Ortalis Wagleri)’
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The Condor92349-753 0 The Cooper Omitholo&il Society 1990 TAXONOMIC STATUS OF THE RUFOUS-BELLIED CHACHALACA (ORTALIS WAGLERI)’ RICHARD C. BANKS BiologicalSurvey Group, National EcologyResearch Center, U.S. Fish and Wildrife Service, National Museumof Natural History Washington,DC 20560 Abstract. The Rufous-bellied Chachalaca,Ortalis wagleri, of northwestern Mexico was merged with the morphologicallydifferent West Mexican Chachalaca,Ortalis poliocephala, on the basis of hybrids taken in the vicinity of Puerto Vallarta, Jalisco (Moore and Medina 1957). Eight specimens from that vicinity vary in appearance chronologically, from an individual similar to wagleriin 1892 through skins appearingto be F, hybrids in 1955 to birds nearly indistinguishable from poliocephala in 1961. There is no other evidence of contact between the two forms. This is deemed insufficient evidence for considering the forms conspecific,and I recommend that Ortaliswagleri be restoredto the statusof species. Key words: Rufous-belliedChachalaca; Wagler s’ Chachalaca;Ortalis wagleri; WestMex- ican Chachalaca;Ortalis poliocephala;Mexico; hybridization:taxonomy. INTRODUCTION Amadon (1973) suggestedthat the two forms Chachalacas(Or&is spp.) are economically im- might actually be distinct. portant game species throughout their collective The genus Ortalis is a difficult group, consist- range in Latin America. Like their larger and ing of 1O-l 2 very similar species,mostly mono- more showy relatives in the family Cracidae, the typic and mostly allopatric. Those that overlap guans and curassows, many chachalacas are suf- geographicallygenerally do so in limited fashion, fering from reduced population levels because of at only one or a few localities (Delacour and overexploitation and habitat loss; several species Amadon 1973). Very little hybridization is known in the family are considered endangered.Despite (Vuilleumier 1965), despite the overall similar- this, many aspectsof the biology of the cracids ities among all the species.It has even been sug- are poorly known-including their taxonomic and gestedthat the entire genus constitutes a super- evolutionary relationships. species (Amadon in Mayr and Short 1970). From the time of its description in 1867 until Difficulties of classification in the genus are in- 1957, the Rufous-bellied or Wagler’s Chacha- dicated by the AOU (1983), in which notes pre- laca, Ortalis wagleri, of northwestern Mexico was senting alternative taxonomic treatments are considereda distinct species.The more southern given for each of the four species listed. One West Mexican Chachalaca, 0. poliocephala, sim- changein the taxonomy of the Central American ilarly was considered distinct for most of its group has already been made, namely the ele- named existence,although from about 1934 until vation of 0. leucogastrato the specieslevel (AOU 1953 it was ranked as a subspeciesof the Plain 1985). Chachalaca, 0. v&da (Griscom 1934, Hellmayr DIFFERENCES BETWEEN 0. WAGLERZ and Conover 1942, Ridgway and Friedmann AND 0. POLIOCEPHALA 1946, Wagner 1953). Just when the specific dis- tinction ofpoliocephala was reconfirmed, wagleri Ortalis wagleri is distinctive in the genus in hav- was merged into it as a subspecies(Moore and ing the abdomen and the tips of the tail feathers Medina 19 5 7). This taxonomic statuswas main- rich chestnut. The speciespoliocephala, on the tained by Vaurie (1965, 1968) and is reflected other hand, is whitish or grayish white on the by the AOU (1983), although Delacour and underparts and tail tips, although most individ- uals have a wash of buff or rufous on the thighs or abdomen and on the tips of the rectrices.Even I Received12 January 1990. Final acceptance3 May though he treated these forms as conspecific, 1990. Vaurie (1965, p. 12) noted that they represent [7491 750 RICHARD C. BANKS [spectrograms]of wagleri from Nayarit . show some similarity to the spectrogramsofpolioceph- ala but not very much.” Neither of these studies is definitive or convincing. EVIDENCE FOR THE MERGER The evidence to support the merger of these two distinctive Mexican forms (Moore and Medina 1957) consisted of a small series of birds from the vicinity of Puerto Vallarta, Jalisco, near the border of Nayarit, that seem to be hybrids or intergrades. The earliest Puerto Vallarta speci- mens had been used to set the southern limit of wagleri at about the border of Nayarit and Ja- lisco. Aside from specimensfrom the Puerto Val- 0 1 I I I I larta area, there is a large gap in the documented KMS range of the two speciesfrom San Blas and Tepic, Nayarit, along the entire coastofJalisco to north- FIGURE 1. Map showingnearest documented lo- em Colima (Ridgway and Friedmann 1946). calitiesof Ortalis wagleri(dots) and 0. poliocephala (Note: Vaurie, 1965, p. 17, mentioned a tape of (triangles)in westernMexico. The hybrid areain the calls attributed to 0. wagleri made 34 miles vicinity of PuertoVallarta is indicatedby a square.An northeast of Puerto Vallarta, Jalisco. This ap- uncertainrecord is markedby ?; seeparenthetical note on p. 750. pearsto be in the valley of the Rio Ameca, about 30 miles northwest of Amatlan, Nayarit. Spec- trograms of those calls, however, were consid- the extremes of color variation in the genus. The ered very different from those of calls of wagleri two forms are similar in size, being the largest from farther north and were not similar to those members of the genus. In wagleri, the bare facial of calls of poliocephala. The identity of the bird skin around the eyes is blue, and the bare throat recorded, but apparently not collected, is in red, whereasinpoliocephala both the bare orbital doubt.) There seems to be a similar gap inland, and gular skin are “carmine” (Delacour and the nearest documented approach of the two Amadon 1973); these facial differencescould aid forms being between Amatlan, Nayarit, and in reproductive isolation. Whereas poliocephala Guadalajara, Jalisco (wagleri), and Autlan and is a bird of higher, moister broad-leaved decid- Los Masos, Jalisco (poliocephala), distances of uous forest in the major part of its range in south- about 150 km or 80 miles (Fig. 1, Vaurie 1965). em Mexico, wagleri, in northwestern Mexico, is If this separation is real, and not an artifact of a bird of much drier vegetation at lower eleva- incomplete collecting, it is as large as the gap tions. between any two neighboring populations in the There may also be vocal differences between North American range ofthe genus(Vaurie 1968, wagleri and poliocephala. Davis (1965) reported Delacour and Amadon 1973). on the voices of most members of the genus Or- Moore and Medina (1957) artificially closed talk and concluded that the vocalizations of wag- the distributional gap between the forms by new- leri and poliocephalawere more like one another ly naming the population of poliocephala from than either was like other species.However, the Colima 0. p. lajuelae, and by including some of differences were great enough so that he called the Puerto Vallarta specimensin the range of this them separate,but sibling, species.Vaurie (1965, subspecies.This new subspecieswas supposed p. 16) also discussedthe voices of these birds, to differ from more southern poliocephala by using Davis’s tapes. He felt that “the ‘song’ of being darker below, varying in the direction of wagieri . sounds very similar to that of poli- wagleri. Few later authors (e.g., Schaldach 1963) ocephala.” However, “the spectrograms pre- have recognized that subspecies,but even those pared from the tapes of wagleri did not confirm who have not recognizedit have followed Moore the very close similarity to poliocephala . .” and Medina (1957) in stating that the population Vaurie (1965, p. 17) went on to say that “five is intermediate between true poliocephala and TAXONOMY OF RUFOUS-BELLIED CHACHALACA 751 wugleri (Vaurie 1965, 1968). Delacour and Ama- other specimens were taken in the vicinity of don (1973) recognized the race deliberately to Puerto Vallarta in 1961 by Peter R. Grant and call attention to the supposedintergradation. Of are now in the Cowan Vertebrate Museum of the course,the redefinition of the range ofpolioceph- University of British Columbia (UBC). I have ala to include Puerto Vallarta establisheda point studied all eight of these specimens, along with of contact with wagleri, already stated to occur the series from within the recognized ranges of south to that area. Reiteration of the concept of poliocephala and wagleri in the U.S. National contact has reinforced the idea of intergradation Museum of Natural History (USNM) and all from Colima northward through Jalisco,and thus specimens in the AMNH. supported the proposal that the two different Descriptions of these eight specimens follow, forms represent a single species.This reinforce- as compared with “typical” 0. wugleri (USNM ment has taken place despite the lack of speci- 164438, male, Chacala, Durango, ~011.by E. A. mens from the rest of the supposed intergrade Goldman, 24 Feb. 1899) and 0. poliocephala zone or additional material that is intermediate (USNM 185335, male, Papayo, Guerrero, ~011. morphologically. by E. W. Nelson and E. A. Goldman, 19 Apr. I cannot recognizethe existenceof a subspecies 1903). Becausethe forms are essentially identical of poliocephalafrom Colima northward through dorsally, only the ventral surfacesare compared. Jalisco that differs from southern birds by being AMNH 471460, female, Las Petias, Jalisco, darker below. Specimens of poliocephala in the ~011.by A. C. Butler, 7 Mar. 1892. Similar to southern part of the range have more color than wugleri ventrally but paler, the abdomen, cris- Moore and Medina (1957) and later authors sum, thighs, and tips of rectrices (except central, (Vaurie 1965, Delacour and Amadon 1973) have in each description) dark rufous rather than rich admitted. Many birds from Michoacan, Guer- chestnut. Lower neck and breast gray as in po- rero, and Oaxaca have extensive buff or rufous liocephala rather than brown as in wagleri. on the flanks, posterior lower parts and tail tips, AMNH 47 146 1, female, Bahia de Banderas, and match Colima birds in this respect.