Justification of Red List Category
It is suspected that this species will undergo an extremely rapid decline over the next three generations, having already potentially experienced a rapid decline over the last three generations such that the population size is suspected to be extremely small. The species's habitat continues to be extensively cleared and heavily degraded in its very small range, in which it is known from only one location. Therefore, this species is listed as Critically Endangered.
The species's population size has not been formally estimated and, in the absence of sufficient data, it is preliminarily estimated to number 50-249 mature individuals; however detailed research is urgently required. This estimate equates to 75-379 individuals in total, rounded here to 70-400 individuals.
The species's population is suspected to have undergone a very rapid decline of more than 70% over the last 10 years (Fundación ProAves de Colombia 2011) owing to extensive and severe habitat loss and degradation caused by deforestation, extensive burning and overgrazing. Given the severity of threats, this decline is expected to further accelerate in the future (Fundación ProAves de Colombia 2011).
Troglodytes monticola is endemic to the Sierra Nevada de Santa Marta, Colombia, where it is known from collections made in 1922, one record in the upper río Frío Valley at 3,600 m, where a pair was observed and tape-recorded in a small montane forest patch (c. 2 ha) amidst heavily burned and overgrazed páramo (R. Strewe in litt. 2003, Strewe & Navarro 2004), and 17 individuals located in a targeted search in 2011 (Luna and Quevedo 2012). Searches on the southern slopes and at the only other intact forest patch in the area failed to locate the species (R. Strewe in litt. 2003, Fundación ProAves de Colombia 2011), however in December 2011 the species was photographed for the first time and a total of 17 individuals were observed in three days along a 3 km stretch (Luna and Quevedo 2012). Several pairs of the species were sighted recently during fire surveys in the Parque Nacional Natural Sierra Nevada de Santa Marta (Rojas and Vasquez 2015). The paucity of records may partly reflect the fact that the species is not found in the only area of the Santa Marta massif regularly visited (Ridgely and Tudor 1989).
The species is reportedly found in low, thick shrubbery at the timberline and in sheltered spots high in the páramo zone, from 3,200 to 4,800 m (Ridgely and Tudor 1989, Kroodsma et al. 2015). It may actually be restricted to the timberline ecotone, rather than being a páramo specialist (Fundación ProAves de Colombia 2011).
There is a long history of severe deforestation and degradation of this species's páramo and timberline habitat (Kroodsma et al. 2015). Less than 15% of the original forest cover remains within the massif, and despite substantive protection status on paper, in reality extremely high rates of habitat loss continue owing to human colonisation and cultivation. In some areas deforestation has reached the species's elevation range (O. Cortes in litt. 2011) and streamside vegetation is unsustainably cut for firewood in some places (N. Krabbe in litt. 2010). The wren's habitat within Río Frío valley is extremely isolated, owing to burning and overgrazing, and more information is required concerning the habitat condition of other páramo and high montane forests elsewhere on the massif (Strewe and Navarro 2004).
Conservation and Research Actions Underway
The species's range lies within indigenous reserves and some protection may be provided by the Sierra Nevada de Santa Marta National Park. Further efforts to search for the species on the most intact western slopes were being pursued in early 2011 (Fundación ProAves de Colombia 2011).
Text account compilers
Harding, M., Gilroy, J., Sharpe, C.J., Symes, A., Taylor, J., Hermes, C., Wright, L
Krabbe, N., Cortés, O., Strewe, R.
BirdLife International (2020) Species factsheet: Troglodytes monticola. Downloaded from http://www.birdlife.org on 10/07/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 10/07/2020.