Archived 2020 topic: Jamaican Crow (Corvus jamaicensis): revise global status?

BirdLife species factsheet for Jamaican Crow

Jamaican Crow (Corvus jamaicensis) is endemic to Jamaica. It is widely distributed in a variety of habitats, from wet forests to open woodland, preferring secondary growth and heavily disturbed, anthropogenic habitats including agricultural areas and settlements (Graves and Schmidt 2015, Marzluff 2020). The species appears to react well to habitat conversion and it is hypothesised that the population is increasing as the range expands into open habitats (Graves and Schmidt 2015, Marzluff 2020). Potential threats to Jamaican Crow include extensive deforestation, pathogens, nest predation and hunting; however none of these appear to impact the population size (Graves and Schmidt 2015).

Jamaican Crow is currently listed as Least Concern (BirdLife International 2020). However, new information regarding the population size suggests that the species may warrant a change in Red List status. Therefore, it will be re-assessed against all Red List criteria:

Criterion A – The species appears to be increasing as it is locally expanding its range into open, secondary and converted habitats (Madge and Burn 1993, Graves and Schmidt 2015), but detailed data to conclusively confirm this trend are lacking (Graves and Schmidt 2015). The species is here tentatively retained as increasing; it therefore qualifies as Least Concern under Criterion A.

Criterion B – The Extent of Occurrence (EOO) for this species is 13,500 km2; the maximum Area of Occupancy (AOO), as calculated by a 4 km2 grid over the area of mapped range, is 12,536 km2. Hence, the EOO meets the threshold for Vulnerable (EOO < 20,000 km2). 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). Some potential threats are known to the species; however, they do not appear to impact the population size and hence are very unlikely to extirpate large parts of the population within the next generation length (5.8 years; see Bird et al. 2020)*. The number of locations** of occurrence can therefore not be quantified, and the species does not meet condition a. There is furthermore no evidence that habitat availability or population size are in decline or undergoing severe fluctuations, and subcriteria b and c are not met either. Therefore, even though the EOO is small, the species does not qualify for listing as threatened under Criterion B, and is therefore considered Least Concern under this criterion.

Criterion C – The population size of Jamaican Crow has been placed in the band 1,300-1,800 mature individuals, which likely belong to just one subpopulation. As there is currently no evidence for a population decline however, the species qualifies as Least Concern under this criterion.

Criterion D – The population size is estimated at 1,300-1,800 mature individuals. Jamaican Crow may therefore be considered Near Threatened, approaching the threshold for listing as threatened 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 Jamaican Crow (Corvus jamaicensis) be listed as Near Threatened, approaching the threshold for listing as threatened under Criterion D1. 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).

**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.

References

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: Corvus jamaicensis. http://www.birdlife.org (Accessed 27 April 2020).

eBird. 2020. eBird: An online database of bird distribution and abundance [web application]. eBird, Ithaca, New York. http://www.ebird.org (Accessed 27 April 2020).

Graves, G. R.; Schmidt, B. K. 2015. Distribution, abundance, and conservation status of the Jamaican Crow, Corvus jamaicensis. Caribbean Naturalist 27: 1-18.

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 Categories and Criteria. Version 14. http://www.iucnredlist.org/documents/RedListGuidelines.pdf.

Marzluff, J. 2020. Jamaican Crow (Corvus jamaicensis), 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.jamcro1.01 (Accessed 27 April 2020).

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3 Responses to Archived 2020 topic: Jamaican Crow (Corvus jamaicensis): revise global status?

  1. Red List Team (BirdLife International) says:

    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,
    BirdLife Red List Team

  2. Red List Team (BirdLife International) says:

    Preliminary proposal

    Based on available information, our preliminary proposal for the 2020 Red List would be to adopt the proposed classification outlined in the initial forum discussion.

    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 those in 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.

  3. Red List Team (BirdLife International) says:

    Recommended categorisation to be put forward to IUCN

    The final categorisation for this species has not changed. Jamaican Crow is recommended to be listed as Near Threatened, approaching the threshold for listing as threatened under Criterion D1.

    Many thanks for everyone who contributed to the 2020 GTB Forum process. 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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