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Species · BCR 34 · BBS 2026 Release · 1966–2025

Williamson's Sapsucker In Sierra Madre Occidental

All regionsSierra Madre OccidentalForest birds

Williamson's Sapsucker in Sierra Madre Occidental has fallen sharply: down 53% on the route-weighted index since 1985.

-53%Since 1985TrendPercent 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 →
7Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
24YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable 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 Sierra Madre Occidental: down 53% on the route-weighted index since 1985.

Williamson's Sapsucker In Sierra Madre Occidental Population Forecast

If the recent trend holds, Williamson's Sapsucker in Sierra Madre Occidental is projected to stay roughly flat through 2030, near 0.07 (95% range 0.00–0.26). A 5-year backtest shows a typical error of ±92.1%, with 100% of held-out values landing inside the 95% band.

+0%Change 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 →
0.07Projected 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 →
0.00–0.2695% 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 →
±92.1%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 Sierra Madre Occidental is projected to stay roughly flat through 2030, near 0.07 (95% range 0.00–0.26). A 5-year backtest shows a typical error of ±92.1%, with 100% of held-out values landing inside the 95% band.19742030
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 →
20260.080.000.26
20270.080.000.26
20280.080.000.26
20290.080.000.26
20300.070.000.26

Routes In Sierra Madre Occidental

Routes recording Williamson's Sapsucker in Sierra Madre Occidental.
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 →
AlpineARIZONA22025
SprucedaleARIZONA22019
FlagstaffARIZONA11994
BlueARIZONA11985
Forest LakesARIZONA11994
PinetopARIZONA12022
Happy JackARIZONA11977

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