Justification of Red List Category
This species has a small range and a moderately small population. Both its range and population are probably in decline owing to increasing habitat loss and degradation. However, the range is not yet severely fragmented or restricted to few locations. For these reasons, the species is classified as Near Threatened.
Partners in Flight (2019) estimate the population to number <50,000 individuals; however, this is likely an overestimate as the species occurs at a low density (A. Townsend Peterson in litt. 2016). Thus it is here placed in the band for 10,000-19,999 mature individuals.
The population is suspected to be in decline owing to on-going habitat destruction and degradation (del Hoyo et al. 2005). The State of North America's Birds assesses the population trend as steeply declining (NABCI 2016).
This species is restricted to c.12 sites in west-central Veracruz, north Oaxaca and extreme east Puebla, south Mexico, where it is fairly common but local (Howell and Webb 1995, Gómez de Silva 1997). It occupies a limited area of suitable habitat (forested karst outcrops) within a small range (Howell and Webb 1995, Whittingham and Atkinson 1996, Gómez de Silva 1997, Kroodsma and Brewer 2016).
The species inhabits naturally patchy limestone outcrops in steep hilly country covered by lowland evergreen and semi-evergreen forest at elevations of 75-1,000 m (Howell and Webb 1995, Whittingham and Atkinson 1996, Gómez de Silva 1997). It also occurs in shade coffee plantations and adjacent to quarrying operations, and two pairs are known to have had their territories in less than 0.5 ha of habitat, indicating some tolerance of habitat degradation, disturbance and fragmentation (Atkinson et al. 1993, Gómez de Silva 1997). It feeds mostly on invertebrates, but also takes small fruits (del Hoyo et al. 2005). Nest-building has been observed in March, nests with eggs have been found in May, and adults have been recorded feeding fledglings in July and August. Of three known nests, two were in rock crevices and the other in the roof of a cave. The species lays three eggs (del Hoyo et al. 2005).
The forested limestone outcrops inhabited by the species are poor for cultivation compared with the surrounding flatter land and have been spared complete conversion to maize fields and cattle pasture (Stattersfield et al. 1998, M. G. Pérez-Villafaña in litt. 1999). It is more threatened by the expansion of limestone-quarrying, although its habitat is increasingly threatened by encroaching cultivation and cattle ranches (Gómez de Silva 1997). Forest loss within the species's range is currently estimated at ~1% across the stipulated ten year period (Tracewski et al. 2016). Some habitat has undoubtedly been lost to the extensive Presa Miguel Alemán reservoir in north Oaxaca (Stattersfield et al. 1998). There are no populations within protected areas (Pérez-Villafaña et al. 2003), and given its relatively narrow ecological tolerance, this could be a cause for concern.
Conservation Actions Underway
The species is included on the 'Watch List' of the State of North America's Birds as a species of high conservation concern (NABCI 2016).
Text account compilers
Wheatley, H., Everest, J.
Ashpole, J, Gomez de Silva, H., O'Brien, A., Peterson, A.T., Pérez-Villafaña, M., Sharpe, C.J., Taylor, J. & Vidal, R.
BirdLife International (2021) Species factsheet: Hylorchilus sumichrasti. Downloaded from http://www.birdlife.org on 07/05/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 07/05/2021.