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Species · California · BBS 2025 Release · 1966–2024

Gray Flycatcher Population Trend in California

All statesAerial insectivores

Gray Flycatcher in California has surged: up 13× on the route-weighted index since 1973.

13×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 →
41Routes 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 →
53YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Gray Flycatcher 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 →

long arc increasecomputed 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 →

Gray Flycatcher has surged in California: up 13× on the route-weighted index since 1973.

Gray Flycatcher Population Forecast in California

If the recent trend holds, Gray Flycatcher in California is projected to rise about 71% by 2029 — from 0.68 in 2024 to a central estimate of 1.2 (95% range 0.72–1.6). A 5-year backtest shows a typical error of ±54%, with 40% of held-out values landing inside the 95% band.

+71%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 →
0.72–1.695% 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 →
±54%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, Gray Flycatcher in California is projected to rise about 71% by 2029 — from 0.68 in 2024 to a central estimate of 1.2 (95% range 0.72–1.6). A 5-year backtest shows a typical error of ±54%, with 40% of held-out values landing inside the 95% band.19712029
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 →
20251.10.641.5
20261.10.661.5
20271.10.681.6
20281.10.701.6
20291.20.721.6

Gray Flycatcher Survey Routes in California

Routes recording Gray Flycatcher 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 →
Navarro5319931993
Crowder Flat4220192002
Ravendale2420081975
Crowley Lake2120241979
Tionesta1920212005
Clear Lk Res1520181973
Madeline1320242010
Chilcoot1020241998
Little Truckee820231997
Pine Mountain820062006
Goumaz720111999
Big Pine520241971
Last Chance520191994
Eagle Lake420241978
Benton420241975
Crestview320241997
Deep Springs320221972
Ingalls319851973
Green Valley219881977
Gazelle220172000
San Benito Mtn.220082008
Medicine Mtn.220102010
Mt Shasta219951988
Chaos Crater219941994
Bartle220211977

Gray Flycatcher Population Trend in Other States

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