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Species · Washington · BBS 2025 Release · 1966–2024

Glaucous-winged Gull Population Trend in Washington

All statesWetland birds

Glaucous-winged Gull in Washington has fallen sharply: down 71% on the route-weighted index since 1970.

-71%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 →
20Routes 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 →
56YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Glaucous-winged 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 →

Glaucous-winged Gull has fallen sharply in Washington: down 71% on the route-weighted index since 1970.

Glaucous-winged Gull Population Forecast in Washington

If the recent trend holds, Glaucous-winged Gull in Washington is projected to fall about 100% by 2029 — from 1.4 in 2024 to a central estimate of 0.00 (95% range 0.00–7.5). A 5-year backtest shows a typical error of ±80.4%, with 100% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–7.595% 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 →
±80.4%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, Glaucous-winged Gull in Washington is projected to fall about 100% by 2029 — from 1.4 in 2024 to a central estimate of 0.00 (95% range 0.00–7.5). A 5-year backtest shows a typical error of ±80.4%, 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 →
20250.050.007.6
20260.000.007.5
20270.000.007.5
20280.000.007.5
20290.000.007.5

Glaucous-winged Gull Survey Routes in Washington

Routes recording Glaucous-winged 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 →
Port Angeles6220241970
Warm Beach 21420212018
Taholah1220221969
Warm Beach1120171968
Mukilteo1120241993
Bay View620171993
No Cascades419961996
Ilwaco320221975
Ozette220221971
Issaquah219731969
Deception220181992
Vashon Is.220241995
Mcchord220151996
Raymond220211993
Kamilche120141997
Bunker Hill119891987
Camas120052005
Raymond 2120242022
Everett120241977
South Elma120241994

Glaucous-winged Gull Population Trend in Other States

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