BirdLife species factsheet for Plumbeous Hawk
Plumbeous Hawk (Cryptoleucopteryx plumbea) occurs from eastern Panama through western Colombia and Ecuador to northwestern Peru. It inhabits closed-canopy humid forests at up to 800 m, but has also been recorded in degraded forest (Bierregaard 1994, P. Salaman in litt. 1999, Bierregaard et al. 2020). The species is described as uncommon (Stotz et al. 1996). The global population is tentatively placed in the band 10,000-19,999 mature individuals. This could however be an underestimate as the species is potentially underrecorded in remaining habitat (Bierregaard et al. 2020); moreover the population in Colombia is thought to slightly exceed 10,000 mature individuals (Renjifo et al. 2014).
The species is threatened by habitat loss. There has been widespread deforestation across most of its range, primarily driven by the expansion of agriculture, with other prominent drivers being logging for timber and mining activities (M. Sanchez in litt. 2013).
Plumbeous Hawk is currently listed as Vulnerable under Criterion A2c+3c+4c (BirdLife International 2020). However, new information regarding the population trend suggest that the species may warrant a change in Red List status. Therefore, the species will be re-assessed against all criteria:
Criterion A – Plumbeous Hawk is threatened by the loss of forests within the range. Rates of deforestation have however been low over the past three generations (17.4 years; Bird et al. 2020*), amounting to c. 4% over this period (Tracewski et al. 2016). It is however challenging to assess the possible effects on the population size: while the species’s tolerance of degraded habitats indicates that the population may not be severely impacted by habitat loss, its preference of forest interiors for hunting of prey suggests otherwise. Using a precautionary approach, we can tentatively assume that the rate of population decline is faster than the rate of forest loss, amounting to up to 10% over three generations. Plumbeous Hawk would therefore qualify as Least Concern under Criterion A.
Criterion B – The species’s range is too large to warrant listing as threatened under Criterion B1 (Extent of Occurrence = 656,000 km2) and thus Plumbeous Hawk qualifies as Least Concern under this criterion.
Criterion C – The global population is estimated at 10,000-19,999 mature individuals. Assuming that the true population size is closer to the lower end of the estimate, this approaches the threshold for listing as threatened under Criterion C. However, in order to be listed as Near Threatened under this criterion, further conditions have to be met.
The species is suspected to decline by up to 10% over three generations, but a suspected decline does not allow listing as threatened under sub-criterion 1. The subpopulation structure has not been investigated directly. All individuals in Colombia are assumed to belong to one subpopulation (Renjifo et al. 2014). This suggests that in the northern part of the range, there is one subpopulation ranging from eastern Panama through Colombia to northwestern Ecuador, with a second subpopulation in southwestern Ecuador and northern Peru. Hence, the largest subpopulation would number considerably more than 1,000 mature individuals. Sub-criterion 2a is not met. There is no evidence that the population size is undergoing extreme fluctuations, and sub-criterion 2b is not met either. Overall, the species does not fulfil sufficient conditions to qualify as Near Threatened under Criterion C. It is therefore considered Least Concern under this criterion.
Criterion D – The population size and range are too large to warrant listing as threatened under Criterion D and thus Plumbeous Hawk qualifies as Least Concern.
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 Plumbeous Hawk (Cryptoleucopteryx plumbea) 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. 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).
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.
Bierregaard, R. O. 1994. Neotropical Accipitridae (Hawks and Eagles). In: del Hoyo, J.; Elliott, A.; Sargatal, J. (ed.), Handbook of the birds of the world, pp. 52-205. Lynx Edicions, Barcelona, Spain.
Bierregaard, R. O.; Christie, D. A. ; Boesman, P. F. D.; Sharpe, C. J.; Marks, J. S. 2020. Plumbeous Hawk (Cryptoleucopteryx plumbea), version 1.0. In: del Hoyo, J.; Elliott, A.; Sargatal, J.; Christie, D. A.; de Juana, E. (eds.). Birds of the World. Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.pluhaw.01 (Accessed 07 May 2020).
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: Cryptoleucopteryx plumbea. http://www.birdlife.org (Accessed 06 May 2020).
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 and Instituto Alexander von Humboldt, Bogota, Colombia.
Stotz, D. F.; Fitzpatrick, J. W.; Parker, T. A.; Moskovits, D. K. 1996. Neotropical birds: ecology and conservation. University of Chicago Press, Chicago, USA.
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.