BirdAnalyst
Species · BBS 2025 Release · 1966–2024

Williamson's Sapsucker

PicidaeForest birdsSphyrapicus thyroideus

Williamson's Sapsucker has surged: up 22× on the route-weighted index since 1970.

22×Since 1970TrendPercent 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 →
237RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
56Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

About the Williamson's Sapsucker

The Williamson's Sapsucker (Sphyrapicus thyroideus) is a North American member of the Woodpeckers (Picidae). In this analysis it is grouped with the forest birds.

Size
6–19.5 in long (15–50 cm) — a chisel-billed climber (typical for the family)
Habitat
Woodlands and forest edges, including wooded suburbs and parks.
Diet
Insects and spiders gleaned from foliage and bark, with seeds and berries in season.
Range
Recorded on 237 Breeding Bird Survey routes across 11 states, most concentrated in the Northern Rockies.
Family
Picidae · Forest birds

Notable Williamson's Sapsucker TrendsNotable 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. See the full index history below.

Williamson's Sapsucker Population Forecast

If the recent trend holds, Williamson's Sapsucker is projected to rise about 13% by 2029 — from 0.05 in 2024 to a central estimate of 0.06 (95% range 0.05–0.08). A 5-year backtest shows a typical error of ±21.5%, with 80% of held-out values landing inside the 95% band.

+13%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 →
0.06Projected 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 →
0.05–0.0895% 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 →
±21.5%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 is projected to rise about 13% by 2029 — from 0.05 in 2024 to a central estimate of 0.06 (95% range 0.05–0.08). A 5-year backtest shows a typical error of ±21.5%, with 80% 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 →
20250.060.040.07
20260.060.040.07
20270.060.040.07
20280.060.040.07
20290.060.050.08

Where the Williamson's Sapsucker Is Detected

BBS routes recording Williamson's Sapsucker, sized by most recent count.

Williamson's Sapsucker Population Trend by State

Williamson's Sapsucker population trend by state.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Arizona+162%198510
California+40%197532
Colorado+164%197249
Idaho-11%198918
Montana-43%197226
Nevadainsufficient datan/a2
New Mexico-21%198411
Oregon+314%197144
Utah-7%198818
Washington+476%198215
Wyoming-52%198712

Williamson's Sapsucker Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Williamson's Sapsucker population trend by Bird Conservation Region.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Northern Pacific Rainforest-34%19765
Great Basin+201%197138
Northern Rockies+376%197283
Sierra Nevada+35%197518
Southern Rockies / Colorado Plateau+496%197280
Sierra Madre Occidental-41%19857

Williamson's Sapsucker Conservation Status

Our route-weighted index shows it up about 2089% since 1970.

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.