Carduelis Spinescens), with Comments on Its Status in Ecuador
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\ SHORT COMMUNICATIONS ORNITOLOGIA NEOTROPICAL 5: 61-63, 1994 @ The NeotropicaI OmithologicaI Society GEOGRAPHIC VARIATION IN THE ANDEAN SISKIN (CARDUELIS SPINESCENS), WITH COMMENTS ON ITS STATUS IN ECUADOR Mark B. Robbins' *, Niels Krabbe2, Gary H. Rosenberg3 & Francisco Sornoza Molina4 1 Dept. of Ornithology, Academy of Natural Sciences, 1900 Benjamin Franklin Parkway, Philadelphia, Pennsylvania 19103. U.S.A. 2Zoological Museum, University of Copenhagen, Universitetsparken 15. DK-2100 Copenhagen 0, Denmark. 38101 N. Wheatfield Drive, Tucson, Arizona 85741, U.S.A. 4 Museo Ecuatoriano de Ciencias Naturales, Casilla 8976- Suc. 7. Quito, Ecuador. Key words: Carduelis spinescens, geographic variation, Ecuador. In March 1992, an expedition by the Academy the northern end of the Western and Central of Natural Sciences, Philadelphia (ANSP), and Colombian Andes from Antioquia south to the Museo Ecuatoriano de Ciencias Naturales Cauca and western Putumayo. We know of no (MECN), Quito, found Carduelis spinescensto be confirmed records for eastern Nariño, but un- relatively common in páramo and in clearings at doubtedly nigricauda does occur there, given Cerro Mongus, Prov. Carchi, Ecuador (00 °27'N , that it is now known from just across the border 77°52'W; Robbins et al.1994). In attempting to in Ecuador (see below). determine the subspecific affinities of these The nominate race and capitaneus are indis- birds, we found that the recent literature has in- tinguishable in plumage morphology, and, as correctly portrayed the distribution of the three Todd (1926) pointed out, the purported diffe- described forms (Howell 1968, Hilty & Brown rence in size between these forms is not sup- 1986, Fjeldsa & Krabbe 1990), and overlooked ported when examined in a series (Table 1). The that the subspecies C. s. nigricauda is nearly se- supposed more dusky or olivaceous cast to the xually monomorphic in plumage (Hilty & lower underparts of adult male capitaneus, in Brown 1986, Ridgely & Tudor 1989, Fjeldsa & comparison with the clearer yellow of spinescens, Krabbe 1990). .The following review is based on also does not hold up when a series of these two having examined 103 C. spinescensspecimens in taxa are compared. Perhaps the only reason for United States museums and the MECN. maintaining the name for the Santa Marta birds There are three described forms of C. spines. is that through their isolation they presumably cens. The nominate race is found from the have diverged genetically from nominate spines- coastal mountains of northern Venezuela, the cens. However, the Perijá population is just as western Venezuelan Andes (Mérida, Trujillo), isolated as the Santa Marta birds, but is assigned and the Perijá Mountains on the Venezuela-Co- to the nominate race. Thus, for consistency's lombian border, south along both slopes of the sake, we recommend that capitaneus be synony- Eastern Colombian Andes to Cundinamarca. mized with spinescens. Capitaneus is restricted to the Colombian Santa All specimens referable to the nominate form Marta Mountains, and nigricauda ranges from (now includes Venezuelan, Santa Marta and * Presentaddress: Division of Ornithology, Museum of Perijá mountains and Eastern Andean Colom- Natural History, Univ. of Kansas,Lawrence, KS 66045, bian birds) are strongly sexually dimorphic in U.S.A. plumage (see color plates in Hilty & Brown 61 \ SHORT COMMUNICATIONS TABLE 1. Selected measurements (in mm; x :t SD) of Carduelis spinescenssubspecies. Subspecies bill wmg tail (exposed) (chord) (longest rectrix) 9.8 (+0.8) spinescens 61 41.1(+1.6) 10.0 ( +0.3) 42.4 (+1.1) capitaneus 14 nigricauda male . 13 10.3 ( +0.7) 71.1 (+1.2) 41.9 (+1.2) female 15 10.6 ( +0.5) 69.3 ( + 1.0) 40.9 ( + 1.0) 1 Sexesare pooled for spinescensand capitaneus, as there are no significant differences between the sexesin the above measurements. Measurements for both sexesof nigricauda are given as males have significantly longer wings than females (P < 0.001; two-tailed, t-test). Nigricauda sample includes all Ecuadorian specimens. 1986, Fjeldsa & Krabbe 1990), and have rela- Our Cerro Mongus specimens and an adult tively large amounts of yellow at the base of the male taken ca. 25km to the northeast (Cocha rectrices. Adult male spinescensalso have brighter Seca, Ooo38'N, 77°40'W; G.R. Graves, M.J. yellow underparts than nigricauda adult males. Braun, pers. comm. ) are closest to nigricauda, In contrast, the plumage differences between the with both adult sexes having dark caps, olive- sexes of nigricauda are only minor (Chapman yellow underparts, and relatively little yellow 1912, Todd 1926), with the primary difference at the base of the tail. Nevertheless, the Cerro being that adult females have a sooty brown cap, Mongus birds do differ from the Colombian whereas the crown is black in adult males. Both nigricauda and the Ecuadorian El Angel birds sexesof nigricauda have only a hint of yellow at in two characters. The cap color of Cerro the base of the inner rectrices, ranging from Mongus adult females is virtually identical to virtually none in Colombian birds to small that of Cerro Mongus adult males, i.e., it is traces in northern Ecuadorian birds. Even in the black. Both sexesof the Cerro Mongus material most marked Cerro Mongus individuals, the yel- have yellow in the tail, although still considera- low is only discernible when the upper tail bly less than spinescens, which is absent or coverts or crissum feathers are pulled completely nearly so in Colombian nigricauda and the out of the way. two Ecuadorian El Angel birds. Yellow is not Carduelis spinescens was first recorded in found in the outermost and the central pair Ecuador near the Colombian border in páramo of rectrices in the Cerro Mongus and Cocha at Volcán El Angel, Prov. Carchi, in January Seca birds, but all three Cerro Mongus adult 1982 by P. Greenfield et al. (Ridgely & Tudor males have discernible yellow at the base of 1989). The first specimen was obtained by the 2nd through 5th pair of rectrices, whereas Krabbe (1992) in November 1990 at El Angel, the Cocha Seca bird has yellow at only the followed by another specimen from there in base of the 2nd rectrix. All five adult Cerro November 1991 (MECN 5745,6000). Both speci- Mongus females have yellow in the 3rd through mens are adult females and were assigned to the 5th rectrices. The extent of the yellow is nominate form. Reexamination of those speci- variable, with the 3rd rectrix pair averaging mens indicates that the birds are undeniably the most amount of yellow. It is unclear whether attributable to nigricauda. The El Angel birds, the slightly greater amount of yellow at the especially MECN 5745, have a brownish-black rectrix base of the Cerro Mongus/Cocha Seca cap like that of adult female Colombian nigricau- birds, as compared to Colombian nigricauda, da. Furthermore, one bird completely lacks any is apleisomorphic character within the nigricau- yellow in the tail, and the other has only a hint da populations, an incipient character arising of yellow at the base of the third and fourth rec- within the Ecuadorian population, or obtained trix on the left side only. Thus, in this feature the through hybridization with sympatric C. magel- El Angel birds resemble the Colombian birds lanica. No other plumage characters indicated more than they do the Cerro Mongus series (see hybridization between these taxa at Cerro Mon- below). gus/Cocha Seca. 62 \ t SHORT COMMUNICATIONS ( í- Although the entire Cerro Mongus series and ACKNOWLEDGEMENTS the Cocha Secabird are~eparable from all other Our work in Ecuador was supported by a grant known forms of this species, we refrain from from the MacArthur Foundation. We thank our naming it for the following reason. Carduelis are friends at the Museo Ecuatoriano de Ciencias known for being highly mobile and nomadic, Naturales, Quito, for logistical assistance. The and given that C. spinescensregularly occurs in Ministerio de Agricultura, Quito, especially .assorted ty.pes of second growth vegetation as Sergio Figueroa, provider authorization for our I lowas 1800m (Hilty & Brown 1986), it is concei- work in Ecuador. Aldo Sornoza Molina kindly vable that birds found in extreme eastern Carchi provided valuable field assistance.The following (Cerro Mongus) and western Sucumbios (Cocha people and institutions provided accessto speci- Seca) may come into contact with the El Angel men material: Gary Graves and Michael Braun, population, that is only ca. 40 km away. A larger National Museum of Natural History, Smith- sample from the latter area may eventually show sonian Institution; Mary LeCroy, American that there is minimal plumage differences be- Museum of Natural History; Kenneth Parkes, tween the northern Ecuadorian birds and/or Carnegie Museum of Natural History; Scott hybridization between those siskins and C. Lanyon and David Willard, Field Museum of Natural History. magellanica. Based on plumage morphology and distribution we surmise that the northern Ecua- REFERENCES dorian populations and Colombian nigricauda are more closely related to each other than either Chapman, F.M. 1912. Diagnoses of apparently new Colombian birds. Bull. Am. Mus. Nat. Hist. 31: is to nominate spinescens. 139-166. At Cerro Mongus this siskin was found to Fjeldsa,J., & N. Krabbe. 1990. Birds of the high Andes. be fairly common in the Espeletia-dominated Copenhagen. páramo (above 3400m) and in agricultural clear- Hilty, S.L., & W.L. Brown. 1986. A guide to birds of ings at 3300 m. In the páramo it was found only Colombia. Princeton. in monospecific flocks comprised of both sexes. Howell, T.R. 1968. Carduelinae (New World). Pp. 207-306. In R.A. Paynter, Jr. (ed.), Check-list of The largest flock in the páramo numbered 26 in- birds of the world, Vol. 14. Cambridge, Mass. dividuals. At our 3300 m camp, it was most fre- Krabbe, N. 1992. Notes on distribution and natural quently observed in association with Carduelis history of some poorly known Ecuadorian birds.