Archived 2014 discussion: Bearded Helmetcrest (Oxypogon guerinii) is being split: list both O. cyanolaemus and O. stuebelii as Vulnerable and both O. guerinii and O. lindenii as Near Threatened?

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.

Bearded Helmetcrest Oxypogon guerinii is being split into O. guerinii, O. cyanolaemus, O. lindenii and O. stuebelii, following the application of criteria set out by Tobias et al. (2010).

Prior to this taxonomic change, O. guerinii (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 criteria.

O. guerinii (as defined following the taxonomic change) occurs in the east Andes of Colombia, south to Cundinamarca. The global population size has not been quantified, but this species is described as locally common, probably at around 3,200-5,200 m, in high mossy páramo where Espeletia species are present (Hilty and Brown 1986, McMullan et al. 2010).

O. cyanolaemus occurs in Santa Marta, north-eastern Colombia, where it is locally common in páramo and adjacent shrubby mountain valleys, probably at around 3,200-5,200 m (Hilty and Brown 1986, McMullan et al. 2010).

O. lindenii occurs in the Andes of north-western Venezuela, in Merida and Trujillo, at 3,600-4,500 m. It is seasonally very common in open páramo, being especially numerous during the rainy season when breeding; at other times of the year it descends to the páramo-forest ecotone near the treeline, with very few remaining in high páramo during the dry months (Hilty 2003).

O. stuebelii occurs in Nevado del Ruiz, central Colombia, where it is locally common, probably at around 3,200-5,200 m, in high mossy páramo where Espeletia species are present (Hilty and Brown 1986, McMullan et al. 2010).

All of these species are inferred to be in decline owing to on-going habitat destruction and degradation caused by over-grazing (del Hoyo et al. 1999), as well as the alteration of páramo caused by burning and the expansion of agriculture and scrubland (WWF 2001).

Both O. cyanolaemus and O. stuebelii could qualify as Vulnerable (or perhaps Endangered) under criterion B1ab(ii,iii,v), if it is shown that they are known to occur at fewer than 11 locations (or their habitat is severely fragmented, i.e. over 50% in patches too small to support viable populations), as they occupy very small ranges (with Extents of Occurrence [EOOs] estimated at c.2,800 km2 and c.4,000 km2 respectively), with on-going declines taking place in the area and quality of suitable habitat.

Both O. guerinii and O. lindenii could qualify as Near Threatened (or perhaps Vulnerable) under criterion B1ab(ii,iii,v), if they are shown to occur at fewer than 20 locations or their habitat is considered at least very fragmented (approaching 50% in patches too small to support viable populations), as they occupy  small ranges (with EOOs estimated at c.19,700 km2 and c. 8,600 km2 respectively), in which suitable habitat is in decline and being degraded.

Comments are invited on these suggested categories and further information is requested. In addition to the questions raised above, information is also sought on these species’ likely population sizes (number of mature individuals) and likely subpopulation structure (number of mature individuals in the largest subpopulation or percentage of all mature individuals in a single subpopulation), where subpopulations are defined as geographically or otherwise distinct groups in the population between which there is little demographic or genetic exchange (typically one successful migrant individual per year or less).

References:

del Hoyo, J., Elliott, A. and Sargatal, J. (1999) Handbook of the Birds of the World, vol. 5: Barn-owls to Hummingbirds. Barcelona, Spain: Lynx Edicions.

Hilty, S. L. (2003) Birds of Venezuela. London, UK: A & C Black.

Hilty, S. L. and Brown, W. L. (1986) A guide to the birds of Colombia. Princeton, NJ: Princeton University Press.

McMullan, M., Donegan, T. M. and Quevedo, A. (2010) Field Guide to the Birds of Colombia. Bogotá, Colombia: Fundación ProAves de Colombia.

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.

World Wildlife Fund (2001). Santa Marta páramo (NT1007). [online] Available at: http://web.archive.org/web/20061007183352/http://worldwildlife.org/wildworld/profiles/terrestrial/nt/nt1007_full.html [Accessed 28 September 2012]

Related posts:

  1. Archived 2014 discussion: Moluccan Scops-owl (Otus magicus) is being split: list O. tempestatis as Vulnerable?
  2. Archived 2011-2012 topics: Dull-mantled Antbird (Myrmeciza laemosticta) and Magdalena Antbird (M. palliata): newly split and threatened?
  3. Archived 2010-2011 topics: Black-backed Thornbill (Ramphomicron dorsale) and Santa Marta Wren (Troglodytes monticola): uplist both to Endangered?
  4. Archived 2011-2012 topics: Brown-banded Antpitta (Grallaria milleri): downlist to Vulnerable?
  5. Archived 2010-2011 topics: Paramo Tapaculo (Scytalopus opacus) and Paramillo Tapaculo (S. canus) have been split: list as Least Concern and Endangered respectively?
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5 Responses to Archived 2014 discussion: Bearded Helmetcrest (Oxypogon guerinii) is being split: list both O. cyanolaemus and O. stuebelii as Vulnerable and both O. guerinii and O. lindenii as Near Threatened?

  1. O. guerinii .Despite being restricted to a few paramos in eastern andes in Colombia, this species has a relatively large range (Paramo de Chingaza, Sumapaz, Pisba, Cocuy, La Rusia, Paramo de Santurban, Vijagual ) and hence does not approach the thresholds for Vulnerable under the range size criteria (B and D2: of less than 20,000 km2, combined with a declining or fluctuating range size, habitat extent/quality or population size, and a small number of locations or severe fragmentation).
    Therefore, the only relevant criterion is A, which relates to reductions in population size. Until recently, the population was thought to be declining slowly, but not sufficiently rapidly to approach the threshold for listing as Vulnerable under criterion A (at least a 30% decline over ten years or three generations, whichever is longer).

  2. O. cyanolaemus . A lack of data on key sites combined with the absence of long-term regular monitoring populations (in Santa Marta) means that it is difficult to determine a global population trend for the species.

  3. Andy Symes says:

    According to Collar and Salaman (2013) there are in fact no confirmed records of O. cyanolaemus since 1946; the authors recommend classification as Critically Endangerered.

    O. stuebelii is considered to be under relatively little threat within its small range and is recommended as Vulnerable under criterion D1.

    Full details here:
    Collar, N.J. & Salaman, P. 2013. The taxonomic and conservation status of the Oxypogon helmetcrests. Conservación Colombiana 19: 31-38.
    http://www.proaves.org/wp-content/uploads/2013/12/The-taxonomic-and-conservation-status-of-the-Oxypogon-helmetcrests.pdf

  4. 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:

    O. guerinii as Least Concern

    O. cyanolaemus as Critically Endangered under criterion C2a(ii)

    O. lindenii as Least Concern

    O. stuebelii as Vulnerable under criterion D

    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.

  5. 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.