BirdLife species factsheet for Gold-ringed Tanager
Gold-ringed Tanager (Bangsia aureocincta) is endemic to Colombia, where it occurs in a small area on the Pacific slope of the West Andes. The species occupies humid and mossy cloud forests at 350-2,195 m (Renjifo et al. 2014). The population size is preliminarily placed in the band 600-1,700 mature individuals, though this may be an underestimate.
The species is threatened by the loss of its habitat. Deforestation in parts of the range has been severe in the past, but has slowed down considerably in more recent years or even reversed, with areas being reforested (Renjifo et al. 2014, Tracewski et al. 2016, Global Forest Watch 2020). Nevertheless, models of future habitat availability in the Andes of Colombia and Ecuador project 24% habitat loss by the end of the century in the altitudinal band of Gold-ringed Tanager (Renjifo et al. 2014).
Gold-ringed Tanager is currently listed as Endangered under Criterion B2ab(i,ii,iii,v) (BirdLife International 2020). However, reviewing available information regarding the distribution range and population size suggests that the species may warrant a change in Red List status (see also Renjifo et al. 2014). Therefore, it will be re-assessed against all criteria:
Criterion A – The population trend has not been estimated directly. The only threat known to the species is the loss of its habitat; yet forest loss within the range has been very low over the past ten years (< 2%; Tracewski et al. 2016, Global Forest Watch 2020; one generation length being 3.3 years; Bird et al. 2020)*. However, models revealed that available habitat in the species’s altitudinal range will decrease by c. 24% across Ecuador and Colombia by the end of this century (Renjifo et al. 2014). Therefore, the species is tentatively suspected to be in a slow decline, the rate of which does not exceed 10% over ten years. Gold-ringed Tanager therefore qualifies as Least Concern under Criterion A.
Criterion B – The Extent of Occurrence (EOO) for this species is 8,000 km2. The maximum Area of Occupancy (AOO), as calculated by a 4 km2 grid over the area of mapped range, is 1,940 km2. These values meet the threshold for Vulnerable under Criterion B. However, in order to be listed under this criterion, at least two further conditions have to be met.
Observational records of the species are fairly continuous throughout the range (eBird 2020), and therefore the species is not severely fragmented sensu ICUN (see IUCN Standards and Petitions Committee 2019). The only threat known to the species is habitat loss. However, the effects of the very low rates of deforestation and the slow contraction in available habitat projected over the next decades are unlikely to have impacts that are severe enough to extirpate large parts of the population within the next ten years. Therefore, the species cannot be considered to occur at ≤10 locations**. Considering the small range, we can precautionarily assume that the number of locations** is slightly above 10, so that the species approaches the threshold for listing as threatened under subcriterion a. Habitat availability is projected to decline slowly until the end of the century (Renjifo et al. 2014), and subcriterion b(ii,iii) is met. The species is not known to undergo extreme fluctuations, and thus subcriterion c is not met. Overall, even though the EOO and AOO are small, Gold-ringed Tanager does not meet enough conditions to qualify as threatened under Criterion B. The species may therefore be considered Near Threatened, approaching the threshold for listing as threatened under Criterion B1ab(ii,iii)+2ab(ii,iii).
Criterion C – The population size of Gold-ringed Tanager is thought to number 600-1,700 mature individuals. This meets the threshold for listing as threatened under Criterion C. However, to do so a species must meet further conditions.
It is suspected that the species is undergoing a slow population decline due to habitat loss. A suspected decline, however, precludes a listing as threatened under Criterion C. Even though we have no direct information on the subpopulation structure, given the even spread of records throughout the range (eBird 2020) we can tentatively assume that the species forms just one subpopulation. Overall, Gold-ringed Tanager only meets two out of three conditions and can therefore not be listed as threatened under Criterion C. Nevertheless, it may be listed as Near Threatened, approaching the threshold for listing as threatened under Criterion C2a(ii).
Criterion D – The population size is preliminarily placed in the band 600-1,700 mature individuals. Assuming that the true population size is closer to the lower end of the estimate, Gold-ringed Tanager may be listed as Vulnerable under Criterion D1.
Criterion E – To the best of our knowledge no quantitative analysis of extinction risk has been conducted for this species. Therefore, it cannot be assessed against this criterion.
Therefore, it is suggested that Gold-ringed Tanager (Bangsia aureocincta) be listed as Vulnerable under Criterion D1. We welcome any comments on the proposed listing and specifically request up-to-date information regarding the population size.
Please note that this topic is not designed to be a general discussion about the ecology of the species, rather a discussion of its Red List status. Therefore, please make sure your comments are relevant to the discussion outlined in the topic. By submitting a comment, you confirm that you agree to the Comment Policy.
*Bird generation lengths are estimated using the methodology of Bird et al. (2020), as applied to parameter values updated for use in each IUCN Red List for birds reassessment cycle. Values used for the current assessment are available on request. We encourage people to contact us with additional or improved values for the following parameters; adult survival (true survival accounting for dispersal derived from an apparently stable population); mean age at first breeding; and maximum longevity (i.e. the biological maximum, hence values from captive individuals are acceptable).
**The term ‘location’ refers to a distinct area in which a single threatening event can rapidly affect all individuals of the taxon present, with the size of the location depending on the area covered by the threatening event. Where a taxon is affected by more than one threatening event, location should be defined by considering the most serious plausible threat (IUCN 2001, 2012).
An information booklet on the Red List Categories and Criteria can be downloaded here and the Red List Criteria Summary Sheet can be downloaded here. Detailed guidance on IUCN Red List terms and definitions and the application of the Red List Categories and Criteria can be downloaded here.
Bird, J. P.; Martin, R.; Akçakaya, H. R.; Gilroy, J.; Burfield, I. J.; Garnett, S.; Symes, A.; Taylor, J.; Šekercioğlu, Ç.; Butchart, S. H. M. (2020). Generation lengths of the world’s birds and their implications for extinction risk. Conservation Biology online first view.
BirdLife International. 2020. Species factsheet: Bangsia aureocincta. http://www.birdlife.org (Accessed 03 April 2020).
eBird. 2020. eBird: An online database of bird distribution and abundance [web application]. eBird, Ithaca, New York. http://www.ebird.org (Accessed 03 April 2020).
Global Forest Watch. 2020. Interactive Forest Change Mapping Tool. http://www.globalforestwatch.org (Accessed 03 April 2020).
IUCN. 2001. IUCN Red List Categories and Criteria: Version 3.1. IUCN Species Survival Commission. IUCN, Gland, Switzerland and Cambridge, U.K.
IUCN. 2012. IUCN Red List Categories and Criteria: Version 3.1. Second edition. IUCN Species Survival Commission. IUCN, Gland, Switzerland and Cambridge, U.K. www.iucnredlist.org/technical-documents/categories-and-criteria.
IUCN Standards and Petitions Committee. 2019. Guidelines for using the IUCN Red List Categoreis and Criteria. Version 14. http://www.iucnredlist.org/documents/RedListGuidelines.pdf.
Renjifo, L. M.; Gomez, M. F.; Velasquez-Tibata, J.; Amaya-Villarreal, A. M.; Kattan, G. H.; Amaya-Espinel, J. D.; Burbano-Giron, J. 2014. Libro rojo de aves de Colombia, Volumen I: bosques humedos de los Andes y la costa Pacifica. Editorial Pontificia Universidad Javeriana e Instituto Alexander von Humboldt. Bogota D.C., Colombia.
Tracewski, Ł.; Butchart, S. H. M.; Di Marco, M.; Ficetola, G. F.; Rondinini, C.; Symes, A.; Wheatley, H.; Beresford, A. E.; Buchanan, G. M. 2016. Toward quantification of the impact of 21st-century deforestation on the extinction risk of terrestrial vertebrates. Conservation Biology 30: 1070-1079.