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

Great-tailed Grackle Population Trend in California

All statesGeneralists

Great-tailed Grackle in California has surged: up 46× on the route-weighted index since 1977.

46×Since 1977TrendPercent 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 →
65Routes 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 Great-tailed Grackle 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 →

Great-tailed Grackle has surged in California: up 46× on the route-weighted index since 1977.

Great-tailed Grackle Population Forecast in California

If the recent trend holds, Great-tailed Grackle in California is projected to rise about 108% by 2029 — from 1.6 in 2024 to a central estimate of 3.4 (95% range 0.11–6.7). A 5-year backtest shows a typical error of ±179%, with 100% of held-out values landing inside the 95% band.

+108%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 →
3.4Projected 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 →
0.11–6.795% 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 →
±179%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, Great-tailed Grackle in California is projected to rise about 108% by 2029 — from 1.6 in 2024 to a central estimate of 3.4 (95% range 0.11–6.7). A 5-year backtest shows a typical error of ±179%, 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 →
20253.20.006.5
20263.20.006.5
20273.30.016.6
20283.30.066.6
20293.40.116.7

Great-tailed Grackle Survey Routes in California

Routes recording Great-tailed Grackle 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 →
Imperial Dam13720101973
Palo Verde9320241973
Alamo River9320181979
Brawley9120121983
Blythe5420032003
Parker Dam4520072003
Coachella Cn3620132000
Niland2620241979
Buena Vista820192018
Moreno720242012
Orland720222011
Ora Loma620242024
Orange Cove520122000
Athlone520072003
Creston420212021
Calif City420151995
Glamis420182018
Harbor Lake 2420242016
Pearblossom420242004
Silver City420132013
Elizabeth Lk320162012
Pennington320242009
Atwater320072007
Zamora320222019
Havasu Lake320032003

Great-tailed Grackle Population Trend in Other States

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