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

Summer Tanager Population Trend in California

All statesGeneralists

Summer Tanager in California has edged down: down 22% on the route-weighted index since 1982.

-22%Since 1982TrendPercent 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 →
6Routes 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 →
18YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Summer Tanager 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 Summer Tanager in California. See the full index history below.

Summer Tanager Population Forecast in California

If the recent trend holds, Summer Tanager in California is projected to stay roughly flat through 2026, near 0.01 (95% range 0.00–0.02). A 5-year backtest shows a typical error of ±27%, 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 →
0.01Projected 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 →
0.00–0.0295% 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 →
±27%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, Summer Tanager in California is projected to stay roughly flat through 2026, near 0.01 (95% range 0.00–0.02). A 5-year backtest shows a typical error of ±27%, with 100% of held-out values landing inside the 95% band.19762026
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 →
20220.010.000.02
20230.010.000.02
20240.010.000.02
20250.010.000.02
20260.010.000.02

Summer Tanager Survey Routes in California

Routes recording Summer Tanager 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 →
Tecopa220211983
Kelso Valley120022002
Onyx120011995
Elizabeth Lk119821982
Pearblossom119971976
Brawley119881988

Summer Tanager Population Trend in Other States

alabamaarizonaarkansasdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamarylandmississippimissourinebraskanevadanew-jerseynew-mexiconorth-carolinaohiooklahomapennsylvaniasouth-carolinatennesseetexasutahvirginiawest-virginiawisconsin

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