Bogota Rail (Rallus semiplumbeus): Revise global status?

This discussion was first published as part of the 2020 Red List update. At the time, a decision regarding the status of this species was pended and the post remained open. Following experts’ comments on the status review, the topic has now been updated to reflect the most recent information. The initial topic on this analysis can be found here.

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1 Response to Bogota Rail (Rallus semiplumbeus): Revise global status?

  1. As I commented last year when the status of the species was being revised, the lack of high-quality data on its ecology and demography makes it a truly tricky case for evaluation. Data in Annex I left me with the same feeling as last year: there are some conclusions regarding the species’ population dynamics that are dangerously based on speculation. In cases like this, I always recommend to take a more conservative stance and avoid changing current statuses unless data clearly and confidently supports it. A good example for this is the assumption that effective dispersal is taking place between localities and hence that ~95% of the population may act as a single subpopulation (this is taken from Renjifo et al. 2016). Aside from expert opinions and feelings on the matter, there is no rigorous information that could support such claim.

    In any case, based on the–still scarce–information available for this species and Annex 1 and 2, it seems Bogotá Rail no longer qualifies as EN for criteria B1, B2 and C2. I, however, still have some doubts on the evaluation of criterion B2. Information on Annex 1 indicates that the species’ AOO is ~504 km2 and that its populations possibly occur in 6-10 localities. This seems to me as an overestimation and it would be nice to have more clarity on how this was calculated. Renjifo et al. (2016) estimated that remaining habitat for this species is ~164.6 km2, thus it does not seems likely that its AOO actually exceeds the EN threshold. Also, taking into consideration that several localities where the species has been recorded are close to one another and spatially clustered (see Renjifo et al. 2016, Roselli et al. 2016), I wonder whether some of those areas might truly represent separate localities.

    Summary: evaluation of criterion B2 seems a bit shaky. Current information suggest that the species’ AOO is much more restricted than information in Annex 1 suggests. The fact that the species occurs in more than 5 locations should also be revised. From my point of view, the species could still be listed as EN according to criterion B2, as Renjifo et al. (2016) have suggested.

    Note: population declines have been inferred for Bogotá Rail based on anecdotal information for a long time, but a recent analysis based on a 26-year dataset indeed suggest that, at least in the Bogotá savanna, the species is–slowly–declining (see Stiles et al. 2021).

    References:
    ** Renjifo, L. M., A. M. Amaya-Villarreal, J. Burbano-Girón, and J. Velásquez-Tibatá (Editors) (2016). Libro rojo de las aves de Colombia vol. II: especies acuáticas de ecosistemas abiertos y secos, tierras altas del Darién, Sierra Nevada de Santa Marta e insulares. Editorial Pontificia Universidad Javeriana, and Instituto de investigación de Recursos Biológicos Alexander von Humboldt, Bogotá, Colombia.
    ** Roselli, L., A. Morales-Rozo, and J. Amaya-Espinel (2016). Rallys semiplumbeus. In Libro rojo de las aves de Colombia vol. II: especies acuáticas de ecosistemas abiertos y secos, tierras altas del Darién, Sierra Nevada de Santa Marta e insulares (L. M. Renjifo, A. M. Amaya-Villarreal, J. Burbano-Girón, and J. Velásquez-Tibatá, Editors). Editorial Pontificia Universidad Javeriana, and Instituto de investigación de Recursos Biológicos Alexander von Humboldt, Bogotá, Colombia.
    ** Stiles, F. G., L. Roselli, and S. De La Zerda (2021). Una avifauna en cambio: 26 años de conteos navideños en la Sabana de Bogotá, Colombia. Ornitología Colombiana 19: 1–65.

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