BirdAnalyst
Species · Montana · BBS 2025 Release · 1966–2024

Pacific Wren Population Trend in Montana

All statesForest birds

Pacific Wren in Montana has surged: up 463% on the route-weighted index since 1971.

+463%Since 1971TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
23Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
51YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Pacific Wren Trends in MontanaNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

long arc increasecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Pacific Wren has surged in Montana: up 463% on the route-weighted index since 1971.

Pacific Wren Population Forecast in Montana

If the recent trend holds, Pacific Wren in Montana is projected to rise about 68% by 2029 — from 0.39 in 2024 to a central estimate of 0.65 (95% range 0.14–1.2). A 5-year backtest shows a typical error of ±68.3%, with 100% of held-out values landing inside the 95% band.

+68%Change by 2029TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
0.65Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.14–1.295% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±68.3%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Pacific Wren in Montana is projected to rise about 68% by 2029 — from 0.39 in 2024 to a central estimate of 0.65 (95% range 0.14–1.2). A 5-year backtest shows a typical error of ±68.3%, with 100% of held-out values landing inside the 95% band.19682029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
20250.610.101.1
20260.630.111.1
20270.630.121.2
20280.640.131.2
20290.650.141.2

Pacific Wren Survey Routes in Montana

Routes recording Pacific Wren in Montana.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
Whitefish Lake1220242016
Skalkaho1219981992
Swan Lake620242015
Libby Dam420001988
Threemile Wa320241993
St Regis320241983
Arlee320241968
Skalkho-Rye320221999
Ninemile320221998
Cramer Creek220112005
Thompson Riv220241993
Painted Rock220191993
Noxon220221995
Kalispell120022002
Logan Pass120241988
Greenough120031996
Elevation Mt120222021
Woodman120241968
Clinton120081987
Inside Road120241990
Sula120121986
Greenoagh 2120082008
Fish Creek120241998

Pacific Wren Population Trend in Other States

alaskacaliforniaidahonevadaoregonsouth-dakotawashington

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.