BirdAnalyst
Species · Washington · BBS 2025 Release · 1966–2024

Fox Sparrow Population Trend in Washington

All statesGeneralists

Fox Sparrow in Washington has held roughly steady: up 10% on the route-weighted index since 1970.

+10%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 →
31Routes 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 →
54YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Fox Sparrow 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 →

No notable trend signals for Fox Sparrow in Washington. See the full index history below.

Fox Sparrow Population Forecast in Washington

If the recent trend holds, Fox Sparrow in Washington is projected to fall about 48% by 2029 — from 0.26 in 2024 to a central estimate of 0.14 (95% range 0.00–0.29). A 5-year backtest shows a typical error of ±43.9%, with 100% of held-out values landing inside the 95% band.

-48%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 →
0.14Projected 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 →
0.00–0.2995% 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 →
±43.9%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, Fox Sparrow in Washington is projected to fall about 48% by 2029 — from 0.26 in 2024 to a central estimate of 0.14 (95% range 0.00–0.29). A 5-year backtest shows a typical error of ±43.9%, with 100% 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 →
20250.140.000.29
20260.140.000.29
20270.140.000.29
20280.140.000.29
20290.140.000.29

Fox Sparrow Survey Routes in Washington

Routes recording Fox Sparrow 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 →
Spring Lake520241982
Mt Rainier520181992
E. Mt. Adams420241995
Cloverland420241993
Nighthawk319921992
Northport319971997
Keller220061968
Camas219771977
Ronald220232013
Mazama219941993
Greenwater220232015
Ozette120032003
Port Angeles119741974
Cascade Riv120032000
L Pend O Nwr120172017
Cougar119901990
Rimrock120101982
Asotin120012001
Snowden120191982
Sullivan Lake 2120242006
Glacier120241981
Winthrop119891989
Cusick120221993
Packwood120011981
Carlton120001998

Fox Sparrow Population Trend in Other States

alaskacaliforniacoloradoidahomainemontananevadaoregonutahwyoming

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