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Species · Idaho · BBS 2025 Release · 1966–2024

Williamson's Sapsucker Population Trend in Idaho

All statesForest birds

Williamson's Sapsucker in Idaho has edged down: down 11% on the route-weighted index since 1989.

-11%Since 1989TrendPercent 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 →
18Routes 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 →
27YearsYears 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 IdahoNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Williamson's Sapsucker in Idaho. See the full index history below.

Williamson's Sapsucker Population Forecast in Idaho

If the recent trend holds, Williamson's Sapsucker in Idaho is projected to stay roughly flat through 2029, near 0.07 (95% range 0.00–0.16). A 5-year backtest shows a typical error of ±36.1%, with 80% of held-out values landing inside the 95% band.

n/aChange 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 →
0.07Projected 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 →
0.00–0.1695% 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 →
±36.1%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 Idaho is projected to stay roughly flat through 2029, near 0.07 (95% range 0.00–0.16). A 5-year backtest shows a typical error of ±36.1%, with 80% of held-out values landing inside the 95% band.19852029
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 →
20250.070.000.16
20260.070.000.16
20270.070.000.16
20280.070.000.16
20290.070.000.16

Williamson's Sapsucker Survey Routes in Idaho

Routes recording Williamson's Sapsucker in Idaho.
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 →
Pierce420032003
Sawtooth City 2320192016
Avery219911991
Lolo Pass220072007
Cabarton220032003
Burgdorf220001989
Alturas219851985
Sunbeam220162016
Sawtooth Cty220132011
Coolin220182018
Grangeville120161986
Golden120142014
Cape Horn120112011
Salmon River120091997
Cobalt120152001
Magic Mtn120242015
Featherville119921992
Baldy Mountain120162013

Williamson's Sapsucker Population Trend in Other States

arizonacaliforniacoloradomontananevadanew-mexicooregonutahwashingtonwyoming

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