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Species · Washington · BBS 2025 Release · 1966–2024

Western Gull Population Trend in Washington

All statesWetland birds

Western Gull in Washington has collapsed: down 94% on the route-weighted index since 1971.

-94%Since 1971TrendPercent 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 →
38YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Western Gull 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 →

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 →

Western Gull has collapsed in Washington: down 94% on the route-weighted index since 1971.

Western Gull Population Forecast in Washington

If the recent trend holds, Western Gull in Washington is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–3.6). A 5-year backtest shows a typical error of ±1589%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.00Projected 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 →
0.00–3.695% 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 →
±1589%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, Western Gull in Washington is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–3.6). A 5-year backtest shows a typical error of ±1589%, 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 →
20250.000.003.6
20260.000.003.6
20270.000.003.6
20280.000.003.6
20290.000.003.6

Western Gull Survey Routes in Washington

Routes recording Western Gull 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 →
Taholah4720221969
Warm Beach119931989
Ilwaco120231975
Bunker Hill119891989
Raymond120132008
Raymond 2120242024

Western Gull Population Trend in Other States

californiaoregon

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