Archived 2014 discussion: King Rail (Rallus elegans) is being split: request for information on R. elegans and R. tenuirostris.

The initial deadline for comments on this topic is 17 March 2014, and therefore later than for most other topics currently under discussion.

This is part of a consultation on the Red List implications of extensive changes to BirdLife’s taxonomy for non-passerines

Lynx Edicions and BirdLife International will soon publish the HBW-BirdLife Illustrated Checklist of the Birds of the World, building off the Handbook of the Birds of the World series, and BirdLife’s annually updated taxonomic checklist.

The new Checklist will be based on the application of criteria for recognising species limits described by Tobias et al. (2010). Full details of the specific scores and the basis of these for each new taxonomic revision will be provided in the Checklist.

Following publication, an open and transparent mechanism will be established to allow people to comment on the taxonomic revisions or suggest new ones, and provide new information of relevance in order to inform regular updates. We are also actively seeking input via a discussion topic here regarding some potential taxonomic revisions that currently lack sufficient information.

The new Checklist will form the taxonomic basis of BirdLife’s assessments of the status of the world’s birds for the IUCN Red List. The taxonomic changes that will appear in volume 1 of the checklist (for non-passerines) will begin to be incorporated into the 2014 Red List update, with the remainder, and those for passerines (which will appear in volume 2 of the checklist), to be incorporated into subsequent Red List updates.

Preliminary Red List assessments have been carried out for the newly split or lumped taxa. We are now requesting comments and feedback on these preliminary assessments.

King Rail Rallus elegans is being split into R. elegans and R. tenuirostris, following the application of criteria set out by Tobias et al. (2010) and consultation of genetic evidence (Maley and Brumfield 2013).

Prior to the taxonomic change, R. elegans (BirdLife species factsheet) was listed as being of Least Concern, on the basis that it was not thought to approach the thresholds for Vulnerable under any of the IUCN Red List criteria.

R. tenuirostris is found in highland freshwater marshes in central Mexico, from southern Nayarit, Jalisco, Guanajuato and southern San Luis Potosi, south to Guerrero, Morelos and Puebla, and on the Pacific slope in Colima (Warner and Dickerman 1959, Williams 1989, Howell and Webb 1995, Taylor and van Perlo 1998). It has been recorded at 800-2,500 m at least (Williams 1989). In the mid-20th century, the species was reported to be common in extensive marshes west of Mexico City, although the edges of these habitats were being grazed (Warner and Dickerman 1959). The species has also been recorded in smaller seasonal areas of marsh, probably through dispersal from permanent wetlands in the rainy season (Williams 1989). Permanent wetlands in central Mexico are reported to be in a degraded condition and the total area of habitat available to this species becomes very limited towards the end of the typical dry season. Furthermore, these habitats have been reported as under threat from increasing agricultural, industrial and urban development (Williams 1989). Further information on this species is requested, including the likely population size, population and habitat trends, and details of threats.

R. elegans (as defined following the taxonomic change, and incorporating ramsdeni) is a widespread and mostly migratory inhabitant of freshwater and brackish wetlands, including modified areas, in eastern North America, eastern Mexico and Cuba (Taylor and van Perlo 1998). The species is in decline owing mainly to the loss, fragmentation and degradation of wetland habitats (Cooper 2008). Qualitative observations and Breeding Bird Survey (BBS) data are indicative of declines across most of the species’s range in the USA, although caution is advised in using BBS data, as the methods and coverage of these surveys may not provide the most reliable data for this species (reviewed by Cooper 2008).

Further information is requested. If the species is observed, estimated or suspected to be undergoing a population decline approaching 30% over 14 years (estimate of three generations) the species may qualify as Near Threatened under criterion A.


Cooper, T. R. (2008) King Rail (Rallus elegans) Conservation Plan, Version 1. Fort Selling, MN: U.S. Fish and Wildlife Service.

Howell, S. N. G. and Webb, S. (1995) A guide to the birds of Mexico and northern Central America. Oxford, UK: Oxford University Press.

Maley, J. M. and Brumfield, R. T. (2013) Mitochondrial and next-generation sequence data used to infer phylogenetic relationships and species limits in the clapper/king rail complex. Condor 115(2): 316–329.

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

Tobias, J. A., Seddon, N., Spottiswoode, C. N., Pilgrim, J. D., Fishpool, L. D. C. and Collar, N. J. (2010) Quantitative criteria for species delimitation. Ibis 152: 724–746.

Warner, D. W. and Dickerman, R. W. (1989) The status of Rallus elegans tenuirostris in Mexico. Condor 61: 49–51.

Williams, S. O., III (1989) Notes on the rail Rallus longirostris tenuirostris in the highlands of central Mexico. Wilson Bulletin 101: 117–120.

This entry was posted in Americas, Archive, Caribbean, Central America, North America and tagged . Bookmark the permalink.

1 Response to Archived 2014 discussion: King Rail (Rallus elegans) is being split: request for information on R. elegans and R. tenuirostris.

  1. Andy Symes says:

    Preliminary proposals

    Based on available information, our preliminary proposals for the 2014 Red List would be to treat:

    R. elegans as Near Threatened, approaching the thresholds for classification as Vulnerable under criterion A2ac+3ac+4ac

    R. tenuirostris as Near Threatened, thought to approach the thresholds for classification as Vulnerable under criterion C2a(i).

    There is now a period for further comments until the final deadline of 14 May, after which recommended categorisations will be put forward to IUCN.

    The final Red List categories will be published on the BirdLife and IUCN websites in mid-2014, following further checking of information relevant to the assessments by both BirdLife and IUCN.

Comments are closed.