NatureCounts - The State of Canada's Birds

Summary

National

Trend

Little Change

Confidence: Medium

Goal

Below Goal Range

The Pacific Wren was formally recognised as separate from Winter Wren in 2010 (Toews and Irwin, 2008, Chesser et al., 2010). It occupies moist coniferous forests from southwestern Yukon and coastal British Columbia to the Alberta foothills east of the Rocky Mountains. Most Canadian breeders are year-round residents, although there is some retraction from the eastern edges of the breeding range in winter, and the majority of those breeding in Alaska migrate to or through Canada. Approximately 2.8 million individuals breed in Canada, representing 37% of the global population and a moderate degree of responsibility for Canada. Adding the migrants from Alaska boosts the total to as much as 5.3 million (71%), corresponding to high responsibility.

The Canadian population of Pacific Wren is currently at a level similar to that in the early 1970s based on the Breeding Bird Survey, but confidence in the assessment is only medium because the Christmas Bird Count differs by indicating a moderate increase. However, the population has declined enough from its long-term average level that it is currently below its goal range.

Migration Strategy

Short-distance

Resident

Canadian Responsibility

High

Population Estimates

Breeding 2,800,000

Annual 5,300,000

Global 7,500,000

Population Trends

The Canadian population of Pacific Wren is best monitored by the Breeding Bird Survey (BBS), which samples a moderate proportion of the breeding range, is well-suited to the species, and has high precision. The national trend shows considerable inter-annual fluctuations, but overall a strong increase throughout the 1970s, a slight decline in the late 1980s, a peak around 2000, and a subsequent decline to late 1970s levels. At a regional scale, the smaller interior population spanning interior British Columbia and western Alberta has experienced a large long-term increase, offsetting the slight decrease along the Pacific coast. The Canadian population is also monitored by the Christmas Bird Count (CBC), which likewise reflects notable inter-annual fluctuations in numbers, but has lower precision, and overall shows a simpler trend over time, increasing gradually from 1970 to around 2006, and then declining slightly since then.

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Population Goals

The goal for Pacific Wren is to remain at or above its average population level from 1970 to 2022, based on the Breeding Bird Survey. Recent data show that the population is below its goal range.

National

Canada

Population Goal

Be at or above long-term average

Population status relative to goal

Below Goal Range

Goal is based on Breeding Bird Survey

Designations

Designation	Geographic Area	Status	CITATION
IUCN	Global	Least Concern
Wild Species	Canada	Secure

References

Chesser, R.T., R.C. Banks, F.K. Barker, C. Cicero, J.L. Dunn, W.W. Kratter, I.J. Lovette, P.C. Rasmussen, J.V. Remsen, Jr., J.D. Rising, D.F. Stotz and K. Winker. 2010. Fifty-first supplement to the American Ornithologists’ Union check-list of North American birds. Auk 127:726−744. http://www.aou.org/checklist/suppl/AOU_checklist_suppl_51.pdf.
Toews, D.P.L. and D.E. Irwin. 2008. Cryptic speciation in a Holarctic passerine revealed by genetic and bioacoustic analyses. Molecular Ecology 17:2691-2705.