Pacific Wren Troglodytes pacificus


Justification of Red List Category
This species has an extremely 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 extremely 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 is inferred to number 7,500,000 mature individuals (Partners in Flight 2019).

Trend justification

The species has been undergoing a moderate decline at an average rate of 0.6% per year between 1970 and 2017 (Partners in Flight 2019). Short-term trends from the North American Breeding Bird Survey (BBS) suggest increasingly negative population trajectories and a half-life of 15 years (Pardieck et al. 2018). BBS data are however not considered representative for this species and moreover, the population is known to fluctuate considerably depending on climatic conditions in winter (Toews and Irwin 2020; see also trends from Pardieck et al. 2018). Therefore, it is here assumed that the overall population declines are closer to the long-term trend reported by Partners in Flight (2019), amounting to 6% over ten years.


Text account compilers
Hermes, C.

Butchart, S., Ekstrom, J., Khwaja, N., Miller, E. & Symes, A.

Recommended citation
BirdLife International (2022) Species factsheet: Troglodytes pacificus. Downloaded from on 03/07/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from on 03/07/2022.