Justification of Red List Category
After its discovery in 1955, the species has not been recorded until six individuals were found in 2016. Although it persists within a large national park, it probably has a tiny population which is likely to be declining owing to ongoing forest loss in the region (Collar et al. 1992). For these reasons it qualifies as Critically Endangered.
The population is precautionarily estimated to number fewer than 50 individuals and mature individuals, for consistency with other species of similar status.
The population is considered to be in decline (suspected at a rate of 1-19% over ten years), owing to ongoing habitat degradation in the region. This part of the Andes is one of the most seriously threatened by deforestation for agriculture (Sharpe and Lentino 2008, 2015).
Grallaria chthonia is known only from the type-locality, at Hacienda la Providencia on the río Chiquito in south-west Táchira, west Venezuela, where four specimens were collected in 1955-1956. The type locality has since been deforested, although there is still forest in the vicinity; specific searches in September 1990 and December 1996 failed to find the species (M. Pearman in litt. 1995, Boesman 1998, P. Boesman in litt. 2000). Until recently, guerilla activities near the Colombian border prevented thorough field surveys. Only in June 2016, six individuals were rediscovered when a search led by Jhonathan Miranda reconstructed the route of the expedition of 1955 to locate the site of the original discovery (Gilman 2017). However, subsequent surveys of the area failed to record the species (Gilman 2017).
The species occurs in the understory of dense cloud-forest at elevations of 1,800-2,100 m.
In 1990, habitat at the type-locality was reportedly undisturbed above 1,150 m, but deforestation was proceeding rapidly in the area (M. Pearman in litt. 1995). In 1996, the río Chiquito valley was entirely coffee plantations below 1,600 m, with much habitat at 1,900-2,200 m converted to grow potatoes and other vegetables (P. Boesman in litt. 2000, Sharpe and Lentino 2008). The next valley to the west had some habitat at c.1,850 m, and there is presumably habitat in between these two valleys (P. Boesman in litt. 2000). Some 17% of the El Tamá National Park has been affected by agriculture, especially coffee plantations, and small-scale cattle raising (Sharpe and Lentino 2008, 2015).
Conservation Actions Underway
The type-locality is within El Tamá National Park. This species is considered Critically Endangered at the national level in Venezuela (Sharpe 2008, Sharpe and Lentino 2015).
17 cm. Medium-sized antpitta. Brown upperparts with grey crown and nape, and black barring on mantle. Brown throat and ear-coverts with white malar stripe. Whitish lower underparts with greyish barring on flanks and breast. Similar spp. Scaled Antpitta G. guatimalensis has ochraceous lower underparts and lacks barring on breast and flanks. Voice Unknown.
Text account compilers
Mahood, S., Hermes, C., Pople, R., Capper, D., Sharpe, C.J., Symes, A.
Boesman, P., Sharpe, C J, Pearman, M.
BirdLife International (2020) Species factsheet: Grallaria chthonia. Downloaded from http://www.birdlife.org on 06/08/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 06/08/2020.