BirdAnalyst
Species · Montana · BBS 2026 Release · 1966–2025

Williamson's Sapsucker Population Trend in Montana

All statesForest birds

Williamson's Sapsucker in Montana has fallen sharply: down 63% on the route-weighted index since 1972.

-63%Since 1972TrendPercent 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 →
26Routes 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 →
42YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Williamson's Sapsucker 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 declinecomputed 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 →

Williamson's Sapsucker has fallen sharply in Montana: down 63% on the route-weighted index since 1972.

Williamson's Sapsucker Population Forecast in Montana

If the recent trend holds, Williamson's Sapsucker in Montana is projected to stay roughly flat through 2030, near 0.13 (95% range 0.00–0.28). A 5-year backtest shows a typical error of ±305.8%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2030TrendPercent 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 →
0.13Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.2895% 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 →
±305.8%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, Williamson's Sapsucker in Montana is projected to stay roughly flat through 2030, near 0.13 (95% range 0.00–0.28). A 5-year backtest shows a typical error of ±305.8%, with 100% of held-out values landing inside the 95% band.19692030
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 →
20260.130.000.28
20270.130.000.28
20280.130.000.28
20290.130.000.28
20300.130.000.28

Williamson's Sapsucker Survey Routes in Montana

Routes recording Williamson's Sapsucker 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 →
Greenough720041999
Greenoagh 2720112005
St Regis319821982
Victor220011994
Clinton219721972
Swan Lake220162015
Noxon220232001
Libby Dam119811981
Threemile Wa120132004
Cramer Creek120192000
Elevation Mt120251996
Pryor Mtn.120122002
Arlee120191969
Woodman120211990
Inside Road120152014
Sula120241986
Reed Point120092009
Whitefish Lake120222017
Red Rock120061996
Skalkho-Rye120162000
Greenoagh 3120252014
Ninemile120222003
Fish Creek120242024
Skalkaho119961992
Hebgen Lake120242017

Williamson's Sapsucker Population Trend in Other States

arizonacaliforniacoloradoidahonevadanew-mexicooregonutahwashingtonwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.