Archived 2016 topics: Northern Barred Woodcreeper (Dendrocolaptes sanctithomae) is being split: request for information on D. punctipectus.

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

Lynx Edicions and BirdLife International will soon publish the second volume of 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 2 of the checklist (for passerines) will begin to be incorporated into the 2016 Red List update, with the remainder 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.

Northern Barred Woodcreeper Dendrocolaptes sanctithomae is being split into D. sanctithomae and D. punctipectus, following the application of criteria set out by Tobias et al. (2010).

Prior to this taxonomic change, D. sanctithomae was listed as Least Concern, on the basis that it did not approach the threshold for Vulnerable under any criterion. D. sanctithomae (as now defined following the taxonomic change) is found in lowland and foothill forest (up to 1,800m) from southern Mexico south to northern and western Colombia and north Ecuador (Marantz et al. 2016). It is uncommon to fairly common, but it has probably been affected by deforestation within its range. However, these declines are not suspected to be >30%, and its global population size is thought to be above 10,000 mature individuals (Partners in Flight estimated the pre-split species total population at 50,000-499,999 individuals [A. Panjabi in litt. 2008]). Therefore, it is not thought to approach the threshold for Vulnerable under any criterion, and so would warrant listing as Least Concern.

D. punctipectus is found in lowland forest in northern Colombia (from the middle of the Magdalena Valley south to Santander, and also Norte de Santander) and north-western Venezuela (from the Maracaibo Basin in Zulia and northern Mérida) (Marantz et al. 2016). Its population is inferred to be declining as a result of extensive deforestation within its range (Marantz et al. 2016), but it is unsure whether declines may be at a rate of >30% within the past 3 generations (c.11.5 years). The population size has not directly been quantified but the pre-split species appears to have been very rarely recorded within this newly defined species’s range (see ebird webpage: http://ebird.org/content/ebird/). This suggests that the population size of this species may in fact be quite small despite an apparently fairly large range. We request any information regarding potential population size estimates for this species, and any evidence to suggest that the population size is <10,000 mature individuals and in continuing decline may mean this species warrants listing as Vulnerable under criterion C2a(i) or C2a(ii) depending on the likely subpopulation structure.

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

 

References:

Marantz, C.A., Aleixo, A., Bevier, L.R. and Patten, M.A. (2016). Northern Barred Woodcreeper (Dendrocolaptes sanctithomae). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/56613 on 30 September 2016).

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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2 Responses to Archived 2016 topics: Northern Barred Woodcreeper (Dendrocolaptes sanctithomae) is being split: request for information on D. punctipectus.

  1. Chris Sharpe says:

    I wholeheartedly agree that taxon punctipectus deserves some degree of threat status. The La Maracaibo Basin was identified as a conservation priority decades ago, perhaps the only ecoregion that had been almost entirely transformed in a country that had low (less than 1%) deforestation rates and an exemplary environmental record. Already by the 1990s, 90% of the lowland forest in the Sur del Lago region had been entirely lost and most of the rest was degraded. Of the 60,000 km2 lost in Venezuela in the four decades up to 1993, half of this corresponds to the W Llanos and S & W of Lake Maracaibo (i.e. the latter this taxon’s range), based on satellite data interpreted by Catalán for the then MARNR (I no longer have his report, but these data are cited in the Venezuela section of IUCN’s 1996 Conservation Atlas of Tropical Forests: the Americas). My appreciation from visits to Perijá and the Mérida Andes is that since then foothill forests have been steadily deforested with the arrival over the past 20 years of large numbers conuco farmers as well as expansion of pastureland. I am sure that there are modern analyses of forest cover change. There can be very few modern records of this bird in Venezuela, and unless the situation is better in Colombia, this taxon is likely in quite a precarious state due to large-scale historical habitat loss. There are no population estimates.

  2. James Westrip (BirdLife) says:

    Based on available information, our preliminary proposal for the 2016 Red List would be to list:

    D. sanctithomae as Least Concern.

    D. punctipectus as Vulnerable under criterion C2a(i).

    There is now a period for further comments until the final deadline of 28 October, after which the recommended categorisations will be put forward to IUCN.

    Please note that we will then only post final recommended categorisations on forum discussions where these differ from the initial proposal.

    The final 2016 Red List categories will be published on the BirdLife and IUCN websites in early December, following further checking of information relevant to the assessments by both BirdLife and IUCN.

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