Archived 2014 discussion: Silvery Grebe (Podiceps occipitalis) is being split: list P. juninensis as Near Threatened or Vulnerable?

This is part of a consultation on the Red List implications of extensive changes to BirdLife’s taxonomy for non-passerines

Lynx Edicions and BirdLife International will soon publish the HBW-BirdLife Illustrated Checklist of the Birds of the World, building off the Handbook of the Birds of the World series, and BirdLife’s annually updated taxonomic checklist.

The new Checklist will be based on the application of criteria for recognising species limits described by Tobias et al. (2010). Full details of the specific scores and the basis of these for each new taxonomic revision will be provided in the Checklist.

Following publication, an open and transparent mechanism will be established to allow people to comment on the taxonomic revisions or suggest new ones, and provide new information of relevance in order to inform regular updates. We are also actively seeking input via a discussion topic here regarding some potential taxonomic revisions that currently lack sufficient information.

The new Checklist will form the taxonomic basis of BirdLife’s assessments of the status of the world’s birds for the IUCN Red List. The taxonomic changes that will appear in volume 1 of the checklist (for non-passerines) will begin to be incorporated into the 2014 Red List update, with the remainder, and those for passerines (which will appear in volume 2 of the checklist), to be incorporated into subsequent Red List updates.

Preliminary Red List assessments have been carried out for the newly split or lumped taxa. We are now requesting comments and feedback on these preliminary assessments.

Silvery Grebe Podiceps occipitalis is being split into P. occipitalis and P. juninensis, following the application of criteria set out by Tobias et al. (2010).

Prior to this taxonomic change, P. occipitalis (BirdLife species factsheet) was listed as being of Least Concern, on the basis that it was not thought to approach the thresholds for Vulnerable under any of the IUCN Red List criteria.

P. juninensis inhabits the Andean highland from Antofagasta (and occasionally Santiago) in northern Chile and Catamarca in north-western Argentina to Junín in Peru (casually descending to the coast of Peru), with a few breeding sites further north in Peru, Ecuador and the Cordillera Central of Colombia (Fjeldså 2004).

The species’s population is said to have become very localised north of the Bolivian-Peruvian Altiplano, and it may be vanishing from the páramos of northern Peru, Ecuador and Colombia (Fjeldså 2004). The population on Lake Mica in Ecuador appears to have declined markedly in recent years. Threatening processes include the modification, pollution and siltation of wetlands, as well as the potential impacts of introduced species (Fjeldså 2004). In Colombia, the species is in decline owing to habitat conversion and introduced species (Renjifo et al. 2002). Owing to these observed declines, juninensis has been regarded as threatened (Vulnerable) (Fjeldså 2004).

It is suggested that this species be listed as Near Threatened or Vulnerable under criteria A2ce;3ce;4ce, on the basis that it is suspected to be undergoing a population decline approaching or exceeding 30% over three generations (c.21 years).

P. occipitalis (as defined following the taxonomic change) is found from Tierra del Fuego up to the Pampas, and to Cordoba and Santa Fé in Argentina, migrating north to northern Argentina, southern Paraguay and extreme southern Bolivia, and also occurs in semi-arid central Chile, where it nests when water levels are high (Fjeldså 2004, Guyra Paraguay 2005, Tobias and Seddon 2007). It is thought likely to be listed as being of Least Concern, on the basis that it is not thought to approach the thresholds for Vulnerable under any of the IUCN Red List criteria.

Comments on these suggested categories are invited and further information would be welcomed.


Fjeldså, J. (2004) The Grebes. Oxford, UK: Oxford University Press.

Guyra Paraguay (2005) Atlas de las aves del Paraguay. Asunción, Paraguay: Asociación Guyra Paraguay.

Renjifo, L. M., Franco-Maya, A. M., Amaya-Espinel, J. D., Kattan, G. H. and López-Lanús, B. (Eds) (2002) Libro rojo de aves de Colombia. Bogatá, Colombia: Instituto Humboldt Colombia and Ministerio del Medio Ambiente.

Tobias, J. A. and Seddon, N. (2007) Ornithological notes from southern Bolivia. Bulletin of the British Ornithologists’ Club 127: 293–300.

Tobias, J. A., Seddon, N., Spottiswoode, C. N., Pilgrim, J. D., Fishpool, L. D. C. and Collar, N. J. (2010) Quantitative criteria for species delimitation. Ibis 152: 724–746.

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3 Responses to Archived 2014 discussion: Silvery Grebe (Podiceps occipitalis) is being split: list P. juninensis as Near Threatened or Vulnerable?

  1. Tatiana Santander G. says:

    The Silvery Grebe has undergone local extinction as well as colonization process over the last three decades in Ecuador. The species is no longer found below 3000 m a.s.l and has been extirpated from Yahuarcocha and San Pablo where was formerly present in the early 80s, in addition at Cuicocha the species has suffered a severe decline (~80%) over the last four decades. These figures indicate an overall decline in its northern distribution in the country. Currently over the 90% of the total country population relies on two wetlands: La Mica and Colta, this last one facing an accelerated sedimentation process which jeopardizes the fate of the wetland and the species on the mid-term. Population size is at La Mica is suspected to have been drastically reduced ever since a dam construction took place at the wetland in the early 90s, however population trend at this site trend has remained stable over 2004 – 2013 period. Colta is a recently colonized site, population at this site has experienced an extremely rapid growth over 2004 – 2013 period more likely related with immigration process. Despite current population trends does not exhibit negative patterns we recommend to regard the species as Endangered at the country level, particularly because of its small population size that according to our census data will not exceed the 1000 adult individuals (< 2500 individuals IUCN criteria). Information based on Guevara et al. in prep. The status of the Silvery Grebe (Podiceps occipitalis juninensis) in Ecuador: recent changes in distribution, population trends and conservation needs.

  2. Joe Taylor says:

    Preliminary proposals

    Based on available information and comments posted above, our preliminary proposals for the 2014 Red List would be to treat:

    P. occipitalis as Least Concern

    P. juninensis as Near Threatened under criteria A2ce+3ce+4ce

    There is now a period for further comments until the final deadline of 31 March, after which recommended categorisations will be put forward to IUCN.

    The final Red List categories will be published on the BirdLife and IUCN websites in mid-2014, following further checking of information relevant to the assessments by both BirdLife and IUCN.

  3. Andy Symes says:

    Recommended categorisations to be put forward to IUCN

    Following further review, there have been no changes to our preliminary proposals for the 2014 Red List status of these species.

    The final categorisations will be published later in 2014, following further checking of information relevant to the assessments by BirdLife and IUCN.

Comments are closed.