Justification of Red List Category
This species is listed as Endangered because its range is very small and is contracting owing to widespread habitat loss and degradation.
The population estimate of 1,000-2,499 mature individuals is derived from Collar et al. (1992), Lozano (1993) and F. G. Stiles (in litt. 1999). This equates to 1,500-3,749 individuals in total, rounded here to 1,500-4,000 individuals.
This species's population is suspected to be decreasing at a moderate rate, in line with habitat loss and degradation within its range.
Rallus semiplumbeus occurs on the Ubaté-Bogotá plateau in Cundinamarca and Boyacá in the east Andes of Colombia. The race peruvianus of Peru is only known from its type material, collected in 1886, and is probably extinct (del Hoyo et al. 1996). In Boyacá, it is known from Laguna de Tota and, in Cundinamarca, it has been recorded at a minimum of 21 localities. The Ubaté-Bogotá plateau formerly held enormous marshes and swamps, but few lakes with suitable habitat remain (Fjeldså and Krabbe 1990). Although declining, it is still uncommon to fairly common, with notable populations including c.400 birds at Laguna de Tota, c.50 territories at Laguna de la Herrera, c.110 birds at Parque la Florida (Lozano 1993), and those at La Conejera Marsh and Laguna de Fúquene (F. G. Stiles in litt. 1999).
It occurs in the temperate zone, at 2,500-4,000 m (occasionally as low as 2,100 m), in savanna and páramo marshes, but it is unclear whether páramo birds breed locally. Characteristic wetland habitats are fringed by dense, tall reeds, bulrushes and vegetation-rich shallows (F. G. Stiles in litt. 1999). It appears to be particularly associated with the presence of Typha and two other aquatic plants, Limnobium laevigatum and Eichornia crassipes (O. Cortes in litt. 2007). It uses flooded pasture and small overgrown dykes and ponds, but probably not for breeding (Fjeldså 1990, P. G. W. Salaman in litt. 1999). Breeding probably takes place in July-September (Taylor 1996). Nests have been found in Scirpus and Typha beds adjoining shallow water (F. G. Stiles in litt. 1999). It feeds primarily on aquatic invertebrates and insect larvae, but also takes worms, molluscs, dead fish, frogs, tadpoles and plant material.
Drainage has caused massive habitat loss on the Ubaté-Bogotá plateau, and few suitably vegetated marshes remain because of pollution and siltation. All major savanna wetlands are seriously threatened, mainly by drainage, but also by agricultural encroachment, erosion, dyking, eutrophication (caused by untreated sewage effluent and agrochemicals), insecticides, tourism, hunting, burning, trampling by cattle, harvesting of reeds, fluctuating water-levels and increased water demand. The fringing habitat at Laguna de Tota has been reduced to less than 2 km2, and its continuing decay is reducing food availability (Varty et al. 1986). Laguna de la Herrera is affected by hunting, cattle trampling and irrigation schemes, and La Conejera Marsh and Laguna de la Florida are threatened by road construction and illegal settlement (Lozano 1993, P. G. W. Salaman in litt. 1999, F. G. Stiles in litt. 1999). Construction of a new road system from Bogotá may open up wetland tracts to colonisation, agriculture, hunting and the introduction of invasive species such as rats and domestic cats and dogs. Feral cats are common in the Bogotá wetland but it is not known how much threat they pose (O. Cortes in litt. 2007). A dog was observed killing a Bogota Rail in Jaboque wetland (O. Cortes in litt. 2007).
Conservation Actions Underway
Occurs within one national protected area, Chingaza Natural National Park, as well as 33 ha of La Florida wetland that is part of a District Park (Loziano 2002, Taylor and Sharpe 2016). However, other savanna wetlands are unprotected apart from Laguna de Pedro Palo and Fuquene.
25 cm. Very vocal, medium-sized rail. Slate-grey sides of face to belly, with pale throat and black flanks, coarsely banded white. Dull olive-brown streaked black above, with dull rufous shoulders. Conspicuous dull red bill and legs. Similar spp. Differs from sympatric rails in grey underparts, and red bill and legs. Voice Loud, sharp, piercing peep, and rapid, short chattering when alarmed.
Text account compilers
Benstead, P., Pilgrim, J., Sharpe, C J, Symes, A., Khwaja, N.
Cortés, O., Salaman, P., Stiles, F.
BirdLife International (2019) Species factsheet: Rallus semiplumbeus. Downloaded from http://www.birdlife.org on 21/10/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 21/10/2019.