LC
Pacific Wren Troglodytes pacificus



Taxonomy

Taxonomic note

Troglodytes troglodytes, T. pacificus and T. hiemalis (del Hoyo and Collar 2016) were previously lumped as T. troglodytes following AERC TAC (2003), AOU (1998 & supplements), Cramp et al. (1977-1994), Sibley & Monroe (1990, 1993) and Stotz et al. (1996).

Taxonomic source(s)
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A., Fishpool, L.D.C., Boesman, P. and Kirwan, G.M. 2016. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 2: Passerines. Lynx Edicions and BirdLife International, Barcelona, Spain and Cambridge, UK.

IUCN Red list criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
- - -

Red List history
Year Category Criteria
2021 Least Concern
2016 Least Concern
Species attributes

Migratory status full migrant Forest dependency Medium
Land mass type Average mass 9 g
Distribution

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 9,680,000 medium
Extent of Occurrence non-breeding (km2) 9,920,000 medium
Number of locations -
Severely Fragmented -
Population and trend
Value Data quality Derivation Year of estimate
No. of mature individuals 7500000 poor inferred 2019
Population trend Decreasing inferred -
Decline (3 years/1 generation past) - - -
Decline (5 years/1 generation past) - - -
Decline (10 years/1 generation past) - - -
Decline (10 years/3 generation future) - - -
Decline (10 years/3 generation past and future) - - -
Number of subpopulations - - -
Percentage in largest subpopulation - - -

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.


Country/territory distribution
Country/Territory Occurrence status Presence Resident Breeding Non-breeding Passage
Canada N Extant Yes Yes
Mexico N Extant Yes
USA N Extant Yes Yes Yes Yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Artificial/Terrestrial Rural Gardens suitable breeding
Artificial/Terrestrial Rural Gardens suitable non-breeding
Artificial/Terrestrial Urban Areas suitable breeding
Artificial/Terrestrial Urban Areas suitable non-breeding
Forest Boreal major breeding
Forest Subtropical/Tropical Moist Lowland suitable breeding
Forest Subtropical/Tropical Moist Lowland suitable non-breeding
Forest Temperate major breeding
Forest Temperate major non-breeding
Shrubland Boreal suitable breeding
Shrubland Boreal suitable non-breeding
Shrubland Temperate suitable breeding
Shrubland Temperate suitable non-breeding
Altitude   Occasional altitudinal limits  

Utilisation
Purpose Primary form used Life stage used Source Scale Level Timing
Food - human - - Non-trivial Recent
Pets/display animals, horticulture - - International Non-trivial Recent

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