the Bearded Tachuri Polystictus pectoralis

Transcription

the Bearded Tachuri Polystictus pectoralis
Eird Cons€rvation Intematio al l1q5) 5:367-)p
The distribution and conservation status of
pectoralis
the BeardedTachuriPolystictus
N. I. COLLAR andD. C. WEGE
Summary
The Bearded Tachuri Polysfirtuspectoralisoccupieslowland grassLandswith scrubby
vetetation,generallynear water, in the Andeangrasslandsof Colombiaat two sites
(threatenedrccebogotensis),
savannasin eastemColombiaand the lowland and tepui
grasslandsof mainly southem Venezuela,Guyana, Surinam, French Guiana and
reappearingsouthof the Amazonin cenhal-southem
northemBrazil(tacebrmipennis),
Brazil, eastem Bolivia (no recent records),Paratuay, Uruguay and northem and
It is an australsummervisitor (October/
Argentina(nominatepecforalis).
central-eastem
Argentina,nesting(commonlyin thistles)
Novemberto February/April)to central-east
sallying,
around December,clutch-sizethree. It feedson insectsby perch-gleaning,
hover-gleaning
and still-hunting.It is unobtrusiveand must be commonlyoverlooked,
Overall,however,it is scarce
andin somelocalitiesmaybe moderatelywell represented.
grasslandhabitatswithin its rangehave
and appearsto be very patchyin occurrence;
beenconvertedwholesaleto farming, New quantitativecriteriasuPPortearlierqualitative
iudtement that the speciesis probably not (yet) threatened,but that it merits
may be Sood
status.Su88estions
that one or all of its threesubsPecies
near-threatened
speciesare premature;it is not evenclearhow distincttheseformsate as subsPecies.
Introduction
Habitats in South America other than tropical forests and wetlands have only
relatively recently become a subiect of serious concem in conservation. In
particular, the natural grasslandsof the continent have been badly neglected
while attention has been focused on biologically richer habitats, with the result
that vast areas of open country have been allowed and indeed encouraged to
be converted to human food production with barely any recognition of their
biological value.
Thesegrasslandshost a number of biome endemics, sometimeswide-ranging
so that large areasof habitat are needed for their preservation (e.g. maned wolf
dichotoffius).Ornithologically,
Chrysocyonbrachyurusand marsh deer Blastocerus
a broad suite of species depends to some extent on Neotropical grasslands.
As many as 38 of them were recently listed as threatened (Collar et al. 7gg2),
representing tz%oof all threatened New World species(Collar ef al. in press).
In addition, several species were listed as "near-threatened", notably those
whose centre of occurrencelies in the grasslandsof interior south-eastBrazil,
Paraguay,Argentina and in some caseseasternBolivia, for example Cock-tailed
Tytant Alectrurus tricolor, Sharp-tailed Grass-t1'rant Culicitsora caudacuta and.
melanotis(see, e.g., Collar et aI. ry9z.795).
Black-maskedFinch Coryphaspiza
N.l. Collarand D. C. Wege
J68
Concern expressedover the plight of the BeardedTach.uriPolystictuspectoralis,
"a tiny, buffy flycatcher found very locally in tall grass areas [which] may well
deserve threatened status" (Ridgely and Tudor 1994), caused its listing in a
preliminary treatment of globally threatened birds (Collar and Andrew 1988).
Ted Parker strongly shared that concern and, as a co-author of the fuller
evaluation of New World species(Collar et al. 992), he prepared some notes
to support its continued listing. We duly assembled the evidence, through a
review of all published sources, accumulation of data from specimens in as
many museums as possible(seeAppendix), and extensivecorrespondencewith
fieldworkers familiar with the speciesand its habitat (recently supplemented by
an appeal for records made in Colingar: 48). We concluded that its status was
not yet so severeas to warrant retention of threatened status, treating it instead
as near-threatened(Collar et al. ry92), a judgement which held when all New
World specieswere recently re-evaluatedagainstnew criteria (Collar et al. ry9$.
However, as with many other near-threatenedspecies, we were left with an
extensivebody of material on the bird, much of it unPublished and all of it, if
arrangedproperly, capableof providing a baselinedatasetfor current and future
evaluation and monitoring of its status. In homage to Ted Parker, whose voice
was amongst the first and loudest to be raised in alarm at the plight of South
American grasslands,we offer this dataset here.
Museum initials used in the following account are Siyen in the Appendix,
and an explanation of the use of the asterisk(*) appearsin the legendsto Figures
z and 3.
Distribution
The Bearded Tachuri has a disiunct distribution in South American grasslands
either side of the Amazon basin. To the north it has been found in one or two
highland areas of western Colombia (race bogotensis),and in the lowland
savannas of eastem Colombia eastwards through central Venezuela into the
tepui region of southem Venezuela,Guyana, and northern Brazil, with isolated
populations in southern Surinam and northern French Guiana (racebrnipennis).
South of the Amazon it reappears in the nominate form, ranging through
southem Brazil, eastern Bolivia, Paraguay, Uruguay and the northem half of
lowland Argentina. The records that allow us to compose this generalized
assessment(see Figure 1) are set out below, arranged in sequenceswithin and
by the maior subnational political divisions (states, departments, provinces;
except for the Guianas) from west to east and/or north to south, with numbers
in Figures z and 3 corresponding to superscript numbers in the text.
Polystict us pectorulisbogotensis
Colombia (Cundimmarca) This form is known with certainty only from Suba
marshes', z,7tt m, in what are now the northern suburbs of Bogotri (Cory and
Hellmayr ry27, Paynter and Traylor r98r). Hilty and Brown (1986)say "once"
from this site, but this cannot be correct since the type-specimenwas collected
Distributiot anil statusof thc Baflld Tacturi
Figurer. Thedistnbutionof theBearded
Tactrurithroughoutits range,basedon records
agsembled
in the text.
in April r9r5 (Chapman r9r5) and there ie a specimendated January r9r7 in
AMNH and another from April r9r9 in USNM, plus a specirnensimply labelled
Bogot6,taken on r9 Mardr of an unspecifiedyear, in MCZ; moreover,there are
apparently two specimensin Museo de la Salle,Bogot6,dating from the r95oo
N. J. Collarand D. C. Wege
37o
(F. G. Stiles in litt- r,994).(alle) A specimen from Pavas'?,La Cumbre, above
Dagua at 1,150m on westem slope of the West Andes, taken in July r9r8, was
(Cory and Hellmayr r9z7; specimen in
assumed to belong to the race bogotensis
CM) and has subsequentlyentered the literature as such (Hilty and Brown 1986,
Fjeldsi and Krabbe r99o, Ridgely and Tudor 1994;but see Taxonomy below).
Polystictuspectoralisbretipennis
Colombia(Meta) Only two areas are so far documented, in the north-west and
north-east (Hilty and Brown 1986):r5 km south of Puerto L6pez3, December
r97r (specimenin ANSP), and (clearly the same or adjacent locality) at Laguna
Mozambique, r4 km south and 10 km east of Puerto L6pez, February 1.970(two
specimensin ANSP), with one seen there in fanuary 1993 (F. G. Stiles fu liti.
1994);and Carimaguar, r5o m, May and June ry76 (four specimensin FMNH,
IND), where birds were present in small numbers in November 1993 (F. G.
Stiles fu lltt. 1994).
The speciesis expected to occur in adjacent Vichada and also Arauca (Hilty
and Brown 1986).
Venezuela(Carabobo)
El Paito, near Valencia' (museum specimen of unknown
date reported by C. Parrish in litf. 1986to R. S. Ridgely; also Ridgely and Tudor
t994); (Barinas)Santa Biirbara6and Ciudad Bolivia?(Phelps and Phelps 1963);
(Apare) Guasdualito" and Palmarito' (Phelps and Phelps 1963);(Amazonas)El
Platanal'o (Phelps and Phelps 1963); (Boliz'ar) Quiribana de Caicararr
(type-locality), Rio Orinoco, April 1898 (von Berlepsch and Hartert 1902);
Maripar'?,Rio Caura, October and December r9o9 (two specimensin CM; also
Cory and Hellnayr 927), a locality now known to visiting birdwatchers, with
3-4 being seen there in late February 1994(B. E. Wright in litt. ag94\;km zoo
on El Dorado-Santa Elena road, Canaimar3National Park, February r99r (R.
Hopf in litt. 1994);Urimiin'i (Phelps and Phelps 1963);Acopiin-tepuils (Phelps
and Phelps 1963);Kanavaydn'" (Kabanaydn)(Phelps and Phelps 1963),whence
also a record in the early r98os (M. L. Goodwin in litt. r99z); Santa Elena de
Uair6n'7,96o m, January r95o (specimenin COP; also Phelps and Phelps 1963);
female-plumaged bird, *Quebrada Pacheco'",km 236 on road to Santa Elena
through the Gran Sabana,April 1994 (M. Kessler in litt. t99$;4 km west of
*Peraitepuileon the road from San Franciscode Yuruanu to Peraitepui,
9oo m,
in the Gran Sabana, April ry94 (M. Kessler in litt. t9g4); Cerro Roraima'?o,
November and December r88r, June, October, November and December 1883,
and October 1898 (r2 specimens in ANSP, BMNH, USNM, at least three of
which were collected at 1,060m; also Salvin 1885, Sclater 1888, Phelps and
Phelps 1963), including Paulo, October and November t9z7 (Chapman r93t;
three specimensin AMNH).
Gayana(Roraimaspecimensare treated as stemming from the Venezuelansector
above: see Stephens and Traylor 1985.)Upper Takutu Mountains2', r9ro8(two
specimensin AMNH, BMNH; also Chubb rgzr); Annaiz, May and June r89o,
February 1891and June r89z (seven specimens in AMNH, ANSP); two miles
Distributionand statusof the BeardedTachuri
37r
Figurez. The distributionof the BeardedTachuri,subspecies
bogotensis
a\d brcaipennk,
Numbersby localitypointscorrespondto thosein the text underDstribution.Coordinatesfor theselocalitiesarederivedfrom Paynter(1982),PaynterandTraylor(r98!, r985,
r99r), Stephensand Traytor(1985),or elseTie Timesatldsof theworw(seventhedition).
Localitiesnot in thesesourcesare markedin the text with an asterisk(') and are as
follows, with sourcesfor their coordinatesas shown: QuebradaPacheco,c.5'o8'N
61'o6'W(M. Kessls in litt. t994\;Peraitepui,c.5'ol'N 6o'56'W(M. Kesslerin litt. aggdeast of Lindena Highway about 15 miles south of that highway's northern
terminus, August 1993(R. Ryan in litt. 1994).
Surinam Sipaliwini'z{,male taken lanuary 1966(Mees 1968) with an apparent
female in May ry72 (Haverschmidt and Mees 1994;specimensin RMNH).
FrenchCuinna Sinnamarys, November 1986and March 1989 (three specimens
in CMN). Neither of these records was known to Tostain et al. (:992), who
however mentioned records from this locality (qualifying it as "la savane des
PEres") in December 1987and a few months later, plus another in the savane
de Cournbi-Sinnamaryin July r99r.
Brazil (Roraima)Fazenda Santa Cecilia, opposite Boa Vista26on the east side of
the Rio Branco,February and March r99z (D. F. Stotz in litt. 1995);Rio Mucajaf?,
south of Boa Vista, Apil 196z(specimenin MZUSP; also Pinto 1966)and March
1963(specimen in MPEG; also Novaes ry67); @ard)Cabaceirasdo rio Paru de
Oeste, PostoTiri6sa 34o m, June 196o(at least three specimensin MNRJ, MPEG;
also Novaes ry67\; (Anapd) Acampamento no. 4, igarap6 Ariramba, right-bank
affluent of Rio Tartarugal", July 1969(two specimens in MPEG; also Novaes
1978).
Polystictuspectoralispectoralis
Brazil (Goitis)Aragargass,June 1953(specimen in MNRI; locality also specified
by Sick 1993);Goidniarl, September 1967(specimen in MPEG); Emas National
N. I. Collarand D. C. Wege
j72
Park32,;gSo-:'ggz, including the months of September and October (R. S.
Ridgely, T. A. Parker in liff. r99z; also R. Schofieldin /iif. 1994),and just outside,
August 1989(R. Schofield in litt. r9g; (Mnto Grosso)Chapada dos Guimar6es33
("Chapada"), Autust 1882(two specimensin AMNH), July and Septemberr883
(specimens in AMNH and MNR| respectively) and May to September 1885
(seven specimens in AMNH, BMNH, MCZ; also Allen r89z); Cuiabiis, July
presumably of r8z4 (specimen in BMNH; von Pelzeln t868-r87r, Sclater 1888)
and again in September ryg3 by the airport (A. Whittaker in litt. t994); porto
Jofie35,Transpantaneira, August 1988 (R. Fairbank and N. Preston per B. C.
Forrester in litt. tg9g, and north of Porto Jofre, August r99r (T. A. parker in
litt. rggz); (Mato Grossodo Sal) *Passodo Lontra*, August r99r (J. F. Pacheco
verbally r99z to L. P. Gonzaga);Campo Grande37,J,tly r93o (seven specrmens
in MCZ, MZUSP), and the nearby Fazenda Curralinho, September 1938
(specinen in MZUSP; also Pinto 1944),with severalsingletons south of Campo
Grande, June 1983 (R. S. Ridgely in litt. r9g); near *PixaimT along the
Transpantaneiraroad, Pantanal,in September1992(K. Zimmer and T. A. parker
per A. Whittaker in litt. 1994);(SdoPaulo. Calg6o do Couro.,, April r8z3 (von
Pelzeln 1868-187r),now within a suburb of Ituverava (Cotlar el al. ry92:759);
EstagaoEcol6gicaEstadual de Itirapina, near Itirapinae, 76o rn, lanuary r99z
(Willis r99:) and December 1993(R. S. Ridgely, D. K. Dacol in litt. t994); and
at least one other locality in the past zo years (E. O. Willis in litt. t 986);(Rio
Grandedo Sal) Itaquint, Novernber r9r4 (specimen in MZUSp; also pinto 1944);
Porto Alegrea'?,
unknown date (Gliesch r93o).
Boliaia(SantaCrlz) Buena Vista'3, "Prov. Sara", fuly rgrz (Cory and Hellmayr
rgzT); Santa Cruz{ ("Santa Cruz de la Sierra"), August and September r9o9
(Cory and Hellmayr r9z7 six specimensin CM and in YPM); ,,Cirnpa,
7oo rn,
Prov. Sara" (i.e. Provincia Guti€rrezr5),October r9o8 (specimenin AMNH; also
Zimmer 1955);probably also Santa Anas ("Santa Ana, Chiquitos,,), which is
the type-locality of Muscicapastramineouentris
Lafresnayeand d,Orbigny rg37,
the type material for which is apparently lost but whose description s'trongly
suggeststhe immature plumage of and hence synonymy with p. p. pector;Iis
(Hellmayr tgz.5; also Cory and Hellmayr r9z7).
Paraguay(Boquerdn)Orloff!7 (Colonia Mennonita), October 1945 (specimen in
FMNH); (Presiden
te Hayes)2j5 km west of *Riacho Negros, July and August
r.939(hve specimensin UMMZ); Latuna Escalanteae,
August 196o(Steinbaiher
196z);Villa MilitaP, July 1945 (FMNH); Lichtenau5l, February (year unclear),
August and October t97t (Short 19Z6; three specimens in AMNH); Laguna
General Diazs'?,July ;945 (FMNH); zo km east of pozo Colorado5.,September
1989 (two specimens in MHNG); Makthlawaiya!, March r93r (specimen in
AMNH; also Zimmer ry55); Puerto Pinasco55,Rio paraguay, September and
October 1916(two specimensin AMNH; also Zimmer r95j) and Septemberrgzo
(two specimens in USNM; also Cory and Hellmayr r9z7); Benjamin Acevals,
undated (Bertoni 1930); west bank of Rfo Paraguay, across the river from
Concepci6n57,May 1989 (F. E. Hayes in litt. 1,994);(Concepci6n\Estancta
Centuri6n$, May ry89 (F. E. Hayes in litt. r94); San Luis de ia Sierra' 1,,La
Fonciere"), May ry3r (Zimmer 1955;four specimens in AMNH); Bel6n@,RJo
Dist/ibutionand statusof the BeardedTachuri
)7j
Ypan€, August 1930 (Zimmer 1955;specimen in AMNH); Horquetau', fuly to
October 1935 (specimens in ROM, UMMZ); (AmambaylCerro Amambayu'?,
September ry38 (UMMZ); (Canindeyfi Lagunita, Reserva Natural del Bosque
Mbaracayf6', September r99z (Brooks et al. q93); (Alto Paran\ open areas of
*ReservaTati
Jupf', just north of Ciudad del Este, a few times in the r98os (N.
Perezin litt.1988 to L. P. Gonzaga);(Guaird)Yillaricad, July r9z4 and July r9z5
(two specimensin BMNH); (Cenfral)Nueva Italia*, July and August r94o (three
specimens in AMNH); *Bemal-cud67,near Asunci6n (undated but probably
nineteenth century specimen in ZSM; site mentioned by Cory and Hellmayr
1927but untraced by Paynter ry89); (Paraguari)Sapucai*, March r9o4 (Chubb
rgro); Escobaf, May and June r9o8 (two specimensin MACN); Paraguari^, in
the period late June to mid-August 1893(Salvadori $95); (Misiones)zo km west
of San Juan BautistaTl,August 1994(F. E. Hayes in litt. t994);5 km north-west
of Santiago", March 1989(F. E. Hayes and j. L. Ramirez in litt. 1,99D.
Uruguay (Artigas) San GregorioT3(Cuello and Gerzenstein ry62\; (Tacuaremb6)
Pozo HondoTa,April 1958 (specimen in MNHNM; refened to by Cuello and
Gerzenstein ry62); (Paysand\ PaysandriT5,
November 1883(specimenin BMNH;
also Gibson 1885,Sclater$88\; (Soriano)Santa Elena76,Rio Monzon, November
r89z (two specimens in BMNH; see Aplin $94); (Montnideo) Montevideot,
austral summer r83r-r832 (Gould r84r).
Argentina (FormosalComandante FontanaTs,September 1929 (specimen in
AMNH); ClorindaD, San fos6, October r9z5 (specimen in ZSM); *Espinilloe, in
the north-eastof the province, July 1988(8. M. L6pez Lanus in litt. 199r);(Chaco)
Las Palmas3r,Rio Quia, July rgzo (specimen in USNM; see Wetmore 19z6);
*Irarana32,March possibly of 186o(specimen in USNM; see Remark z in Collar
et al. t99z:79); (Misiones)Arroyo Urugua-ie, km ro, April r95z (a young male
in a clearing in the San Martin mat€ plantation near Puerto Bemberg)(Partridge
t954\, Apnl 1958 (Navas and 86 1988, who mention three specimens, with a
further seven in AMNH), July and August 1958(five specimensin AMNH) and
June 196r (specimen in YPM); (Corrientesl Santa Ana&, January ry87
(Environmental Investigation Agency in Pearman and Abadie 1995);Estancia
San Joaquins, San Carlos, Rio Aguapey, July 196r (two specimensin AMNH,
LSUMZ); present in 1989 in the area of the new Mburucuy6e National Park
(M. A. E. Rumboll per J.-C. Chebez in litt. t99z); Laguna Iberii87,April r99o
(8. M. L6pez Lanus in litt. 1991); Estancia Rinc6n del Ombri*, Mercedes,
October 196r (specimen in AMNH); (Entre Riosl Arroyo Bani"', January 1993
(M. Nores in litt- 199 1*Ruta Nacional rz{, 9 km south of the junction with
Ruta Provincial 5, February 1993 (female with two dependent immatures:
Pearman and Abadie 1995); Pronunciamentoer,Decernber r97o (nesting pair
with young: T. Narosky in Pearmanand Abadie ryg); la Soledadq, December
1898,October 19or, February rgoz (Hartert and Venturi r9o9; three specimensin
AMNH); Gualeguaychrie3,
December 1959(Camperi r99z); outside *Larroqueq,
February 1993 (one immature netted: Pearman and Abadie t95l; (Santa Fe)
EstanciaEl Orden, Tostado's,October 1938(specimen in MACN); EstanciaLa
Germania%,Las Rosas,luly rgz5 (specimenin ZSM); (Cdrdoba)
Bafladosdel Rio
Dulce" (Nores and Yzurieta r98o, Nores et aL ry83); south coast (Altos de
N. l. Collarand D. C. Wege
)74
Chipi6n and Desembocaduradel Rio Segundo) of Mar Chiquitas (Nores and
Yzurieta r98o, Nores et al. 1983,M. Nores and D. Yzurieta in litt. t986); near
C6rdoba', 1829 (specimen in BMNH; also Cabanis 1878,Sclater 1879, Sclater
1888,Sclaterand Hudson 1888);Embalset@
(de Rio Tercero),where nesting has
been recorded (Nores and Yzurieta 1980,Nores et al. ry83, M. Nores and D.
Yzuriela in litt. a986), this presumably being the source of the record from the
district of Calamuchita (Canevari et al. a991.);Leonesrol,January 1949,October
r95o, January 196r (five specimensin MACN) and February 1989(Pearmanand
Abadie 1995);Sierrade Comechingonesro2
at r,6oo m, on the road to Atos Pampa
(Nores and Yzurieta 1980,Nores ei al. 1983),this possibly being the area called
the Sierra de C6rdoba by Cabanis (1878);(Bunos Aires) (records here are based
chiefly on the maps - including that showing the partidos, or districts - in
Narosky and di Giacomo 1993)San Antonio de Arecoro3;Escobar,presumably
at Zelaya'- (Pereyra 1923, 1938;also three specimens in MACN dated April
1922,October 1945and - a juvenile - january 1946),with the speciesnow listed
for the Otamendi National Scientific Reserve (see Chebez ef al. in press);
*Benavidezlo5,west of Tigre (8. M. L6pez Lanus ln litt. tggr); Pilar'6; Capital
FederalroT,
i.e. Buenos Aires (a female seen in November r99ro:M. Babarskasin
litt. 1ggzr,in two casesspecifying Costanera del Sur, in October 1985 (B. M.
L6pez Lanus in litt. tggr) and in November r99z (R. Schofieldand H. W. Wallis
in litt. r99$; *Estancia Santa Elena (see note below)rff, November 1892 (two
specimensin BMNH; Holland 1893);General Pintorm;Ensef,ada(Punta Lararro:
Klimaitis and Moschione ry8); La Plata (La Platarrrtown, February r9r9 and
November 1,946l.two specimens in UNP and MACN respechvely); Berisso"'?
(nesting recorded at a date between 1967 and.t97o: M. Nores and D. Yzurieta
in litt. 1986\;Saladillo'r3(two nests in December1985:B. M. LfpezLanus in litt.
r99r); Las Rosasrra,November r9r7 (Daguerre rgzz; specimen in MACN); Las
Floresrr5;Bolivarttu (August 1947: specimen in MACN); General Pueyrred6n
(presumably at Chapadmalal"T:see Martelli 1989);Saavedra(i.e. serranfasde
Curam6lan, Pigii6r'", November 1988:Narosky et al. r99r); Tomquist""; Bahia
Blancar2o,November 1899 and October rgroo(Hartert and Venturi t9o9; two
specimens in AMNH), and November rgro (specimen in ZSM); (I-a Pampa)
General Picor2r,December 1935 (specimen in MACN; hence the listing of the
province in SOMA rg35-rg4z); (Mendoza)Potrerillosrz, r,5oo m, March rgzr
(Peters 1923; specimen - a juvenile - in MCZ); (Santiagodel Estero\listed by
SOMA (1935-1942),hence doubtless in Olrog (1979) and,Ridgely and Tudor
(1994), but not mentioned by Nores et al. (1.Wr), although M. Nores ifl litt.
(1995)suspectsit may yet be found in the extreme south-easton land formerly
within C6rdoba Drovince.
The positionof EstanciaSanta ElenaPaynter (1985)cited addressesin lbis to
indicate that this locality is not in Entre Rios, as has repeatedly been assumed.
These addressesvariously mention an estancia called Media Luna "4o miles
south of Soler", and "Estancia Sta. Elena, Halsey", etc., on the Pacific railway.
In a map (Lopez 1898) Soler appears on the railway line to San Luis and
Mendoza in the middle of the section that traversessouthernmost Santa Fe, so
that "4o rniles south" lies inside Buenos Aires province, where indeed there is
a farm named Media Luna iust north of a station called Halsey on another
railway running west from Buenos Aires city to the iunction of the borders of
Distributionand statusof the BeardedTachuri
)75
C6rdoba and La Pampa. Comparison with Tle Timesatlasof the world suggests
that Halsey is now Ameghino and the position of Media Luna, which must
either have been a synonym or neighbour of EstanciaSanta Elena, should lie
close to the present-day Santa Eleonora at 34"9'3 62"4o'W.
Habitat
The habitat of the Bearded Tachuri has been described in numerous ways, all
qualitative in nature and (other than in the synthesizingliterature) local in focus.
The elevationsare varied but, apart from the Suba marshes rccord of bogotensis
(2,7n m) and two records from the Andean foothills in western Argentina
(r,6oo m and 1,5oom), all are frorn below r,35o m (the altitude of the other
bogotensis
record and the upper limit for tepui localities),with the lowest stated
elevation being r5o m.
From Meta, Colombia, there are two accounts of the habitat. According to
one, the species is found in open savanna with scattered bushes and tall
clumped grass(,4ndropogon
sp.) and.weeds (S. Fumiss in Hilty and Brown 1986).
In the other, birds have been seenin grassy drainage ditches and on the grassy
fringes of ponds (F. G. Stiles irr litt. t99$.
For Venezuela the only published account refers to "swampy placesin low,
open woodland, forest edge, savahnasto 2oo m north of the Orinoco, to 1,loo m
on the slopesof the tepuis" (Meyer de Schauenseeand Phelps 1978).However,
in the Gran Sabanathe speciesis "found primarily in well-drained tall grassland
with abundant shrubby growth, usually within a few hundred metres of forest",
with birds "apparently rare or absent from more open grasslands that are
frequently burnt" (T. A. Parker in litt. tg92). Nevertheless, near Peraitepui in
Apnl 1994the habitat was recently bumt open savanna on poor, sandy soil,
with most vegetation only c.zo cm high, although the birds were in or near a
group of ro or so small bushes c.7o cm high, while at Quebrada Pachecothe
single bird observed was in a small (3oom'z)patch of dense grassy vegetation
between a river, a road and sorneriverine forest, this time with grassesc.5o cm
and bushes c.7o cm (M. Kessler in litt. rgg4l. At both sites the vegetation was
composed primarily of Mynchosporaand. Paepalanthus
with scattered bushes,
and, since the specieswas not found during several weeks spent in one area
of grassy savanna from which bushes were absent, it was speculatedthat the
Bearded Tachuri requires scattered bushes within open grassy savannas (M.
Kessler ir litt. 1.994.
In French Guiana the habitat is "high grasson wet soils in savannas" (Tostain
et al. 1.992),while in Surinam the specieshas been found in "tussock grassland
and low scrub" (Haverschmidt and Mees 1994); G. F. Mees (verbally 1995)
commented that he expectedto find it in grassy areaswhere bushier vegetation
grew on damper (seasonallywet) ground, but he did not encounter it in the
Rupununi savanna of southern Guyana, which was much wetter and perhaps
more damaged by cattle.
In Brazil breoipennisoccurs in the campos (open savannas) north of the
Amazon, and in the campo-cerrado(grassland/savanna)region to the south.
Specimenlabel data refer to "campo lavrado" (a local term for ploughed land)
in Roraima (MPEG) and "capim laraguit" (a speciesof grass Hyparrheniarufa
N. I. Collarand D. C. Wege
376
Figure 3. The distribution of the Bearded Tachuri, subsPecies pectoralis. Numbers by
locality points correspond to those in the text under Dstribution. Coordinates for these
localities are derived from Paynter (1985, 1989,a9gz, 1994),Pa)'nter and Traylor (191),
or else Tfie Times atlas ol the worw (seventh edition). Localities not in these soulces are
marked in the text with an asterisk (*) and are as follows, with sources for their coordinates as shown: Pixaim, 16'45'5 S6"SZ'\N(Office of Geography 1963);Passodo Lontra,
very roughly t9"4o'S 57"2o'W Oased on information from L. P. Gonzaga in litt. 1'995)t
Riacho Negro, 23"24'5 5fzo'W (Office of Geography 1957);ReservaTad Jupi, z5'3o'9
54'3o'W (read from IUCN r99z); Bemal-cui, assumed to be in Central since known to
be near Asunci6n (Paynter 1989), hence placed at z5't6'S 57'4o'W; Espinillo, z4'58'S
58'34'W (Office of Geography 1968);Ruta Nacional 12 at 32"18'S59'o9'W (Pearmanand
Abadie 1995);Larroque, 33"o2'S 58"59'W (Pearman and Abadie t995); Benavidez, 34"25'9
58'p'W (M. Pearmanin litt. tggi'; EstanciaSanta Elena, 34'43'3 62"4o'W(seetext).
Distributionand statusof the BeardedTachuri
377
introduced from Africa) at Campo Grande (MZUSP). In Roraima in early r99z
(in ihe middle of the dry season)birds were present in a small, lowJying area
of seasonallyflooded, tall (up to 60 cm), dense bunchgrass, close to a stream
but with no bushes; no birds were found in adjacent very dry, heavily grazed
campo grasslands(D. F. Stotz in litt. 1995).At Cuiabe in 1993a bird was seen
in wasteland adjacent to the airport approach road, near seasonallythen very
dry grasslandand scrub (A. Whittaker in litt. 1999. In Emas National Park the
species seems to be confined to tall grass and dense shrubbery along small
streamsthrough open grassland (T. A. Parker in litt. r99z). An individual seen
in the Pantanalin western Mato Grossowas foraging in the tops of small bushes
and in clumps of tall grass at the edge of a marsh (T. A. Parker in litt. t 99z).
At Itirapina birds are most numerous and breed in upland "campo sujo" (i.e.
shrubby grassland)habitat, although single birds passthrough disturbed, bushy
pastures, especiallyin winter (E. O. Willis perT. A. Parker in litt. 1992).
In the chacoregion Wetmore (1926)found the species"among weeds and low
bushesin pasturesnot far distant from water", and Short (r975) characterizedits
habitat as open bushy country, including savannas,pampas, woodland edges
and scrub desert, especiallynear water, including pantanal and the more open
parts of chaco woodland. In Uruguay Aplin (1894)found his two specimensin
"a belt of young plantation with undergrowth of grass,thistle, and other plants,
joining the barley chacra".
ln Argentina the species inhabits grasslands, secondary (i.e. weedy)
herbaceous vegetation ("yuyales") and arid savannas with tall, hard grass
("pajonales")in the vicinity of lakes, marshes with reedbeds ("esteros") and
flooded areas ("baiiados")(Nores and Yzurieta r98o, Narosky and di Giacomo
1993),but also in fairly modified agricultural areas (even for nesting), which
suggeststhat habitat alteration is not the main cause of its scarcity (M. Nores
and D. Yzurieta in litt. t986).Indeed, Partridge's (1954)specimen from r95z in
Arroyo Urugua-i was from an open area inside a mate plantation, while
Pearmanand Abadie (1995)have noted that in the north-east of the country the
speciesseems to have colonized the borders of roads and railways, although
M. Pearmanacceptsthat its absencefrom many areasis a causefor concem: in
general his records are from tall grassesand thistles Cynaracardunculusin areas
of dry soil, but often adiacent to humid areas.
Two recent synthesesof all this information have been: "reed and rush-beds,
and neighbouring grassland, thistles, bushes and trees" (FjeldsAand Krabbe
r99o), and "savannas, tall grass in cerrado, Lightly grazed fields, and adjacent
shrubbery" (Ridgely and Tudor 1994).Both are clearly appropriate (the use of
reedsand rushes is presumably inferred from the species'soccurrencein habitat
adjacent to "estercs"),but neither claims to identify the essenceof Bearded
Tachuri habitat. What seemsto emerge from the notes and impressionsamassed
above is what Ted Parker wrote in his notes on the species, that Bearded
Tachuris "inhabit a variety of types of grassland, all with ztaryingaflounts ot'
shrub\ regetation"(our italics), a judgement that clearly mirrors the view of M.
Kessler based on his experience in the Gran Sabana.However, D. F. Stotz's
r99z records from Roraima fail to fit this pattern, and R. S. Ridgely (in litt. 1gg5)
has also questioned it. The other important factor appears to be water, the
presenceor proximity of which is repeatedly indicated by observers.This may,
N. I. Collarand D. C. Wege
378
perhaps, simply be the factor that promotes different levels and types of
vegetation in otherwise uninterrupted - and hence perhaps for the tachuri
uninhabitable - grassland: Kessler's account of the Gran Sabana stressesits
aridity, and R. S. Ridgely (in litt. tg9) has found the speciesfar from water in
both Emas and ltirapina. All the same, wet areas seem too recurrent a
characteristicof Bearded Tachuri habitat (even if only when adjacent) to be
discarded as of no significanceto the species.
Feeding, breeding and seasonality
When foraging, the Bearded Tachuri will cling to grass stalks and perch-glean
nearby surfaces (T. A. Parker in litt. r99z), but to describe it as a "strict
perch-gleaner" (FjeldsAand Krabbe r99o) is mistaken. Birds make short sallies
within grass to pick off insects, frequently changing perches but rarely flying
far (Ridgely and Tudor ry94), and they regularly hover briefly to glean small
insects from blades of grass and leaves of small bushes (T. A. Parker irl litf.
tggz, D. F. Stotz in litt. 1995).The Cuiabd airport bird was still-hunting, sallying
to the ground from a perch 3 m up in a bush (A. Whittaker in litt. r9g4\. Abird
near Leones, C6rdoba, was likewise perch-hunting small caterpillars from the
ground in an overgrown allotment, flying up to a low barbed-wire fence to eat
them (M. Pearmanverbally 1995).Stomachsof three birds collectedin Roraima,
early rg9z, contained insect parts (D. F. Stotz in litt. 199 .
The assertion that the speciesis usually in pairs (Holland 1893,FjeldsAand
Krabbe r99o) is contradicted by Ridgely and Tudor (1994), who report it as
"usually seen singly, less often in pairs", but who add (see also R. S. Ridgely
in Hilty and Brown 1986) that birds sometimes accompany flocks of other
grasslandbirds such as grass-wrensCistothorus,seedeatersSporophila
(especially
Plumbeous SeedeaterS. plumbeal,Black-maskedFinches Coryphaspiza
melanotis
and Sharp-tailed Crass-tyrants Culicivora caudacutaianother observer adds
grassquitsand spinetails (R. Schofield in litt. t999. T. A. Parker (in litt. t99z)
found them usually in pairs or in small family groups of three or four, and
also noted their regular associationwith seedeatersand other small grassland
insectivores.
The natural history notes provided from Argentina by Holland (1893)appear
to have been neglectedfor over a century, but are worth reproducing for their
insights on breeding activity: "These birds inhabit the quinta, and are of a very
restlessdisposition before nesting, constantly hurrying from one weed-stalk to
another in search of insects. They prefer long grass and weeds, and, as their
flight is very low and straight, are hard to perceive. They live in pairs, and
during the breeding season the male is most pugnacious, driving away from
his nesting-place any stranger of the same species in a most determined way.
On one's approaching the nesting-placethe male has a peculiar habit of rushing
up into the air some zo feet, making a loud whiring noise (with its wings, I
fanry) to intimidate the intruder; at other times it is very shy and easily escapes
observation.
"The bird breeds at the beginning of November; the nest is cup-shaped,
placed some inches off the ground in a clump of weeds, several stalks being
interwoven in the structure, by which it is suspended.It is a minute bit of work,
Distributionand statusof the BeardedTachuri
379
being r in. x r in. deep in internal measurement,and composed of fine rootlets
thickly lined and interwoven with grass-down, so that it has a white
appearance.It is far superior to most nests in firmness and beauty. The eggs
are three in number; they vary $eatly in shape, but are of a uniform faint
yellowish tinge in colour."
Holland's data on timing of breeding in Argentina and on nest structure and
clutch-sizeare confirmed by Pereyra(1933,1938)and Nores and Yzurieta (1980),
who indicate that the nest is a small cup made of fine grass stems, rootlets,
thistledown and spiders' webs, almost always placed in the "cardo negro"
tlnislleCirsiumlanceolatum.
The same seasonalpattern existsin SdoPaulo, where
a pair was observedwith two fledglings at Itirapina on 9 December 1984(E. O.
Willis per T. A. Parker in litt. t99zl, and in Misiones, for which at least two and
possibly four of the seven April 1958specimensin AMNH are juveniles.
North of the Equator the regime is different but lessclearly known or defined.
Examination of birds collected in February in Roraima, Brazil, confirmed that
they were not breeding (D. F. Stotz in litt. t99), yet the testes of a January
male from Surinam were well developed while the organs of an adult specimen
in May were so small as to be unfindable (specimensin RMNH). A pair in the
Gran Sabanaappeared to be behaving territorially in April (M. Kessler in liif.
t99$. In Meta, Colombia, a male with testes 4 x z was collected in May
(FMNH) followed in June by a male with testes4 x 3 (IND), a juvenile female,
skull unossified (FMNH), and a female (IND) with a shelled egg in her oviduct
(as also reported in Hilty and Brown 1986); in December testes of a Meta
specimen(ANSP) were 1.5 x r, while the ovaries of one of two females(ANSP)
were 4 x z, and the bird was moulting. A male and female from Par6, June,
were in moult (Novaes 1967), and testes of a male from Amapii, July, were
3xz(Novaes1978).
The speciesis described as resident in Hilty and Brown (1986), and there
seems no reason to doubt that this is true of the short-winged breuipennis(see
Taxonomy below). However, the claim that nominate pectot"tlis
is non-migratory
(Short 1975)is contradicted by a century of testimony from Argentina, starting
with Holland (1891),who reported its arrival in October and departure in February, with confirmation provided by more recent observers(Daguerre r9zz, Pereyra t938, Nores and Yzurieta 1980,Nores ef rl. 1983,Narosky and di Giacomo
1993) - the first two of whom indicate November to March or April as the
period of summer residence- not to mention the entire body of dated specimen
material cited under Distribution.
The existenceor pattern of seasonaldisplacementfurther to the north is less
certain. Data from Misiones, Argentina, sugtest a similar breeding seasonbut
possibly year-round residence (at any rate, specimens as late as April and as
early as July). The dates of ro specimensfrom Chapada dos Guimaries - two
in May, two in July, four in August and two in September(Allen r89z) - might
indicate the species'suse of the areaas a winter quarters, but may merely reflect
chanceor collecting intensity. It is, however, notable that all dates given above
for nominate pectoralisfrom Brazil outside the southern statesof Sao Paulo and
Rio Grande do Sul are from May to October. Moreover, R. S. Ridgely (itt litl.
1995)points out that his observationscitherthan in SdoPaulo have usually been
of single birds, and always of silent ones, which tends to accord with austral
N. l. Collarand D. C. Wege
l8o
visitant status. If water is indeed significant in determining the distribution of
the species, it may well be that its presence in the pantanal region is linked
seasonallyto the flooding regime there: the dry seasoncausesthe grasslands
to be exposed from May to November, and the birds may then move in from
the much drier surrounding areas.
Population density, decline and threats
Wherever it has been found, the Bearded Tachuri has been characterizedas a
scarcebird. Recent reviews (e.9. Fieldsi and Krabbe r99o, Ridgely and Tudor
ry94) call it rare and local, and such judgement is repeated in many national
and regional evaluations: "very local" in Colombia (Hilty and Brown 1985),
"very scarce" on th€ Gran Sabanaof south-easternVenezuela (A. Altman and
C. Parrish perland.T. A. Parker in litt. r99z), "scarce" in Sipaliwini, Surinam
(Haverschmidt and Mees 1994),"scarce resident" in Uruguay (Gore and Gepp
1978), "definitely rare and perhaps endangered" in Paraguay (F. E. Hayes ir
Iitt. 1991),"scarce" in C6rdoba (Nores and Yzurieta r98o, Nores el aI. ry$),
"rare" in BuenosAires (Narosky and de Giacomo ryy\, and "scarceand local"
generally in Argentina (Pereyra 1933,M. Pearman in litt. r9go, T. A. Parker in
Iitt. r99z).
Nevertheless, there are places where the specieswas and is reported in at
least moderate numbers. Relatively recently it was judged fairly common in
part of Meta, Colombia (S. Furniss in Hilty and Brown 1986).In Roraima, Brazil,
it was "fairly common" (five birds collected and up to six seen in one day) in
a small patch of appropriate habitat in early r99z (D. F. Stotz in l;tt. 199:'. ln
C6rdoba, Argentina, there is a single area - Bafradosdel Rio Dulce - where it
is consideredmoderately frequent (Nores and Yzurieta 1980,Nores el ,1. 1981).
At Itirapina in Sio Paulo state, Brazil, Willis (1992)reported six in one day, and
R. S. Ridgely (in litt. rg94\ recently found it more numerous than anywhere he
had previously encounteredit. It is possible that the relatively high representation of Guyanan specimensfrom Mount Roraima reflects fair numbers in pristine areas on isolated tepuis (T. A. Parker in litt. 1992\ and the collection of
seven specimensin July r93o from Campo Grande in Brazil, and of r5 specimens
in two short periods in 1958at Arroyo Urugua-i, suggestslocally solid populations. Conversely, extensiveareasof apparently suitable habitat, such as those
in Rio Grande do Sul and eastern Entre Rios, have yielded no records (T. A.
Parker iz litt. t992, Pearmanand Abadie ry95\, and within Emas National Park,
clearly one of its strongholds, the speciesseems to be confined to a few small
areas, the entire population (if resident) being judged very small, "doubtfully
exceedinga few hundred individuals" (T. A. Parker in litt. t99z).
This seeming patchinessis mirrored in the historical record. At Santa Elena
in Uruguay in November tggz only two were encountered (Aplin r89z), yet in
the same month of the same year at another Santa Elena, in Argentina, it was
"fairly common" (Holland 1893);and although at Sapucai,Paraguay,the single
bird collected was the only one encountered in a three-year period (Chubb
1910),it was "not rare" in late 1883in Paysandri, Uruguay (Gibson 1885).
The size and behaviour of the BeardedTachuri may be a significant influence
in general assessmentsof its status. Despite their concern that it may be
Distributionand statusof the BeardedTachuri
181
threatened, Ridgely and Tudor (1994)admit that it is inconspicuous and therefore "probably often overlooked", and two recent observers of the nce breaipenrls independently approach this conclusion. In Venezuela M. Kessler (iz
Iitt. rgg4 obtained his April 1994records casually during botanical work, and
therefore tentatively suggests that the speciesmay not be rare in the central
Gran Sabana.In Colombia F. G. Stiles (in litt. 1994 "was impressed with what
a difficult bird it is to see from any distance", as "it rarely perches as much as
a metre above the ground or water and its sallies are likewise short and low";
he too speculatesthat it may not really be rare so much as greatly overlooked.
There is, moreover, the important testimony of Holland (1893),quoted above,
which indicates precisely the same habits in the race pectoralis(and emphasizes
the temporally patchy nature of its unobtrusiveness), and of one observer in
Emas National Park who refers to the species'shabit of keeping low in vegetation and being frequently lost to view (R. Schofieldin litt. t99$. On one occasion
a bird was observedactually spending time on the ground, although also often
clinging to grass stems near the ground (R. Hopf in litt. t99$.
Changesin the status of the Bearded Tachuri must inevitably have occurred
over the past century. Although there are areaswhich appear to remain as yet
unaffectedby human development (Meta is one: F. G. Stilesir lilt. 1994),FjeldsA
and Krabbe (r99o) report that the species'ssavanna habitat is being destroyed
everywhere, Ridgely and Tudor (1994)indicate that overgrazing and frequent
burning has reduced such habitat to a few scatteredsites, and F. E. Hayes (ln
Iitt. 1991)identifies the problem in Paraguayas the loss of pristine grasslandto
agriculture and livestock grazing. More general accounts of the loss of habitat
within the bird's range are in Bucher and Nores (r988), Cavalcanti(r988), Fjeldsn
(1988), and Willis and Oniki (1988). Nevertheless, cases where the Bearded
Tachuri has indisputably suffered decline or local extinction are few, and this
reflectsthe general dearth of information on the modern status of South American grasslands.There is the loss of r. Natterer's site, Calgdodo Couro, to urban
expansion in Sio Paulo (see above), and the San Martin mate plantation in
Misiones, Argentina, now flooded by a reservoir (i. C. Chebez in litt. r99).
There is the endangermentand possibleextinction of the Andean race bogotensis
(see below). Recent searchesby T. A. Parker (ir litt. ag92)in remnant, but
seriously degraded grasslandsaround Santa Cruz, Bolivia, were unsuccessful,
and in his experiencedview the present statusand future of the BeardedTachuri
"would appear to mirror the situation of the Greater Prairie Chicken Tynpanuchuscupidoin the Great Plains of North America, that is, both are species
that occur in numerous, widely scatteredpopulations that survive (primarily)
in suboptimal habitats".
The rnost unequivocally threatened population of the speciesis on the montane plateau of Colombia. The statement that bogotensis
has not been found at
all in over 50 years (Ridgely and Tudor 1994)appears to be based on a similar
one made r5 years earlier by King (1978-1979),who was evidently using the
date of the most recent publication in his referencelist on the species(Cory and
Hellmayr 1922)to establish this time-lapse. In fact, F. G. Stiles (in litt. a99+)
reports two specimensin the Museo de la Salle, Bogote, apparently collected
in the 195os,and has twice seen small brown flycatchersin remnant marshes
in the Bogot6 area, too distant to identify, although J. FjeldsAsearchedfor it in
N. I. Collarand D. C. Wege
3,8z
r98r without success(in Collar and Andrew 1988).It is clear that if indeed any
birds of this race survive their numbers must, as Kng Q978-rg79) stated, be
very small. Although Kng Qg78-t979\ expressedmystification as to the cause
of its rarity, FieldsA(1988)blamed extensivedrainage and conversion of habitat
(factorsof equal significancein the loss of the Colombian GrebePodicepsandinus
and the endangerment of the Bogote Rail Ra/lls semiplumbeus
and Apolinar,s
Wren Cistothorusapolinari:see Collar el al. r99z).
Evaluation of conservation status
Since the inception of IUCN's Red Data Book programme in the mid-r96os,
qualitahve criteria provided compilers of information with guidelines for the
listing and categorizationof taxa. These criteria, with their unspecific reference
to impending extinction, near futures and likelihood of deterioration, remained
fairly constant over the zo-yearperiod r974-a993,during which tirne the opportunity to classify the Bearded Tachuri as threatened arose three times (in King
1978-7979,Collar and Andrew 1988,and Collar et al. ry92\, and was accepted
only on the second occasion,in the course of a very preliminary and cursory
review. The fuller evidence assembled during r99r-r992 suggested that this
listing was mistakenly cautious: with populations spread acrossso large an area
of South America, particularly when some of these appeared relatively secure,
little justification appeared to exist for believing that the specieswas as yet in
danger of global extinction or likely to reach that condition in the "near" future.
Given, however, the many referencesto its scarcity and to the loss of so much
of its habitat, it was clearly a serious cause for concem and hence a candidate
for continuous monitoring, a circumstance for which the unofficial but very
practical category "near-threatened" had been developed (Collar and Stuart
1985:7o8,Collar and Andrew t988: xi-xii, Collar ef nl. r9g2 1.047,rgg4 zzz\.
During the early r99osexplicit, quantitative criteria were developed by IUCN
againstwhich to measurethe conservationstatus of species.Sincein the process
of becoming extinct a speciesmust inevitably decline in numbers and contract
in range, numerical thresholds were establishedto promote a more consistent
and obiechve classificationof extinction risk using these variables. In the new
criteria, the three (alternative)key thresholds dividint "threatened" from ',nonthreatened" are <1o,ooo for the number of mature individuals (this number
must also be cunently in decline), <uo,ooo km'?for the extent of their occurrence
(which again must be diminishing), or a rate of decline, irrespectiveof absolute
population size, in excessof 2oEa over 10 years. Collar ef al. (tg94) $ve an
abbreviationof thesecriteria, which are fully set forth in Mace and Stuart (r94),
although the final version adopted by IUCN - containing the rate of decline as
expressedabove - remains to be published.
There is clearly no question thai the BeardedTachuri fails to meet the rangesize threshold, and we think it reasonable to assume that so small a bird
extending over so massivea range must possessmore than 1o,ooomafure individuals: to use the kind of argurnent deployed by Remsen (1995, this issue),
even a density of only one pair per 5 km'?would be enough to reachthe required
level h the Gran Sabanaalone. Nevertheless,extrapolationbasedon local densities (even if any such data were available)is unwise for very patchily distributed
Distributionand statusof the BeardedTachuri
l8l
species;moreover, as many of the localities detailed under Distribution must
by now be lost, any judgement of total population size will be undisguisably
purblind. As for a decline of zoVoin the past 10 years (or proiected for the next
ro years), this is less likely to be measured in terms of numbers, especially for
lessfrequent tropical species,than by inferencefrom considerablecircumstantial
evidence. In this case,despite specificexamplesof habitat loss within the bird's
range, it remains doubtful (to us) that such an averagecan have been achieved
or is likely to apply. A more appropriate classification seems to be "nearthreatened", since it would be far less easy to deny (sayl a rcVo decline over
the last or next zo years, or (say) a population of <zo,ooo mature individuals.
However, if the three subspeciesare (a) acc€pted as such (see Taxonomy
below) and (b) subjected independently to these criteria (since the criteria can
be applied to both speciesand subspecies),the form bogotensis
would clearly
qualify at once, as indeed it had already done under the old criteria in King
(19TU197 , and it might well be that pectoralisand., with the application of
"responsible pessimism" (Collar e, al. t994 t7-t8), conceivablyeven brnipennis
could each also be assignedthreatened status. This circumstancehighlights one
of the curiosities of any evaluation system: that the criteria may admit every
subspeciesof a specieseven while rejecting the speciesitself. lt mitht then be
asked if it is right that, when threatened subspeciesare sufficiently disjunct in
range or distinct in ecology from each other for their fates to be entirely independent, the surn of their separate numbers or ranges should disqualify the
speciesas a whole frorn sharing their status. Atainst this it can be argued that
the probability of extinction must diminish with increasing number of populations (taxonomically distinct or not), and that the fate of the speciesmust be
evaluated against a set of absolutesif significant distortions are not to enter the
sysrem.
Another area of debate concems the weight to be given to existing conservation measures for a species, most notably the (usually accidental) protection
achievedthrough its occurrencein parks and reserves.The new criteria include
the (non-threatened) category "Conservation Dependent" for species whose
fate is directly linked to the continuation of prograrnmesof active management.
This is clearly not the casefor the BeardedTachuri, but it may yet be so if, over
the coming century, conservation policy for grassland speciesbecomes more
fully integrated with agricultural development programmes.
Currently, however, the species is inadequately represented within the
existing network of protected areas. Although we cannot be sure that some of
the sites listed under Distribution above are not protected, the only ones known
to be so are as follows: (Verczuela)Canaima National Park (3,ooo,oooha) which
embraces most of the records from the tepui region (IUCN r9z); (Surinam)
Sipaliwini Nature Reserve (roo,oooha), also important for the threatened
Rufous-sided Pygmy-tyrant Euscarthmusrufomarginntus(Wege and Long in
Wep.); (Brazil) Tumucumaque Indigenous Park, Pard (z,Vn,un ha), which is
contiguous with Sipaliwini Nature Reserve(IUCN r99z); Chapada dos Guimaries Nahonal Park, Mato Grosso (33,oooha: IUCN r99z); Emas National Park,
Goids (13r,868ha) which is important for seven threatened bird speciesincluding Lesser Nothura Notftara minor (Wege and Long in prep.); Itirapina State
EcologicalStation (z,3ooha), one of the largest remaining fragments of "campo
N.l. Collarand D. C. Wege
384
cenado" in SdoPaulo, important for the threatenedLesserNothura and Rufoussided Pygmy-tyrant (Wege and Long in prep.) and also the near-threatened
Sharp-tailed Grass-tyrant, Cock-tailed Tyrant, White-banded Tanager Neoiftraupis fasciataand White-rumped Tanager Cypsnagrahirundinacu (Collar et al.
lggz); (Paraguay)ReservaNatural del BosqueMbaracayn (62,979ha) which supports populations of nine threatened species(Wege and Long in prep.); Reserva
Tati Jupi (no information); (Argentina) the new Mburucuyii National Park,
important for four threatened species(Wege and Long in prep.); Costaflero del
Sur Natural Park (74,oooha) (IUCN r99z); Baflados del Rio Dulce and Mar
Chiquita Natural Park (5o,oooha), also important for three threatened species
(Wege and Long in prep.); and Otamendi National Scientific Reserve(2,632ha:
IUCN r99z).
Taxonomy
There is confusion over the distinctivenessof the subspeciesof PolVstktuspectoralis.ln view of Fjeldsi and Krabbe's (r99o) remark that the northern subspecies, being very small and with no distinct throat markings, may be specifically
distinct from nominate pectoralis,we briefly review opinions on the taxonomy
of the species,as the subject clearly bears on conservationdecision-making(see
above). Some of these issues may in due course be illuminated by a study of
the little known and, accordingto R. S. Ridgely (in lltf. 1995),infrequently heard
voice of the speciesfrom various parts of its range.
von Berlepschand
In fact Sclater(1888)and then the describersof breaipennis,
Hartert (r9o9), were fairly emphatic in finding no differencesin lowland birds
north of the Equator from those to the south other than in size (the measure of
which was in the wing, tail and bill). It was Cory and Hellmayr (t927) who
considered thal breaipennisdiffers from pectoralisnot only by smaller size and
feather length but by less developed crest, and less black on cheeksand throat.
Even so, such feafures advance no real case for the separation of breztipennis
from pectoralisal the specieslevel: the distinction may be one that chiefly reflects
migratory (onger wings) as against sedentary status (in this regard it would
worth checking if all nominate pectoraliswing-lengths fall outside the range for
breaipennis,
or whether the more northerly populations of pectoralis,atleast some
of which may not be migratory, approach brnipennis in this character).
The situation is complicated by variation within bretsipennis
itself. Novaes
(1967)noted more black to the chin and throat and a more ferruginous wash to
the rump in birds ftom Par6 than in one from Roraima, Brazil. Four FMNH
birds from Meta. Colombia. are rnuch darker crowned and darker faced than
(other) birds from Roraima, Brazil (D. F. Stotz in litt. t99). Five AMNH birds
from lowland Annai (96 m according to Stephens and Traylor 1985),Guyana,
are generally paler (almost whitish on the throat and centre of belly) than five
birds there from upland Cerro Roraima, Venezuela, some or all of which were
collected at over 1,ooom, and one of which (z358or) is so saturated as to be
(T. S. Schulenbergin litt. t99).
barely distinguishable from bogotensis
This finding further confuses the caseof bogofensis,
suffering as it does from
the paucity and dispersion of the museum material on which it is based. Chap-
Distributionand statusof the BeardedTachuri
)85
man (r9r5, also r9t7), using a single male, referred to its being "more richly
colored throughout" (its size being between pectolalis and brnipennis), and.
becauseit was "a form of a Tropical Zone speciesapparently isolated on the
TemperateZone Savannaof Bogot6", he was tempted to treat it as a full species.
Wetmore (1926)took this view, citing not only the "much more rufescentcoloraIion" of bogotensis
but also its "wholly black bill, so that it seemsto represent a
distinct species". Cory and Hellrnayr (1927)added that bogotensis
is nearest to
pectoralisand.aboLttthe samesize, but with crown feathersmuch more elongated
and narrower, back much more tawny, wing bands and edges of remiges deep
tawny instead of tawny ochraceous,superciliariesbright buff instead of pure
white, and so on.
However, these latter reported no difference between representativesof pectoralis and.the single lemale bogotensis
that Hellmayr was able to inspect and
which, in fact, he only assumed to be ascribableto bogotensis
on the basis of its
provenance (Dagua). The variation wilhin breoipennis,
in particular the convergenceof some specimenson bogotensis,
suggeststhat the situation is more complex than the current arrangement allows, and that much more work is needed
before parhcular features can be identified as the basis for a constant racial
character.For example, the significanceattached by Wetmore to the black bill
of bogotensis
is lost alongside Sclater's description of pectoralis'sbill as "black
above, slate below". Clearly as it stands the evidence of the specific distinctivenessof bogolensis
is wanting.
There also appearsto be some variation within nominate pectoralis.The taxon
Pachyramphus
minimuswas shown by Hellmayr (1925)to be invalid, although it
was iudged a distinct raceof pectorslisby Allen (1889),basing himself on Gould's
(misleading)plate, which is merely an adult male "in high plumage". Nevertheless, Wetmore (1926)found a female taken by T. J. Page on the Parana (the
Irarana bird) to be browner on the underparts and larger in bill than another
from Puerto Pinasco,Paraguay;and Cory and Hellmayr (1927)speculatedthat
birds from Brazil might never be so black about the head as those fiom the
other countdes in the race's range. There has, however, been no subsequent
move to separateany populations of nominate pectoralisas distinct subspecies.
There are two conclusions to draw from this brief review. The first is that it
is inappropriate to continue to promote the idea of specific identity for any of
the races of Polystictuspectoraliswithotrt the assemblyand rigorous analysis of
an extensiveseriesfrom all parts of its range. Even the subspecificidentities of
bogotensis
and breaipennis
need further study and validation. The second is that
the discipline of wildlife conservation cannot function independently of the
discipline of formal taxonomy. The extensivelist of institutions furnishing specimen data for this study (see Appendix below) is one token of the relevanceof
museums to conservation;but the fact that we still cannot be sure which taxa
compose the subiect of this paper illustrates the cardinal importance of continued biological and taxonomic investigation by museums. It is taxonomistson
whom conservationistsdepend for the knowledge of what there is to be conserved. Modern conservation requiresworking museums, In one real sense,
therefore, the fate of the Bearded Tachuri itself is linked, ultimately, to the fate
of the institutions that hold the material eyidence for its existence.
N, I. Collarand D. C. Wege
386
Acknowledgements
All orators and assistantsat the museums whose label data are cited in this
paper are warmly thanked for their help and hospitality; K. C. Parkesprovided
the CM data personally and offered critical commentary on this material.
D. F. Stotz critically reviewed the typescript twice, and added his records.
T. S. Schulenbergand R. S. Ridgely commented on the typescript, the former
also fumishing label data from AMNH and the latter adding his records. M.
Pearman furnished label data from MACN and all his records from Argentina.
F. E. Hayes supplied the great majority of locality records from Paraguay,
R. P. Clay and J. C. Lowen supplementing them. M. Babarskas,J. C. Chebez,
B. M. L6pez Lanus, M. Nores and D. Yzurieta provided important material
from Argentina, and E. Bucher helped with several points. F. G. Stiles contributed data from Colombia. L. P. Gonzaga, M. L. Goodwin, G. F. Mees and
E. O. Willis each added material at various stages.D. K. Dacol, B. C. Forrester,
R. Hopf, M. Kessler, R. Ryan, R. Schofield, H. W. Wallis, A. Whittaker and
B. E. Wright responded to the request made in Cotirga r:48 for their records.
M. J. Crosby, G. M. Mace and A. J. Stattersfieldreviewed part of the typescript.
Librarians F. E. Warr (BMNH), L. Giddings (Royal Society for the Protection of
Birds) and A. Rawlins (University Library Map Room, Cambridge) responded
promptly to requestsfor help. We acknowledge the great kindness of all these
PeoPle.
Appendix
AMNH : American Museum of Natural Historv; ANSP = Academv of Natural
Sciencesof Philadelphia;BMNH = Natural i-listory Museum, Tring, U.K.;
CM = Carnegie Museum of Natural History; CMN = Canadian Museum of
Nature; COP = Colecci6n Omitol6gica Phelps, Caracas; FMNH = Field
Museum of Natural History; IND : Unidad Investigativa Federico Medem,
INDERENA, Bogotri;LSUMZ : Louisiana State University Museum of Natural
Science;MCZ = Museum of Comparative Zoology; MHNG= Mus6um d'Histoire Naturelle, Geneva; MNHNM = Museo Nacional de Historia Natural,
Montevideo; MNRJ = Museu Nacional, Rio de Janeiro;MPEG : Museu Paraense Emflio Goeldi; MZUSP = Museu de Zoologia, Universidade de 56o Paulo;
RMNH = Riiksmuseum van Natuurlijke Historie, Leiden; ROM = Royal Ontario Museum; UMMZ= University of Michigan Museum of Zoology; UNP =
Universidad Nacional de la Plata; USNM = United States National Museum;
YPM : Peabody Museum, Yale University; ZSM = Zoologlsche Staatssammlung, Munich.
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