Data Zone
Justification of Red List category
Based on accelerating deforestation across its range, its dependence on primary forest and susceptibility to habitat fragmentation, it is suspected that the population of this species is undergoing rapid declines. It is therefore listed as Vulnerable.
Population justification
The global population size has not been quantified, but the species is described as uncommon to fairly common within its small range, though patchily distributed (del Hoyo et al. 2003, Lees 2020, eBird 2022). Its poorly known distribution hinders an extrapolation of the population size based on density estimates of congeners (Lees 2020).
Trend justification
The trend has not been quantified, but the population is in decline as a consequence of large-scale habitat loss, degradation and fragmentation (Lees 2020). The species has become locally extinct in remnants with an area of <2 km2 (ICMBio 2018).
A study projecting the impacts of infrastructure development on Amazonian birds predicted a 38% loss of habitat between 2003 and 2020 (Vale et al. 2008), which equates to 25% over ten years. Since 2017, tree cover within the range has been lost at a rate equivalent to 12% over ten years (Global Forest Watch 2022, using Hansen et al. [2013] data and methods disclosed therein). This value however does not account for forest degradation and fragmentation, which are known to have substantial negative impacts on the species (ICMBio 2018). The overall rate of habitat loss is therefore likely higher than this value, with population declines being significantly higher. Precautionarily, the rate of decline over the past ten years is placed in the band 20-29%, while declines are suspected to increase in the future to a rate equivalent to 30-49% over ten years.
This species occurs in east Amazonian Brazil, mainly between the rio Tapajós and rio Xingu in Pará and north Mato Grosso.
This species inhabits the undergrowth of lowland 'terra firme' forest, occasionally venturing into 'várzea' habitat (Lees 2020). It depends on primary forest and is highly sensitive to habitat degradation and fragmentation, and has become extinct in small, isolated fragments (ICMBio 2018). The minimum patch size to support a viable population was reported as 19 km2 (Lees and Peres 2010).
It is an obligate ant follower, requiring swarms of army ants, primarily Eciton burchelli, which flush the small arthropods that the species feeds upon. Pairs or families search through the forest early in the morning in order to locate the ants. Once located, the swarm is usually followed for the rest of the day. Nesting is thought to coincide with the onset of the rainy season in November (Lees 2020).
The species is suffering from widespread deforestation in Pará and Mato Grosso, which has increased markedly since the 1960s due to road building, ranching, smallholder agriculture, mining and hydroelectric development (Cleary 1991, Stotz et al. 1996). Deforestation is a particularly acute threat for this highly fragmentation-sensitive species (Lees and Peres 2010). It is believed that the species is able to cross unforested gaps of up to 700 m wide (ICMBio 2018). However, a population became extinct in a forest fragment of c.2 km2 within 17 years of becoming isolated, due to the extinction of Eciton burchelli swarms (Lees and Peres 2010, ICMBio 2018).
Conservation Actions Underway
The species is included in a multi-species action plan for Amazonian birds (ICMBio 2018). It is found in several protected areas across its range, including Juruena National Park (ICMBio 2018).
Conservation Actions Proposed
Survey to locate additional populations and accurately delimit the distribution range. Quantify the population size. Research the population structure. Research threats and their impacts, including the direct impact of forest loss and fragmentation on the species itself, as well as their indirect impact via the population dynamics of army ants. Monitor the population trend. Monitor rates of habitat loss.
Expand the protected area network to effectively protect key sites. Effectively manage protected areas, utilising emerging opportunities to finance protected area management with the joint aims of reducing carbon emissions and maximizing biodiversity conservation. Incentivise conservation on private lands through expanding market pressures for sound land management and preventing forest clearance on lands unsuitable for agriculture (Soares-Filho et al. 2006).
13.5-14.5cm, 27-30g. Large greyish-green periorbital patch (bare-eye) and with a fairly prominent crest. Male has head, including nape, to upper breast blackish-grey, yellowish-brown upperparts and dusky brown flanks and lower belly. Female has blackish head and throat and more extensive yellow-brown on rest of plumage. Similar spp. Harlequin Antbird R. berlepschi male is similar to female of R. gymnops, though has rufous breast patch and nape and grey neck side and underparts. Also the species is not known to overlap geographically. Voice A short series of about 2.8 seconds containing about 5 whistles, the first of which is longest and flat, the second of which is shortest and most downslurred after which the notes lengthen and flatten. Calls include a harsh "chirr".
Text account compilers
Hermes, C.
Contributors
Butchart, S., Ekstrom, J., Fisher, S., Harding, M., Sharpe, C.J. & Symes, A.
Recommended citation
BirdLife International (2024) Species factsheet: Bare-eyed Antbird Rhegmatorhina gymnops. Downloaded from
https://datazone.birdlife.org/species/factsheet/bare-eyed-antbird-rhegmatorhina-gymnops on 23/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 23/11/2024.