Data Zone
Justification of Red List category
This species is classified as Vulnerable because it is thought to have a very small population. It is confined to a small range, which is currently not under imminent threat, but may be increasingly threatened in the near future by potential human developments and the impacts of climate change.
Population justification
The population size has not been quantified directly. Based on population density estimates of two closely related species with similar body size, similar habitat requirements and a similar altitudinal range, Myiothlypis nigrocristata and Myiothlypis luteoviridis, of 10-100 individuals/km2 in Andean forests in Ecuador (per Renjifo et al. 2016), and assuming that this species occurs at a similar density throughout suitable habitat (which is estimated at up to 100 km2; Wege 1996), the total population is estimated at 1,000-10,000 individuals. This roughly equates to 650-6,500 mature individuals.
The subpopulation structure has not been formally assessed, but it is tentatively assumed that there are two disjunct subpopulations on Cerro Pirre and on Cerro Tacarcuna. Under the assumption that the total population size is closer to the lower end of the estimate, both subpopulations may be very small.
Trend justification
The population is currently suspected to be stable in the absence of evidence for any declines or substantial threats.
Basileuterus ignotus is confined to a very small range, estimated at c.180 km2, on the Serranía de Pirre and Cerro Tacarcuna in Darién, Panama, and north-west Chocó, Colombia (Wetmore et al. 1984; Hilty and Brown 1986; Ridgely and Gwynne 1989; Wege 1996). Within this range, the species is thought to occupy an area of less than 100 km2 of suitable habitat (Wege 1996). It is generally uncommon (Ridgely and Gwynne 1989), but was found to be fairly common above 1,400 m on Alturas de Nique (above Cana) in 1985 (Robbins et al. 1985). On Cerro Tacarcuna, the species is known from five specimens collected at 1,650 m in 1975 (Wetmore et al. 1984).
The species inhabits the lower growth of humid elfin forest, where it is reported to be most common above 1,400 m on the Serranía de Pirre (Robbins et al. 1985). The breeding behaviour is virtually unknown, but recently fledged young have been seen in July (Robbins et al. 1985).
Its small range puts it at inherent risk from any habitat loss or degradation. Habitat in the region is being cleared and degraded for mining, agriculture and cultivation of coca (Wege 1996), but probably not yet within the altitudinal range of this species. Completion of the Pan-American highway link through Darién could lead to severe, long-term damage of forests in Darién and the adjacent Chocó (Alvarez-Cordero et al. 1994, Wege 1996). As the species inhabits a very small area near the top of two mountain ranges, it may be vulnerable to global climate change and related range shifts (G. Angehr in litt. 2020).
Conservation Actions Underway
The Panamanian part (i.e. the majority) of its range lies entirely within Darién National Park (Wege 1996). However, legal protection has not halted habitat loss at lower altitudes (Wege 1996). In Colombia, it may be found to occur within Katíos National Park (Renjifo et al. 2002).
13.5 cm. Distinctively marked warbler. Dull olive-green upperparts, creamy-yellow underparts, greenish-yellow supercilium bordered by black above, rufous crown, dusky olive ear-coverts. Voice Song is undescribed. Call a penetrating tseeut.
Text account compilers
Hermes, C.
Contributors
Angehr, G., Bird, J., Butchart, S., Gilroy, J., Isherwood, I., Pople, R., Sharpe, C.J. & Stuart, T.
Recommended citation
BirdLife International (2024) Species factsheet: Pirre Warbler Basileuterus ignotus. Downloaded from
https://datazone.birdlife.org/species/factsheet/pirre-warbler-basileuterus-ignotus 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.