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

Wilson's Phalarope Population Trend in California

All statesShorebirds

Wilson's Phalarope in California has held roughly steady: down 8% on the route-weighted index since 1973.

-8%Since 1973TrendPercent 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 →
22Routes 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 Wilson's Phalarope 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 Wilson's Phalarope in California. See the full index history below.

Wilson's Phalarope Population Forecast in California

If the recent trend holds, Wilson's Phalarope in California is projected to stay roughly flat through 2026, near 0.25 (95% range 0.00–0.71). A 5-year backtest shows a typical error of ±1355%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2026TrendPercent 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 →
0.25Projected 2026 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.7195% 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 →
±1355%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, Wilson's Phalarope in California is projected to stay roughly flat through 2026, near 0.25 (95% range 0.00–0.71). A 5-year backtest shows a typical error of ±1355%, with 100% of held-out values landing inside the 95% band.19702026
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 →
20220.260.000.72
20230.250.000.72
20240.250.000.71
20250.250.000.71
20260.250.000.71

Wilson's Phalarope Survey Routes in California

Routes recording Wilson's Phalarope 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 →
Dorris2020181972
Clear Lk Res1320071984
Crowder Flat1020072003
Macdoel620151984
Eagle Lake520071975
Benton420161976
Sattley320051974
Honey Lake220061972
Cedarville220181982
Ingalls219971973
Nubieber120151970
Gazelle119881988
Glenn119801980
Likely120161979
Madeline120211998
Crowley Lake120051972
Goumaz120111999
Davis Creek119901972
Zamora119881988
Yreka119991975
Ravendale120081974
Orland120111988

Wilson's Phalarope Population Trend in Other States

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