The species occurs in the temperate zone, at 2,500-4,000 m (occasionally as low as 2,100 m), in savanna and páramo marshes. 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 tall reeds, preferring Schoenoplectus californicus, Typha, Juncus and two other aquatic plants, Limnobium laevigatum and Eichornia crassipes (O. Cortes in litt. 2007; Renjifo et al. 2016; Pérez-Guevara and Botero-Delgadillo 2020; L. Rosselli in litt. 2020). The species survives in small patches of habitat; already wetlands as small as 0.5 ha are probably suitable for breeding (Fundación ProAves in litt. 2020; Taylor and Sharpe 2020). It has occasionally been reported from heavily degraded wetlands and even small streams in the city of Bogotá (Fundación ProAves in litt. 2020). It uses flooded pasture and small overgrown dykes and ponds, but probably not for breeding (Fjeldså 1990, P. Salaman in litt. 1999). It feeds primarily on aquatic invertebrates and insect larvae, but also takes worms, molluscs, dead fish, frogs, tadpoles and plant material. Breeding probably takes place year-round (Taylor 1996; Renjifo et al. 2016). Nests have been found in Schoenoplectus and Typha beds adjoining shallow water (F. G. Stiles in litt. 1999).

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). The species has been recorded at over 150 localities in montane and páramo wetlands and lakes (Fundación ProAves in litt. 2020). Notable sites include Laguna de Tota, Laguna de la Herrera, Parque La Florida, Conejera Marsh and Laguna de Fúquene (Lozano 1993; F. G. Stiles in litt. 1999; Renjifo et al. 2016).

Conservation Actions Underway
The species occurs within Chingaza, Sumapaz and probably Cocuy Natural National Parks (Renjifo et al. 2016). 33 ha of La Florida wetland is part of a District Park (Loziano 2002). It further occurs in six protected urban wetlands in Bogota (L. Rosselli in litt. 2020), but many wetlands within the range are unprotected. A community-based monitoring programme has been established in the Laguna de Fúquene (Renjifo et al. 2016). The Bogota Rail Project, led by Humedales de Bogotá and Bogotá Birding, is carrying out awareness-raising campaigns in schools (O. Cortes in litt. 2020). Environmental education workshops for local schoolchildren are being held in the Tota and Fúquene areas (Renjifo et al. 2016).

Conservation Actions Proposed
Survey suitable habitat to identify further occupied localities. Implement monitoring programmes to assess potential declines. Assess the effects of predation by invasive mammals (O. Cortes in litt. 2007). Produce a species action plan.
Effectively protect wetland areas that harbour large populations, in particular Laguna de Tota (P. Salaman in litt. 1999; L. Rosselli in litt. 2020). Restore habitat. Consider eradicating invasive predators from occupied sites. Continue and expand awareness campaigns.