Proposal (770) to South American Classification Committee
Treat Megascops colombianus as a subspecies of M. ingens
Effect on AOU SACC classification: Megascops colombianus would return to former status as a subspecies of M. ingens.
Background: From the SACC footnote under the name M. colombianus:
Megascops columbianus was formerly (e.g., Meyer de Schauensee 1970) considered a subspecies of M. ingens, but see Fitzpatrick & O'Neill (1986) for recognition as a separate species; this treatment was followed by Marks et al. (1999), but not Ridgely & Greenfield (2001). They form a superspecies. Proposal needed for continued recognition of this species.
Fitzpatrick and O’Neill (1986) argued that morphological differences (wing length, tarsus length, and amount of unfeathered tarsus) were sufficient to consider M. colombianus a species apart from M. ingens. Furthermore, they suggested that M. colombianus was sister to their newly described M. petersoni. As mentioned in the above note, some more recent authors have reverted to the original taxonomy, returning colombianus to M. ingens.
New information: Dantas et al. (2016) provided a phylogenetic hypothesis that showed that the sister relationship proposed by Fitzpatrick and O’Neill (1986) was incorrect, and that M. ingens and colombianus were indeed sisters, and not in the same clade as M. petersoni. Furthermore, Krabbe (2017) showed, through vocal analysis, that there were no strong differences in voice between ingens and colombianus. He concluded:
there do not appear to be vocal differences between M. [ingens] colombianus and M.
i. ingens. Differences between them in size, general hue, tail/tarsus
proportions and tarsal feathering (Fitzpatrick & O’Neill 1986) leave little
doubt as to the validity of the taxon colombianus,
but vocally there is no support for ranking it as a species.”
Analysis and recommendation: I am strongly convinced that Krabbe’s recommendation is the correct one. I recommend a YES vote to returning colombianus to M. ingens.
Dantas, S. M., J. D. Weckstein, J. M. Bates, N. K. Krabbe, C. D. Cadena, M. B. Robbins, E. Valderrama, and A. Aleixo. 2016. Molecular systematics of the new world screech-owls (Megascops: Aves, Strigidae): biogeographic and taxonomic implications. Molecular Phylogenetics and Evolution 94:626-634.
Fitzpatrick, J. W., and J. P. O’Neill. 1986. Otus petersoni, a new screech-owl from the eastern Andes, with systematic notes on O. colombianus and O. ingens. Wilson Bulletin 98: l-14.
Comments from Stiles: "YES. New genetic evidence and vocal similarity (to which I can attest, having heard both) support subspecies status for columbianus."
Comments from Robbins: "YES. Given that genetic data indicate that Megascops colombianus is sister to M. ingens, and vocal analyses by Niels Krabbe demonstrated that they are very similar, it seems best to treat colombianus as a subspecies of ingens."
Comments from Zimmer: “YES. I’m convinced that vocal similarities/differences are the keys to species-limits in screech-owls, trumping any apparent morphological similarities/differences until and unless genetic data tell us otherwise. In this case, recent genetic analysis supports the vocal analysis of Krabbe, so treating colombianus as a subspecies of ingens seems to be the way to go.”
Comments from Remsen: “YES. Genetic and vocal data strongly indicate subspecies rank for this taxon.”
Comments from Stotz: “YES. Lack of vocal distinctiveness makes it clear that colombianus should be lumped back into ingens.”
Comments from Jaramillo: “YES due to data on voice and genetics.”
Comments from Claramunt: “NO. If it is true that they are different in “size, general hue, tail/tarsus proportions and tarsal feathering”, whether they are similar or different in vocalizations is immaterial. They seem to be two different birds. Vocalizations do not trump every other piece of evidence, in my opinion.”
Comments from Pacheco: “YES. The data presented here are sufficient to comply with the recommendation of this proposal.”