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

Bobolink Population Trend in Washington

All statesGrassland birds

Bobolink in Washington has edged up: up 11% on the route-weighted index since 1990.

+11%Since 1990TrendPercent 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 →
6Routes 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 →
25YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Bobolink 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 Bobolink in Washington. See the full index history below.

Bobolink Population Forecast in Washington

If the recent trend holds, Bobolink in Washington is projected to stay roughly flat through 2028, near 0.08 (95% range 0.00–0.19). A 5-year backtest shows a typical error of ±102.2%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2028TrendPercent 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 →
0.08Projected 2028 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.1995% 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 →
±102.2%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, Bobolink in Washington is projected to stay roughly flat through 2028, near 0.08 (95% range 0.00–0.19). A 5-year backtest shows a typical error of ±102.2%, with 100% of held-out values landing inside the 95% band.19782028
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 →
20240.070.000.19
20250.070.000.19
20260.080.000.19
20270.080.000.19
20280.080.000.19

Bobolink Survey Routes in Washington

Routes recording Bobolink 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 →
Nighthawk920161993
Laurier319951995
Cusick120232016
Omak Creek119981998
Chewelah119941978
Tonasket120131991

Bobolink Population Trend in Other States

californiacoloradoconnecticutidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooregonpennsylvaniarhode-islandsouth-dakotautahvermontvirginiawest-virginiawisconsinwyoming

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