Justification of Red List Category
This species is classified as Critically Endangered as the population, which is confined to a single area, is now thought to be extremely small and is undergoing continued decline, possibly due to the effect of invasive species. It is undoubtedly highly threatened and in need of urgent conservation action to investigate and halt this decline.
Given the scarcity of recent sightings, the population is thought to number fewer than 250 mature individuals (A. Kirkconnell in litt. 2009, A. Mitchell in litt. 2009), and so is placed in the band 50-249 mature individuals, a range similarly estimated between 2000-2008 by Wetlands International (2020). This equates to 75-374 individuals in total, rounded to 70-400 individuals here.
The paucity of recent records and anecdotal evidence suggest that there has been a significant decline since the year 2000, though the rate of decline is unknown (A. Kirkconnell in litt. 2009; A. Mitchell in litt. 2009). Surveys are required to confirm this decline, though declines have been noted in resident Spotted Rail Porzana maculatus and King Rail Rallus elegans as well as migrant Sora P. carolina (A. Mitchell in litt. 2012).
This species occurs away from the coast and more commonly on the western side (A. Mitchell in litt. 2016) of the 4,500 km2 Zapata swamp, south-west Cuba. Four individuals were collected near Santo Tomás in 1927, and the species was found easily in 1931. There were no subsequent records until the 1970s, when its voice was thought to have been recorded and birds were found in the south-east of Laguna del Tesoro. There are also records from Peralta, within the Zapata swamp (A. Kirkconnell in litt. 2007) and La Turba in November 2014 (A. Mitchell in litt. 2014). It may occur elsewhere within the swamp (A. Mitchell in litt. 1998), and was formerly even more widespread, with fossil bones found in cave deposits in Havana, Pinar del Río, on the Isla de la Juventud (Olson 1974, Garrido 1985, E. Abreu in litt. 1999), and Sancti Spiritus (W. Suárez per A. Kirkconnell in litt. 2012). It is now thought to have an extremely small population given the paucity of recent records and threats to the species, with anecdotal evidence suggesting a significant decline since the year 2000 (A. Kirkconnell in litt. 2009, A. Mitchell in litt. 2009).
It inhabits a flooded, tall (1.5-2.0 m) grassland ecosystem comprising dense, tangled, bush-covered swamp with low trees, where 'arraigán' Myrica cerifera brush, Salix longipes, sawgrass Cladium jamaicensis and cattails Typha angustifolia are common (King 1981, Regalado Ruíz 1981, E. Abreu in litt. 1999, Kirkconnell et al. 1999). C. jamaicensis is the preferred vegetation for nesting and feeding (E. Abreu in litt. 1999). Breeding takes place around September, and possibly in December and January (Raffaele et al. 1998). Nests are apparently situated on raised tussocks above water-level (Bond 1984). Birds may disperse during wet-season floods, returning to permanently inundated areas in the dry season (A. Mitchell in litt. 1998).
Dry-season burning is potentially devastating. Introduced mongooses and rats are probably important predators. Exotic African Catfish Clarias gariepinus may also predate juveniles, a problem exacerbated by the species's nidifugous nature, and there is anecdotal evidence that there has been a dramatic decline in population in all rallids at the site since catfish were introduced in 2000 (A. Kirkconnell in litt. 2009, A. Mitchell in litt. 2009, 2012). There was formerly extensive grass-cutting for roof thatch (A. Kirkconnell in litt. 2016).
Conservation Actions Underway
Two known sites are in protected areas: the well protected and managed Corral de Santo Tomás Faunal Refuge (A. Mitchell in litt. 1998), and a nature tourism area including the Laguna del Tesoro. Surveys for the species throughout its potential range took place in 1998 and 1999 (Cotinga 10 1998, Kirkconnell et al. 1999), whilst a survey in 2014 found just one individual (A. Mitchell in litt. 2014).
Conservation Actions Proposed
Urgently conduct surveys to assess current population size, distribution and status. Assess the impact of introduced species and research ways to mitigate their effects. Conduct research into the ecology of this species. Control dry season burning. Survey for any additional threats. Investigate current habitat management practices and recommend future strategies (A. Mitchell in litt. 1998).
29 cm. Medium-sized, moderately long-billed, blue-and-brown rail. Brown upperparts, slate grey underparts with grey hindflanks, white or buffy undertail and white throat, short white supercilium, red eye, yellow bill with red base, and orange legs (A. Kirkconnell in litt. 2012). Very short wings and virtually flightless. Similar spp. Spotted Rail Pardirallus maculatus is heavily spotted. Voice Unknown. Vocalisations previously ascribed to this species ("a bouncing call cutucutu-cutucutu-cutucutu") is now known to belong to Spotted Rail (A. Kirkconnell in litt. 2009). A Limpkin Aramus guarauna-like kuvk kuck is described by Bond (1979).
Text account compilers
Martin, R., Everest, J., Wheatley, H.
Abreu, E., Ashpole, J, Benstead, P., Calvert, R., Capper, D., Kirkconnell, A., Mahood, S., Mitchell, A., Pilgrim, J., Sharpe, C.J. & Wege, D.
BirdLife International (2021) Species factsheet: Cyanolimnas cerverai. Downloaded from http://www.birdlife.org on 16/10/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 16/10/2021.