Data Zone
Justification of Red List category
This species has a very large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km² combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Population justification
The global population size has not been quantified, but the species is described as 'uncommon and patchily distributed' (Stotz et al. 1996; see also Benham et al. 2011). Assuming that the species occurs at the same density as a congener (S. desmursii in Argentina: 5-10 individuals/km2; Santini et al. 2018) and further assuming that only 10% of the mapped range are occupied to account for the species's rarity, the population may number 74,000-148,000 individuals. This roughly equates to 50,000-100,000 mature individuals.
The subpopulation structure has not been investigated, but based on the species's disjunct range it is thought that it forms five subpopulations, the largest of which may number c.20,000-40,000 mature individuals.
Trend justification
This species is suspected to be declining owing to the loss and degradation of its Polylepis habitat (J. Cahill in litt. 2020). Over ten years, about 2% of tree cover is lost within the range (Global Forest Watch 2021, using Hansen et al. [2013] data and methods disclosed therein). Therefore, population declines are unlikely to exceed 10% over ten years.
The species occurs in a disjunct range in Peru (from the Cordillera Blanca in Ancash and north Lima, on the east slope of the Andes in Cuzco and Apurímac), west Bolivia (from La Paz south to Potosí and Tarija) (Ridgely and Tudor 1994, Maynard and Waterton 1998) and north-west Argentina (Jujuy and Salta) (Mazar Barnett et al. 1998, Pearman 2001).
In the semi-humid north of its range, it exclusively inhabits highly fragmented Polylepis woodland (Fjeldså and Kessler 1996), and in some localities it appears to be strongly tied to Polylepis groves (Pearman 2001). It may show a preference for the interior of forest fragments, shunning the edges particularly during the breeding season (Cahill and Matthysen 2007). In the more arid south, it also occurs in shrubbery and on steep rocky slopes with bunchgrass and low bushes (Fjeldså and Krabbe 1990, Ridgely and Tudor 1994, Fjeldså and Kessler 1996, Mazar Barnett et al. 1998). It occurs at 2,850-4,600 m (Fjeldså and Krabbe 1990, Ridgely and Tudor 1994, Mazar Barnett et al. 1998), occasionally to 5,200 m (Parker et al. 1996), and remains at high altitude even during snowstorms (Fjeldså and Krabbe 1990).
The main threats are heavy grazing by livestock and uncontrolled use of fire, which combine to prevent Polylepis regeneration, especially where cutting for timber, firewood and charcoal occurs (Fjeldså and Kessler 1996). The change from camelid to sheep and cattle farming, and erosion and soil degradation caused by agricultural intensification and afforestation (especially with Eucalyptus) are contributory factors (Fjeldså and Kessler 1996).
Conservation Actions Underway
No targeted actions are known for this species.
Conservation Actions Proposed
Conduct surveys to assess the species's total population size. Monitor population trends through regular surveys. Monitor rates of habitat loss and degradation.
Ensure that remaining tracts of Polylepis forest habitat within the range receive adequate protection, particularly in areas where connectivity between habitat patches can be maintained.
Text account compilers
Hermes, C.
Contributors
Butchart, S., Cahill, J., Gilroy, J. & Sharpe, C.J.
Recommended citation
BirdLife International (2024) Species factsheet: Tawny Tit-spinetail Sylviorthorhynchus yanacensis. Downloaded from
https://datazone.birdlife.org/species/factsheet/tawny-tit-spinetail-sylviorthorhynchus-yanacensis on 22/11/2024.
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 22/11/2024.