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Species · Washington · BBS 2025 Release · 1966–2024

Williamson's Sapsucker Population Trend in Washington

All statesForest birds

Williamson's Sapsucker in Washington has surged: up 476% on the route-weighted index since 1982.

+476%Since 1982TrendPercent 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 →
15Routes 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 WashingtonNotable 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 →

Williamson's Sapsucker has surged in Washington: up 476% on the route-weighted index since 1982.

Williamson's Sapsucker Population Forecast in Washington

If the recent trend holds, Williamson's Sapsucker in Washington is projected to fall about 38% by 2029 — from 0.56 in 2024 to a central estimate of 0.35 (95% range 0.20–0.50). A 5-year backtest shows a typical error of ±40.1%, with 60% of held-out values landing inside the 95% band.

-38%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 →
0.35Projected 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 →
0.20–0.5095% 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 →
±40.1%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 Washington is projected to fall about 38% by 2029 — from 0.56 in 2024 to a central estimate of 0.35 (95% range 0.20–0.50). A 5-year backtest shows a typical error of ±40.1%, with 60% of held-out values landing inside the 95% band.19802029
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 →
20250.320.170.47
20260.330.180.48
20270.340.180.49
20280.340.190.49
20290.350.200.50

Williamson's Sapsucker Survey Routes in Washington

Routes recording Williamson's Sapsucker in Washington.
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 →
Omak Creek920241996
Spring Lake620241985
Cloverland620241997
Carlton520221995
Blewett Pass520241992
E. Mt. Adams420241997
Ronald120241991
Mazama120012001
Twisp120052005
Laurier120162004
L. Wenatchee120021994
Rimrock120241980
Curlew119921992
Winthrop119831983
Twin Lakes119871987

Williamson's Sapsucker Population Trend in Other States

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