Justification of Red List Category
Although the range of this species has been extended considerably recently, it is still only known from five locations, and much of the intervening habitat is likely to be unsuitable. It occurs at a very low density and has highly specific habitat requirements, so it probably has a very small population. Habitat loss is ongoing within its range so it is likely to be declining. For these reasons it is listed as Endangered.
The population is estimated to number 250-999 individuals based on an assessment of known records, descriptions of abundance and range size. This is consistent with recorded population density estimates for congeners or close relatives with a similar body size, and the fact that only a proportion of the estimated Extent of Occurrence is likely to be occupied. This estimate is equivalent to 167-666 mature individuals, rounded here to 150-700 mature individuals.
Forest degradation is ongoing in the region, thus the species's population is suspected to be declining slowly.
Grallaria ridgelyi was discovered in 1997 in southern Ecuador. Although its range has been estimated as Tapichalaca Biological Reserve environs, east and south-east to the Cordillera de Tzunantza and southern Cordillera del Condor, south-west to the río Isimanchi, and possibly further north and south (Krabbe et al. 1999), it is currently known only from Tapichalaca Biological Reserve (formerly Quebrada Honda Reserve), adjacent parts of Podocarpus National Park, Cerro Toledo, San Luis, rio Blanco and the Cordillera del Condor, Peru (Heinz et al. 2005, O'Neill 2006). Initially, three specimens were taken and c.12 pairs observed (Koeppel 1998), but two further specimens have since been collected in both Ecuador and Peru and additional birds noted (Krabbe et al. 1999, O'Neill 2006). It occurs at an estimated density of six pairs per km2 at the type-locality (Krabbe et al. 1999), but at lower densities elsewhere. Very little of the habitat between the known sites is high enough for the species and therefore unlikely to be occupied (R. S. Ridgely in litt. 2007). It is likely to have a very small population.
It apparently inhabits the undergrowth of wet, montane evergreen forest, with bryophyte-clad, generally low trees and bamboo, within the subtropical zone, at 2,300-2,680 m (Krabbe et al. 1999). The birds seem to require the existence of a stream (which can be quite small, but must remain moist), and spend a large majority of their time very close to this (R. S. Ridgely in litt. 2007, 2012). Radio telemetry indicates that birds have a large (20-40 hectares) home range (R. S. Ridgely in litt. 2007). Evidence suggests that it breeds in October-November (Krabbe et al. 1999) and a nest is described by Greeney and Juiña (2010). Stomach contents comprised invertebrate remains, including insects (beetles and ants) and their larvae, worms and millipedes (Krabbe et al. 1999).
The Tapichalaca Biological Reserve is situated near a road that is frequently used for commercial transport, and a road-widening project in 2009-2010 probably affected two territories here (R. S. Ridgely in litt. 2012). Much of the range is threatened by logging and gold mining, including areas within Podocarpus National Park (Koeppel 1998). Forest degradation is ongoing at a slow rate throughout the region.
Conservation Actions Underway
The type-locality is within Tapichalaca Biological Reserve, a 35 km2 area purchased and managed following the species's discovery (Krabbe et al. 1999, Sornoza Molina 2000, Ridgely and Greenfield 2001). It also occurs in the adjacent Podocarpus National Park (Krabbe et al. 1999), but only along the southern border, where threats from human settlement and gold miners are most concentrated (Snyder et al. 2000). A revised management plan for the area has been devised, and a public awareness campaign highlighting the park's importance has been initiated (Snyder et al. 2000).
22 cm. Remarkably plumaged, large antpitta. Black crown. Dark grey nape and much of face, except bold white moustachial. Grey-brown upperparts, with more rusty-tinged wings and dark-streaked mantle and scapulars. Whitish grey underparts. Grey legs and all-black, deep-based bill. Reddish irides. Voice Song consists of 6-10 or more notes separated by intervals of 1-2 seconds, distinctly lower pitched than songs of its closest relatives. Softer, two-noted ho-co call.
Text account compilers
Benstead, P., Capper, D., Mahood, S., Pople, R., Sharpe, C J, Stuart, T., Díaz, D.
Simpson, N., Schaefer, H.M., Valqui, T., Waliczky, Z., Aucca Chutas, C., Ridgely, R., Sornoza, F., Krabbe, N., Marks, T.
BirdLife International (2021) Species factsheet: Grallaria ridgelyi. Downloaded from http://www.birdlife.org on 18/10/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 18/10/2021.