Plumbeous Hawk (Cryptoleucopteryx plumbea): revise global status?

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.

References

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.

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7 Responses to Plumbeous Hawk (Cryptoleucopteryx plumbea): revise global status?

  1. Red List Team (BirdLife International) says:

    Global Forest Change data on tree cover loss up to 2019 have now been released and made available via Global Forest Watch. Based on these data, over three generations (17.4 years) approximately 4.2% of tree cover with >30% canopy cover was lost from within the species’s range (Global Forest Watch 2020). This does not affect the above assessment under Criterion A.

  2. Fernando Angulo says:

    This species is not confirmed for Peru birdlist. Birds of Peru (sculenberg et al. 2010), Peru birdlist (Plenge 2020) and SACC doesn’t list this species for the country. On the birdlife account its listed for Peru, based on Clements & Shany (2001), who follows a mention on Walker, M. (2002). Observations from the Tumbes Reserved Zone, dpto. Tumbes, with notes on some new taxa for Peru and a checklist of the area. Cotinga, no. 18: 42. This author mentions that the specis was observed by a third party. Despite being formerly included on Peru list, there is no evidence of it’s presence. M. Plenge mentions on “BIBLIOGRAPHIC REFERENCES OF THE BIRDS OF PERU” (https://sites.google.com/site/boletinunop/bibliographic-references): Records from Tumbes (Hellmayr and Conover 1949) are probably misidentified and are not supported by specimens (T. S. Schulenberg to various persons in litt.).

    • Red List Team (BirdLife International) says:

      Thank you very much for making us aware of the potentially erroneous records from Tumbes and the fact that the species is no longer confirmed for Peru. We have updated the range map accordingly.
      The revised Extent of Occurrence for Plumbeous Hawk is 644,000 km2; the rate of forest loss within the range is 4.2% over three generations (per Global Forest Watch).

  3. The range map needs to be updated further. The species is not known from dry SW Ecuador –it is a real Chocó species confined to Ecuador’s northwest (see Ridgely & Greenfield 2001).

    I strongly disagree with the proposed downlisting to LC. The Tracewski et al. data set used to estimate decline is only measuring deforestation up to 2012. As stated in other comments on Chocó birds, the deforestation in the Ecuadorian Chocó has been 20% over the past 20 years (Finer & Mamani 2019). The deforestation in the lowland and foothill forests that this species depends on is higher than that.

    Unlike other species, this species depends on continuous forest cover and does not thrive in very fragmented areas or disturbed secondary forests. As such, the inferred decline is higher than the deforestation rate.

    Deforestation has soared in Colombia since the peace treaty with the FARC. A total of 197,159 hectares being lost in 2018 according to The Institute of Hydrology, Meteorology and Environmental Studies. Admittedly, most of the deforestation occurs in the Amazon, but the southern Chocó is also affected.

    The species needs to remain listed as Vulnerable under criterion C and C2. In the absence of better data the available population estimate from 2014 should be adapted according to the deforestation rate in the Chocó that has occurred since the date of the estimate. Clearly, the lower boundary will be below the threshold for listing the species as vulnerable. Likewise, current deforestation rates in the species range are very likely to lead to an inferred of >10% over three generations. This, jointly with less than 1000 individuals per subpopulation justifies retaining the species as vulnerable.

  4. Juan Freile says:

    First of all, as already mentioned, the species does not range into NW Peru (or SW Ecuador). This small hawk, as mentioned in previous comment, relies entirely on mature forest or old-grown forest (see Jahn 2011. Bonner Zoologische Monographien 56). As many other birds, it can occasionally be observed in forest borders or fairly degraded secondary forest, but it cannot be considered as tolerant to habitat degradation and loss at all. Estimates by Tracewski et al are outdated and of limited application for SW Colombia and NW Ecuador (see information by Finer & Mamani cited for other species). Estimates of forest loss used separately for Colombia Red Data book and Ecuador Red List indicate higher rates of forest loss, which should be used instead of Tracewski et al’s data.
    In the 2019 assessment of the Ecuador Red List, we estimated a potential decline of at least 30% in the past three and next three generations (meeting criteria A2+A3). This is obviously confined to Ecuador. However, it is classified as NT in Colombia, which harbors the vast majority of this species distribution range. This suggests that downgrading it to LC is misleading.
    It seems likely that the species occurs in low densities, as judged by low number of detections in a long-term study in apparently appropriate habitat (Jahn 2011). This suggests that total population could be exaggerated.

  5. Red List Team (BirdLife International) says:

    Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested by so many people in commenting. The window for consultation is now closed. We will analyse and interpret the new information and post a preliminary decision on this species’s Red List status on this page in early July.

    Thank you once again,
    BirdLife Red List Team

  6. Red List Team (BirdLife International) says:

    Preliminary proposal

    After amending the distribution range map, the EOO has been recalculated as 517,000 sqkm, which exceeds the threshold for listing as threatened under Criterion B1. The information provided by Finer and Mamani (2019) does not allow quantifying the rate of forest loss over three generations within the distribution range. Population estimates for Colombia alone indicate that the national population exceeds 10,000 mature individuals, while declining slowly. We can very precautionarily suspect that the global population size is below 10,000 mature individuals and forming only one subpopulation, and we can further suspect that the species is in slow decline due to habitat loss.

    Based on available information, our preliminary proposal for the 2020 Red List would be to list Plumbeous Hawk as Near Threatened, approaching the threshold for listing as threatened under Criterion C2a(ii).

    There is now a period for further comments until the final deadline in mid-July, 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 2020 Red List categories will be published on the BirdLife and IUCN websites in December 2020/January 2021, following further checking of information relevant to the assessments by both BirdLife and IUCN.

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