Black Rail (Laterallus jamaicensis): revise global status?

Black Rail (Laterallus jamaicensis) occurs very locally throughout the Americas and the Caribbean. It is found along the east coast of the U.S.A., in California and southward in a few, disjunct locations south to Panama, on the Greater Antilles, in Peru, Chile and Argentina. The species is very rare; the global population is estimated to number 28,500-91,200 mature individuals. Of these, 15,000-70,000 mature individuals belong to the nominate subspecies jamaicensis, which occurs on the east coast of the U.S.A., in Central America and in the Caribbean. The species inhabits fresh and saline marshes, wet meadows and savanna with dense vegetation for shelter. It occupies sites with shallower water than other rallids (Nicolette and Barrett 2015). 

The species is suspected to be in decline due to habitat loss and range contractions, particularly in the U.S.A. Modelling results show that the species is highly likely to become extinct in the U.S.A. by 2100 (USFWS 2018). The most severe threat is the massive degradation, conversion and fragmentation of wetlands within its range. Further threats include pollution, fire suppression regimes which result in overgrowing of wetlands with woody vegetation, groundwater abstraction, predation by invasive species (fire ants, feral pigs, mongooses), sea level rise, pollution and agricultural expansion (Eddleman et al. 1994, Taylor and van Perlo 1998, Taylor and Christie 2019, USFWS 2018, 2019).

Black Rail is currently listed as Near Threatened, approaching the threshold for listing as threatened under Criteria A2c+3c+4c (BirdLife International 2019), indicating a rapid decline in area, extent and/or quality of habitat. However, incorporating new information on the rate of population decline of the nominate subspecies, 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 – The population of Black Rail is suspected to be in decline based on habitat loss and deterioration within its range as well as on predation by invasive species. The rate of population decline has not been directly estimated throughout the range. It has been assumed that the species declined at a rate of 20-29% over three generations (11.1 years). Recent surveys of the subspecies jamaicensis in the U.S.A., however, give evidence of a 90% population decline along the east coast of the country since the early 1990s (Kurth 2018). This decline equates to a rate of c. 60-69% over three generations.

We can precautionarily assume that subspecies jamaicensis is declining at this rate throughout its entire range; indicating that 15,000-70,000 mature individuals decline at 60-69% over three generations. Unless further information becomes available, we can assume that the remaining 12,000-25,000 mature individuals continue to decline at 20-29% over three generations. This means that the global population has declined at a rate of roughly 50-60% over three generations. It is likely that the decline continues at this rate into the future. Thus, Black Rail may be listed as Endangered under Criteria A2ace+3ce+4ace.

Criterion B – The species’s range is far too large to qualify for listing as threatened under Criterion B. Thus, Black Rail may be listed as Least Concern under this criterion.

Criterion C – The population of Black Rail is estimated to number 28,500-91,200 mature individuals. Even though the species is declining, its population size is too large to warrant listing as threatened under Criterion C. As such, Black Rail may be considered Least Concern under this criterion.

Criterion D – The population size and range of this species are far too large to warrant listing as threatened under Criterion D; thus Black Rail may be considered Least Concern under this criterion.

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 proposed that Black Rail (Laterallus jamaicensis) be listed as Endangered under Criteria A2ace+3ce+4ace. We welcome any comments on this proposed listing and specifically request up-to-date information about the rate of decline in the populations outside of the U.S.A.

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. 2019. Species factsheet: Laterallus jamaicensis. http://www.birdlife.org (Accessed 29/04/2019).

Eddleman, W. R.; Flores, R. E.; Legare, M. L. 1994. Black Rail (Laterallus jamaicensis). In: Poole, A.; Gill, F. (eds.), The Birds of North America, No. 123, pp. 1-20. The Academy of Natural Sciences, and The American Ornithologists’ Union, Philadelphia, and Washington, D.C., U.S.A.

Kurth, J. W. 2018. Endangered and threatened wildlife and plants; 12-month petition finding and threatened species status for Eastern Black Rail with a section 4(d) rule. USFWS.

Nicolette, S.; Barrett, K. 2015. Managed habitats increase occupancy of Black Rails (Laterallus jamaicensis) and may buffer impacts from sea level rise. Wetlands 35(6): 1065-1076.

Taylor, B.; Christie, D. A. 2019. Black Rail (Laterallus jamaicensis). 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/53602 (Accessed 29/04/2019).

Taylor, B.; van Perlo, B. 1998. Rails: a guide to the rails, crakes, gallinules and coots of the world. Pica Press, Robertsbridge, UK.

USFWS. 2018. Species status assessment report for the eastern black rail (Laterallus jamaicensis jamaicensis), Version 1.2. June 2018. Atlanta, GA, U.S.A.

USFWS. 2019. Eastern black rail Laterallus jamaicensis jamaicensis. https://www.fws.gov/southeast/wildlife/birds/eastern-black-rail/ (Accessed 29/04/2019).

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4 Responses to Black Rail (Laterallus jamaicensis): revise global status?

  1. Chris Elphick says:

    There appear to be some mistakes in the preamble above. First, it does not recognize that black rails occur in the western USA. Second, surely the statement about extinction by 2011 is a typo. I’m also surprised that this exhaustive review on the species is not cited:
    https://rcngrants.org/sites/default/files/final_reports/RCN%202011-1%20CCBTR-16-09_Eastern%20Black%20Rail%20Status%20Assessment_final.pdf
    Estimating decline based on population size might be hard, but an alternative might be to estimate the portion of the historic range from which the species has disappeared in recent decades – this area is considerable.

    • Red List Team (BirdLife International) says:

      Thank you very much for your comment. Yes, there was indeed a typo in the preamble; thank you for pointing it out. We apologize for that, and have corrected it now. Thank you also for forwarding the status report. We will make sure to cite it in the updated Factsheet of the species.
      Yes you are right, estimating the rate of decline proved to be particularly challenging for this species. While there are extensive surveys and trend estimates available for the eastern subspecies, there is much less information on hand for the populations in California and Central and South America. Quantifying the rate of habitat loss may be a way out. The main question here is: Is the rate of decline in the eastern subspecies so large that it outweighs a potentially slower decline or even stable trend in the rest of the range?

  2. Red List Team (BirdLife International) says:

    Preliminary proposal
    Based on available information, our preliminary proposal for the 2019 Red List would be to adopt the proposed classifications 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 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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