BirdLife species factsheet for Grey-tailed Piha
Grey-tailed Piha (Snowornis subalaris) has a localised distribution along the eastern slopes of the Andes, ranging from southern Colombia, through Ecuador to southern Peru. It inhabits humid forest at 500-1,400 m elevation (Snow 2020). The population size has not been quantified, but the species is described as uncommon (Stotz et al. 1996). The only threat known to the species is the loss and fragmentation of its habitat.
Grey-tailed Piha is currently listed as Near Threatened, approaching the threshold for listing as threatened under Criterion A3c. New information regarding the population trend suggests that the species may warrant a change in Red List status. Therefore, it will be re-assessed against all criteria:
Criterion A – The population trend has not been estimated directly. Tracewski et al. (2016) measured the forest loss within this species’s range between 2000 and 2012 as c. 535 km2. This roughly equates to a rate of forest loss of 4% over three generations (15 years; Bird et al. 2020) for this species, with the assumption that habitat loss has continued at the same rate to the present day.Population declines may additionally be exacerbated by habitat degradation and thus exceed the rate of forest cover change alone. Even though Grey-tailed Piha seems to be strictly forest-dependent (Snow 2020), it is however highly unlikely that the rate of population decline approaches the threshold for Vulnerable. The species’s listing as Near Threatened under C1 at the national level in Ecuador (Freile et al. 2018) supports this assumption, as it indicates that the rate of decline approaches, but does not exceed, 10% over three generations. Therefore, Grey-tailed Piha may be listed as Least Concern under this criterion.
Criterion B – The Extent of Occurrence (EOO) for this species is 630,000 km2. The maximum AOO (Area of Occupancy), as calculated by the area covered by forest within the range, is 16,000 km2. These values do not meet the threshold for Vulnerable (EOO < 20,000 km2, AOO < 2,000 km2). Therefore, Grey-tailed Piha may be listed as Least Concern under Criterion B.
Criterion C – The population size of Grey-tailed Piha has not been estimated. The national estimate for Ecuador is larger than 10,000 mature individuals (Freile et al. 2018), indicating that the global population is substantially larger than this number. Therefore, Grey-tailed Piha may be listed as Least Concern under Criterion C.
Criterion D – The population size is too large to approach the threshold for Vulnerable (1,000 mature individuals). Therefore, Grey-tailed Piha may be listed as Least Concern under Criterion D.
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 Grey-tailed Piha (Snowornis subalaris) be listed as Least Concern. We welcome any comments on the proposed listing.
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.
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*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).
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.
Freile, J. F.; Santander, T.; Carrasco, L. ; Cisneros-Heredia, D. F.; Guevara, E. A.; Sánchez-Nivicela, M.; Tinoco, B. A. 2018. Lista roja de las aves del Ecuador continental. Ministerio del Ambiente, Aves y Conservación, Comité Ecuatoriano de Registros Ornitológicos, Universidad del Azuay, Red Aves Ecuador, Universidad San Francisco de Quito. Quito, Ecuador.
Snow, D. 2020. Grey-tailed Piha (Snowornis subalaris). 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, Spain. https://www.hbw.com/node/57020 (Accessed 6 February 2020).
Stotz, D. F.; Fitzpatrick, J. W.; Parker, T. A.; Moskovits, D. K. 1996. Neotropical birds: ecology and conservation. University of Chicago Press, Chicago.
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.