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

Long-billed Curlew Population Trend in Washington

All statesShorebirds

Long-billed Curlew in Washington has collapsed: down 85% on the route-weighted index since 1976.

-85%Since 1976TrendPercent 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 →
24Routes 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 →
49YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Long-billed Curlew 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 →

Long-billed Curlew has collapsed in Washington: down 85% on the route-weighted index since 1976.

Long-billed Curlew Population Forecast in Washington

If the recent trend holds, Long-billed Curlew in Washington is projected to stay roughly flat through 2029, near 0.16 (95% range 0.00–0.60). A 5-year backtest shows a typical error of ±415.8%, 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 →
0.16Projected 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 →
0.00–0.6095% 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 →
±415.8%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, Long-billed Curlew in Washington is projected to stay roughly flat through 2029, near 0.16 (95% range 0.00–0.60). A 5-year backtest shows a typical error of ±415.8%, with 100% of held-out values landing inside the 95% band.19732029
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 →
20250.180.000.62
20260.180.000.61
20270.170.000.61
20280.170.000.60
20290.160.000.60

Long-billed Curlew Survey Routes in Washington

Routes recording Long-billed Curlew 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 →
Hanford Site819941988
Richland620222006
Columbia Nwr320191992
Othello319911984
Mercer220161987
Connell220101989
Quincy220241981
Scootney Reservoir220102009
Horn Rapids220222005
Harwood219971993
Potholes220232009
Arid Land Er119891988
Brewster120021979
Moses Lake120221973
Harrington120051999
Wapato119941989
Asotin119821982
Bickleton119871982
Tonasket119971985
Wilbur120021983
Hartline120021995
Keystone120181994
Yakima120182018
Mesa120051994

Long-billed Curlew Population Trend in Other States

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