Archived 2019 topic: Cuban Black Hawk (Buteogallus gundlachii): request for information.

BirdLife species factsheet for Cuban Black Hawk

Cuban Black Hawk (Buteogallus gundlachii) is endemic to Cuba and several offshore islets and cays. In general, the species is uncommon and localised, but can be quite common in areas of optimal habitat (Wiley and Garrido 2005, A. Mitchell in litt. 2007). The population is estimated to number at least 10,000 mature individuals.

Cuban Black Hawk has specialized habitat requirements. It occurs near the coast, where it inhabits mangrove swamps and riverbanks. Occasionally, the species is found outside of forests, on sandy beaches and in palm savannah (del Hoyo et al. 2019).

The population trend has not been quantified; however, the species is thought to decline as wetlands are drained and habitat is degraded.

Currently, Cuban Black Hawk is listed as Near Threatened, approaching the threshold for listing as threatened under Criterion B1ab(i,ii,iii,v). Following IUCN guidelines, the Extent of Occurrence (EOO) for this species has been re-calculated using a Minimum Convex Polygon, which is “the smallest polygon in which no internal angle exceeds 180 degrees and which contains all the sites of occurrence” (IUCN 2001, 2012, Joppa et al. 2016). After re-calculating the EOO for Cuban Black Hawk, this species appears to warrant a change in Red List status. Therefore, we present here our reassessment against all criteria for the species.

Criterion A – There is no information on the population trend. Nevertheless, as a consequence of the destruction and degradation of its habitat, Cuban Black Hawk is suspected to be undergoing a decline, the rate of which has not been directly estimated. Tracewski et al. (2016) measured the forest loss within the species’s range between 2000 and 2012 as c. 47 km2. This roughly equates to a rate of forest loss of 2.2% over three generation (22.8 years) for the species. Given that Cuban Black Hawk occupies both mangrove forest and open savannah (del Hoyo et al. 2019), forest loss alone may not drive a significant population decline. Therefore, we are not able to infer the rate of population decline from the rate of habitat loss within the range. Hence, as the rate of population decline is unknown, Cuban Black Hawk cannot be assessed against this criterion.

Criterion B – Using a Minimum Convex Polygon, the Extent of Occurrence (EOO) has been calculated as 224,000 km2. This value is far too large to approach the threshold for listing as threatened under Criterion B1. As the Area of Occupancy of the species has not been quantified, it cannot be assessed against Criterion B2. Consequently, Cuban Black Hawk may be listed as Least Concern under Criterion B1.

Criterion C – The population of Cuban Black Hawk is estimated at 10,000 mature individuals and assumed to be declining (BirdLife International 2019). However, in order to qualify for listing as threatened under Criterion C, the population decline needs to be either observed, estimated, projected or inferred. In the case of Cuban Black Hawk, the population is suspected to be in decline, which is a lower level of confidence. While we do not have information on the subpopulation structure, observational records from eBird (2019) suggest that the species forms several large subpopulations or could potentially be considered as from one subpopulation. Further information is therefore required to accurately assess the species under this criterion as it could either warrant listing as Near Threatened or Least Concern depending on the subpopulation structure.

Criterion D – The species’s population size is too large to warrant listing as threatened, and thus Cuban Black Hawk may be considered 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, further information regarding subpopulation structure is required to allow for an accurate assessment of the species’s Red List status Cuban Black Hawk (Buteogallus gundlachii)as it could warrant listing as either Near Threatened or Least Concern. We welcome any comments on this discussion.

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.

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

BirdLife International. 2018. Species factsheet: Buteogallus gundlachii. http://www.birdlife.org (Accessed 25/04/2019).

del Hoyo, J.; Collar, N.; Marks, J. S.; Sharpe, C. J. 2019. Cuban Black Hawk (Buteogallus gundlachii). 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/467354 (Accessed 25/04/2019).

eBird. 2019. eBird: An online database of bird distribution and abundance [web application]. eBird, Ithaca, New York. http://www.ebird.org (Accessed 25/04/2019).

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.

Joppa, L. N.; Butchart, S. H. M.; Hoffmann, M.; Bachman, S. P.; Akçakaya, H. R.; Moat, J. F.; Böhm, M.; Holland, R. A.; Newton, A.; Polidoro, B.; Hughes, A. 2016. Impact of alternative metrics on estimates of extent of occurrence for extinction risk assessment. Conservation Biology 30: 362-370.

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.

Wiley, J.W.; Garrido, O.H. 2005. Taxonomic status and biology of the Cuban Black-hawk, Buteogallus anthracinus gundlachii (Aves: Accipitridae). Journal of Raptor Research 39: 351-364.

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2 Responses to Archived 2019 topic: Cuban Black Hawk (Buteogallus gundlachii): request for information.

  1. Red List Team (BirdLife International) says:

    Preliminary proposals
    Based on available information, our proposal for the 2019 Red List is to pend the decision on this species and keep the discussion open until 2020, while leaving the current Red List category unchanged in the 2019 update.

  2. Red List Team (BirdLife International) says:

    Recommended categorisation to be put forward to IUCN
    Following further review, the recommended categorisation for this species has been changed.
    Cuban Black Hawk is now recommended to be listed as Near Threatened, approaching the threshold for listing as threatened under Criteria C2a(ii); D1.
    The final 2019 Red List categories will be published on the BirdLife and IUCN websites in December, following further checking of information relevant to the assessments by both BirdLife and IUCN.

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