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Species · Colorado · BBS 2025 Release · 1966–2024

Williamson's Sapsucker Population Trend in Colorado

All statesForest birds

Williamson's Sapsucker in Colorado has surged: up 164% on the route-weighted index since 1972.

+164%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 →
49Routes 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 Williamson's Sapsucker Trends in ColoradoNotable 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 Colorado: up 164% on the route-weighted index since 1972.

Williamson's Sapsucker Population Forecast in Colorado

If the recent trend holds, Williamson's Sapsucker in Colorado is projected to rise about 35% by 2029 — from 0.15 in 2024 to a central estimate of 0.21 (95% range 0.00–0.44). A 5-year backtest shows a typical error of ±51.3%, with 100% of held-out values landing inside the 95% band.

+35%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 →
0.21Projected 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 →
0.00–0.4495% 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 →
±51.3%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, Williamson's Sapsucker in Colorado is projected to rise about 35% by 2029 — from 0.15 in 2024 to a central estimate of 0.21 (95% range 0.00–0.44). A 5-year backtest shows a typical error of ±51.3%, with 100% of held-out values landing inside the 95% band.19692029
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 →
20250.210.000.43
20260.210.000.43
20270.210.000.44
20280.210.000.44
20290.210.000.44

Williamson's Sapsucker Survey Routes in Colorado

Routes recording Williamson's Sapsucker in Colorado.
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 →
Powderhorn620232000
Pinos Creek519891988
Flattops520161993
Comanche Pk320221999
Como320162016
Marshall Pas320142002
Deadman Rd.320242012
Wet Mtns.320181995
Cochetopa Pass320072005
Haycamp Mesa320242000
Pagosa Spgs219821975
Lost Lake219991999
Buffalo Park220231993
Fox Creek220111993
Stillwater Pass220092007
Cokedale220032003
Ludlow220112011
Blackhead Pk220141994
Yampa119721972
Mount Evans120172000
Buford119941994
Cheesman Lk120191969
Delta120181974
Colona120121973
Parlin120081972

Williamson's Sapsucker Population Trend in Other States

arizonacaliforniaidahomontananevadanew-mexicooregonutahwashingtonwyoming

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