Proposal (539) to South American Classification Committee

 

 

Elevate Sicalis olivascens mendozae to species status

 

The Sicalis yellow-finches are extremely confusing in the field AND in museums. Identification errors abound, and their taxonomy is hence contentious. Based on the examination of 107 recordings of species of Andean Sicalis (including 35 individuals of olivascens and 22 of mendozae) and on the study of over 200 Sicalis specimens (39 of S. o. olivascens and 30 of mendozae measured) and field studies of vocalizations, habitat use, distribution, behavior, and playback trials, Areta et al. (2012) proposed that Sicalis olivascens mendozae be treated as S. mendozae. Comments on the convoluted taxonomy of this taxon and photographs of olivascens and mendozae plus spectrograms of these and other related taxa were also published. Here we reproduce the abstract and several excerpts from the manuscript to demonstrate different aspects of critical differences between the taxa.

 

“Abstract. The poorly known Pseudochloris mendozae Sharpe, 1888, has usually been considered a subspecies of the widespread Greenish Yellow-Finch (Sicalis olivascens) of the Andes of Peru, Bolivia, northern Chile, and northwest Argentina. In this work, we present data on morphology, vocalizations, ecology, and distribution supporting the recognition of the Monte Yellow-Finch (Sicalis mendozae) (Sharpe 1888) as a full species. S. mendozae is 10% smaller in size (with no overlap in wing or bill measurements), and its average weight is 80% that of S. olivascens. In comparison with S. olivascens, breeding males of S. mendozae are considerably brighter, lack any olive tinge on the throat and breast, lack any dorsal mottling or streaking, and have a brighter olive rump. In fresh plumage nonbreeding males are similar to four other Sicalis species, differing subtly. Female S. mendozae is closest in appearance to the allopatric Patagonian Yellow-Finch (S. lebruni), differing chiefly by its olive rump. The song, complex song, and calls of S. mendozae are diagnostic, though it also imitates some other birds. S. mendozae is endemic to the arid Monte Desert of western Argentina from western Tucumán south to Mendoza, and is parapatric with S. olivascens of high Andean steppes. Contrary to literature reports, S. mendozae is nonmigratory but may move altitudinally, descending to lower altitudes during winter. We propose the recognition of the Monte Desert as a new Endemic Bird Area, based on the overlap of the geographic ranges of several bird species.”

 

“The pattern and quality of songs of male S. olivascens chloris from Putre, extreme northern Chile, and of male S. o. olivascens at the Cuesta de Randolfo, Catamarca, Argentina, more than 1000 km apart in a straight line, are strikingly similar. In contrast, the voices of S. olivascens from Cuesta de Randolfo and S. mendozae from Hualfín, just ~50 km apart in Catamarca province, differ radically. Hence, despite wide opportunity for significant geographic variation in voice, we found conservatism over a large geographic area in S. olivascens and an abrupt appearance of S. mendozae vocalizations. The sounds of S. mendozae remain diagnosable along the ~900 km that separate Hualfín from Cajón del Atuel (Mendoza, Argentina)” (pp. 662)

 

“We performed five playback experiments on S. olivascens with voices of S. olivascens and S. mendozae in Putre, extreme northern Chile (November 2011) and five on S. mendozae with voices of S. mendozae and S. olivascens in Parque Nacional Sierra de las Quijadas (November 2010)” (p. 655). “In all reciprocal playback experiments on S. olivascens and S. mendozae, males responded aggressively to conspecific vocalizations, approaching the sound’s source and singing, while ignoring heterospecific vocalizations, regardless of the order of playback. Additionally, two different males of S. mendozae recorded at Cajón del Atuel on 29 December 2007 answered to playback of their own voices by approaching the sound source but quit vocalizing and remained silent, perched on boulders. One of them flew more than 80 m across a deep canyon to approach its own vocalization, but both birds ignored the voices of S. olivascens, S. lebruni, and S. uropygialis of Straneck (1990a,b), which we used in playback trials. Likewise, two different wintering groups of S. lebruni found in what appeared to be good habitat for S. mendozae in Paso Córdoba (May 2011, Río Negro province, Argentina) ignored songs and calls of S. mendozae and responded strongly to calls of S. lebruni from Santa Cruz province, approaching the sounds’ source and uttering very similar calls” (pp. 662 and 664)

 

“Judged from plumage and structural features, S. mendozae appears to be more closely allied to S. lutea or S. lebruni than to S. olivascens. The staccato voice of S. mendozae resembles the song of S. lebruni and may provide some evidence for their relationship, whereas S. lutea is not obviously sexual dimorphic like S. mendozae, undermining the idea of a close relationship between them. However, since we lack a comparative phylogenetic study to assess the value of plumage as a phylogenetically informative character in Sicalis, the precise relationships within Sicalis await further analyses. Until that moment, we consider S. mendozae and S. lebruni to be sister species, and recommend placing S. mendozae between S. olivascens and S. lebruni in the linear sequence.” (p. 666)

 

Recommendation: we recommend a YES vote to recognize Sicalis mendozae as a full species.

 

Literature cited:

 

Areta, J.I., Pearman, M. & R. Ábalos. 2012. Taxonomy and biogeography of the Monte Yellow-Finch (Sicalis mendozae): understanding the endemic avifauna of Argentina’s Monte Desert. Condor 114: 654-671.

 

Nacho Areta, Mark Pearman, and Raúl Abalos, August 2012

 

 

Comments from Stiles:  “YES, a good case made for splitting it, clearly places the burden of proof on those who would consider mendozae a subspecies of olivascens.”

 

Comments from Robbins:  “YES.  Both vocal and plumage data support treating Sicalis [olivascens] mendozae as a species.”

 

Comments from Pacheco: “YES.  Em vista dos resultados apresentados em Areta et al. 2012, considero coerente o tratamento de espécie plena para S. mendozae.”

 

Comments from Pérez-Emán: “YES. Information provided by Areta et al (2012) on morphology, vocalizations, habitat, and distribution provides enough support for this split.”

 

Comments from Jaramillo: “YES. Having had the opportunity to see mendozae in the last couple of years, they are indeed distinct in all manners (ecologically, vocally, and visually) from olivascens. Indeed, Patagonian Sierra-Finch is what they remind me of, and I would go along with them being sisters. I have heard a good deal of variation in song in olivascens on the Chilean side, but they never approach mendozae from what I have heard.”

 

Comments from Nores: “YES.  Vocal data and playback experiments suggest treating Sicalis mendozae as a species. However, as this is a taxonomically difficult group, I hope to see a molecular analysis separating the two species, to convince me definitely. In addition, the parapatric distribution of the species suggests subspecies instead of species.”