Wedge-tailed Hillstar Oreotrochilus adela


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 may be moderately small to large, but it is not believed to 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 population size has not been quantified directly. A congener (O. leucopleurus in Argentina) occurs at a density of 4-12 individuals/km2 (Santini et al. 2018); however this is likely not representative for O. adela, whose density is considered not to exceed 4 individuals/km2 (S. K. Herzog in litt. 2021). Assuming that only 10% of the mapped range is occupied to account for the species's rarity (i.e. 3,800 km2), the species may number at most 15,200 individuals, which roughly equates to 10,000 mature individuals. The population size is consequently here placed in the band 2,500-9,999 mature individuals.

Assuming that the species forms three separate subpopulations within its range, that 10% of the range is occupied at a density of up to 4 individuals/km2, the largest subpopulation (occupying an area of 1,700 km2, based on the area of the range polygon) may number up to 4,500 mature individuals.

Trend justification
The population trend has not been quantified. The species is able to tolerate substantial habitat degradation (Fjeldså and Kirwan 2020). However, due to the high anthropogenic pressure on natural habitat within the range, the species is precautionarily suspected to decline slowly owing to habitat degradation and destruction.

Distribution and population

Oreotrochilus adela has a restricted range in the high Andes from Cochabamba or probably southern La Paz in the north through Potosí and Chuquisaca in south-west Bolivia to Jujuy in northern Argentina (Armonía 1995; Fjeldså and Kirwan 2020).


It inhabits arid and semi-arid montane scrub, Polylepis forest and disturbed habitats at 2,550-4,000 m (Fjeldså and Krabbe 1990; Armonía 1995; Parker et al. 1996; Fjeldså and Kirwan 2020).


The main threats are heavy grazing by livestock and the 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, erosion and soil degradation caused by agricultural intensification and afforestation, especially where exotic tree species (e.g. Eucalyptus) are planted (Fjeldså and Kessler 1996), are contributory factors.

Conservation actions

Conservation Actions Underway
CITES Appendix II.

Conservation Actions Proposed
Establish adequate protected areas to protect the species's core range. Attempt to obtain an accurate estimate of its population size and trends. Monitor population at strongholds and search for the species in potentially suitable habitat at new sites. Study its ecology and its ability to persist in degraded and fragmented habitats. Quantify the extent of habitat loss


Text account compilers
Hermes, C.

Benstead, P., Capper, D., Herzog, S.K., Sharpe, C.J. & Symes, A.

Recommended citation
BirdLife International (2023) Species factsheet: Oreotrochilus adela. Downloaded from on 05/02/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from on 05/02/2023.