Mato Grosso,Brazil, and Noel KempffMercadoNationalPark,depto.SantaCruz, Bolivia.Bothparks contain extensive areas of seeminglysuitablecerradohabitat,and shouldbe system-atically surveyed o assess ensitiesof Suiririislerorum and other cerrado endemics. Anotherprotectedarea that shouldbe surveyed or is-lerorums the ReservaEco16gica erra das Ar-aras in western Mato Grosso, Brazil.

The need for adequate surveys of endan-geredcerrado abitats asbeenpointedoutbyothers (Bateset al. 1992, Silva 1995, Parker andWillis 1997),but its importancecannotbe over-stated.Lack of understandingof speciesimitsin widespread, olytypicgroups,along with

incompleteknowlege of distributionsmay re-sult in the seriousunderestimation f regionaland local biodiversity and endemism.Suchmiscalculations ould have serious epercus-sionswhen important conservation rioritiesare beingset. n an analysis f the ntensityofcollectingefforts n the cerrado egion, Silva(1995)found that roughly70% of the cerradoregiondid not meet he criteriaof havingbeen"minimally sampled" or birds. t is instructivethat Suiriri islerorum occurs in at least seven ofthe sites hat met Silva's equirementsor beingsatisfactorally ampled, ncluding three re-gions (Goiania, Cuiab, and ParqueNacionalNoel KempffMercado)with a high densityofminimallysampledocalities, nd yet, hases-caped detectionby field workers. f a crypticspeciesof bird could be missed n the mostheavily sampled30% of the cerradoregion,then the potential or overlooked iodiversityin the remainingunder-sampled reasmustbegreat. Our recognitionof Suiriri islerorum s acrypticspecieswas nitially basedon an appre-ciation of vocal differences within Suiriri overa broadgeographicange. t is critical hat ieldpersonnel onducting urveysof the cerradoand other endangered abitatshave accessoadequate tape recording equipment and beproficient n the recognitionof bird voices,ormore taxa inevitably will be undersampledoroverlooked (Parker 1991).

ACKNOWLEDGMENTSWe are particularly grateful to Dionisio Pimentel(MPEG), who skillfully handled the collectingandspecimen-prepping uties on our collecting rip. T.Schulenbergwas a constant source of advice

throughout hisproject,and alsoprovidedassistancein obtaining somekey references. . Batesalso pro-vided much useful advice, and facilitated the iden-tification of plants from our study areas. Specialthanks must go to M. and E Isler, who generouslydonated heir time and talents o providing he mapand spectrogramsrespectively) sed n this paperK. Garrett (LACM) provided criticalassistancen co-ordinatingspecimenoans rom several nstitutions.We also thank J. V. Remsenand S. Cardiff (LSUMZ);T. Schulenberg, . Willard, and S. Hackett FMNH);R. K. Panza (CM); S. L. Olson and P. Angle (USNM);E C. Sibley YPM); C. Cicero (MVZ); and R. Ridgelyand D. Agro (ANSP) for the loan of specimensromtheir respective nstitutions.A. Schaffnerassistedwith the statistical nalysisof morphological ata.G.Budney,T. Bridgeford,A. Priori, and the restof thestaff at the Library of Natural Sounds,CornellUni-


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January 001] NewFlycatcher,fromerrado egion 77versity were of great help in allowing accesso theLNS collection f recordings. hanksalso o S.Hilty,R. Ridgely,and M. Cohn-Haft or sharingadditionalrecordingswith us. D. Lane painted the attractivecolorplate.B. Carlosprovided transportation n ourcollecting rip. We thank E. Goodale,D. Kroodsma,T. Schulenberg,nd an anonymouseviewer or theirhelpful commentson earlier drafts of this manu-script.Finally,we gratefullyacknowledge . Eman-uel for providing us with travel opportunities hathavemademuchof our work possible.

LITERATURE CITEDBATES,J. M., T. A. PARKER II, A. E CAPPARELLA, ND

T. J. DAVIS. 1992. Observationson the campo,cerrado and forest avifaunasof easternDpto.SantaCruz, Bolivia, ncluding21 species ew tothe country.Bulletin of the British Ornitholo-gists' Club 112:86-98.EITEN,G. 1972.The cerradovegetation f Brazil. Bo-tanical Review 38:201-341.

FARABAUGH,. M. 1982. The ecological nd socialsignificance f duetting. Pages85-124 in Acous-tic Communication in Birds (D. E. Kroodsmaand E. H. Miller, Eds.) vol. 2. Academic Press,New York.

HAYES, E. 2001.Geographicalariation, ybridiza-tion and the leapfrog pattern of evolution n theSuiriri Flycatcher Suiriri suiriri) complex ofSouthAmerica.Auk 118: n press.HELLMAYR,C. E. 1927. Catalogue of birds of theAmericas, part 5. Tyrannidae. Field Museum ofNatural History Zoological Series13.ISLER, . L. 1997.A sector-basedrnithological eo-graphic nformation ystem or the Neotropics.Pages345-354 in Studies n NeotropicalOrni-thologyHonoringTed Parker J. V. Remsen, r.,Ed.). OrnithologicalMonographs o. 48.ISLER,M. L., AND P. R. ISLER. 987. The Tanagers:Natural History, Distribution and Identification.Smithsonian Institution Press, Washington,D.C.

ISLER, M. L., P. R. ISLER, AND B. M. WHITNEY. 1997.Biogeography nd systematics f the Thamno-philus punctatus (Thamnophilidae) complex.Pages355-381 in Studies n Neotropical Orni-thology Honoring Ted Parker (J. V. Remsen,Jr.,Ed.). OrnithologicalMonographsno. 48.ISLER, M. L., P. R. ISLER, AND B. M. WHITNEY. 1998.Useof vocalizationso establish peciesimits nantbirds Passeriformes:hamnophilidae). uk115:577-590.ISLER, M. L., P. R. ISLER, AND B. M. WHITNEY. 1999.Species imits in antbirds (Passeriformes: ham-nophilidae): The Myrmotherulasurinamensiscomplex.Auk 116:83-96.KRABBE, ., AND T. S. SCHULENBERG.997. Specieslimits and naturalhistoryof Scytalopusapacu-

los (Rhinocryptidae),with descriptions f theEcuadorian axa, including three new species.Pages47-88 in Studies n NeotropicalOrnithol-ogy Honoring Ted Parker (J. V. Remsen,Jr.,Ed.).OrnithologicalMonographs o. 48.KROODSMA,. E. 1984.Songs f the Alder Flycatcher(Empidonaxlnorum) nd Willow FlycatcherEm-pidonax raillii) are innate.Auk 101:13-24.KROODSMA,. E. 1986.Designof songplaybackex-periments. Auk 103:640-642.KROODSMA,. E. 1989.Male EasternPhoebesSay-ornis phoebe, yrannidae, Passeriformes) ail toimitate songs.Journalof ComparativePsychol-ogy 103:227-232.KROODSMA, D. E., AND M. KONISHI. 1991. A subos-cine bird (EasternPhoebe,Sayornishoebe) e-velopsnormal songwithout auditory eedback.Animal Behaviour 42:477-487.

LANYON,W. E. 1978.Revisionof the Myiarchusly-catchers. Bulletin of the American Museum ofNatural History 161:429-627.MARR,T. G. 1981.Breedingand foragingecologyofthe Cactus Wren in a variable environment.Ph.D.dissertation, ew MexicoStateUniversity,Las Cruces.

MCKITRICK,M. C., AND R. M. ZINK. 1988. Speciesconceptsn ornithology.Condor90:1-14.MEYER ESCHAUENSEE,. 1966.The Species f Birdsof South America. Livingston, Wynnewood,Pennsylvania.PARKER,. A. III. 1991.On the use of tape recordersin avifaunalsurveys.Auk 108:443-444.PARKER, t. A. III, AND E. O. WILLIS. 1997. Notes onthree tiny grassland lycatchers, ith commentson the disappearance f SouthAmerican ire-di-versifiedsavannas. ages549-555 in Studies nNeotropicalOrnithology Honoring Ted Parker(J. V. Remsen,Jr., Ed.). OrnithologicalMono-graphsno. 48.PAYNTER,R. A., JR., AND M. A. TRAYLOR, R. 1991.OrnithologicalGazetteer of Brazil. Museum ofComparative Zoology, Cambridge, Massachu-setts.

RIDGELY, R. S., AND G. TUDOR. 1994. The Birds ofSouthAmerica,vol. 2. Universityof TexasPress,Austin.

SHORT, . L. 1975. A zoogeographic nalysisof theSouth American Chaco avifauna. Bulletin of theAmericanMuseumof Natural History 154:163-352.

SIBLEY,C. G., AND B. L. MONROE, JR. 1990. Distri-bution and Taxonomy f Birds of the World. YaleUniversity Press,New Haven, Connecticut.SICK,H. 1993. Birds in Brazil: A Natural History.Princeton University Press, Princeton, NewJersey.SILVA, . M. C. 1995.Avian inventory of the cerradoregion,SouthAmerica: mplicationsor biolog-


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SMITHE, F. B. 1975. Naturalist's Color Guide. Ameri-can Museum of Natural History, New York.STOTZ,D. F., J. w. FITZPATRICK,. A. PARKERII, ANDD. K. MOSKOVITS.996.NeotropicalBirds:Ecol-ogy and Conservation. niversityof ChicagoPress,Chicago.TRAYLOR, . A., JR.1979.Tyrannidae.Pages1-229 inChecklist of the Birds of the World, vol. 8 (M. A.Traylor, Jr., Ed.). Museum of ComparativeZo-ology,Cambridge,Massachusetts.TRAYLOR, . A., JR.1982.Noteson tyrant flycatchers(Aves:Tyrannidae).FieldianaZoology 13:1-22.

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Documents

A Cryptic New Species of Flycatcher (Tyrannidae Suiriri)