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

Willet Population Trend in California

All statesShorebirds

Willet in California has declined: down 43% on the route-weighted index since 1974.

-43%Since 1974TrendPercent 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 →
52YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Willet Trends in CaliforniaNotable 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 Willet in California. See the full index history below.

Willet Population Forecast in California

If the recent trend holds, Willet in California is projected to rise about 183% by 2029 — from 0.41 in 2024 to a central estimate of 1.2 (95% range 0.39–1.9). A 5-year backtest shows a typical error of ±197.7%, with 20% of held-out values landing inside the 95% band.

+183%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 →
1.2Projected 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 →
0.39–1.995% 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 →
±197.7%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, Willet in California is projected to rise about 183% by 2029 — from 0.41 in 2024 to a central estimate of 1.2 (95% range 0.39–1.9). A 5-year backtest shows a typical error of ±197.7%, with 20% of held-out values landing inside the 95% band.19722029
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 →
20251.10.371.9
20261.10.371.9
20271.10.381.9
20281.20.391.9
20291.20.391.9

Willet Survey Routes in California

Routes recording Willet in California.
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 →
Dorris5020191972
Cedarville2220191974
Sattley1720171972
Davis Creek1520241972
Macdoel1520191973
Madeline1220241997
Ingalls819991973
Poway819731973
Clear Lk Res720181975
Goumaz520111997
Benton520241979
Eagle Lake220241975
Hackamore220092009
Crowder Flat220192002
Honey Lake220241972
Nubieber120181975
Iron Gate119911991
Likely120241974
Crowley Lake120241973
Fall River Mills120062006
Morro Bay119921992
Yreka120021974
Hat Creek119871987
Ravendale120071974

Willet Population Trend in Other States

alabamacoloradoconnecticutdelawarefloridaidaholouisianamainemarylandmassachusettsminnesotamontananebraskanevadanew-jerseynew-yorknorth-carolinanorth-dakotaoregonsouth-carolinasouth-dakotatexasutahvirginiawyoming

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