BirdAnalyst
Species · California · BBS 2026 Release · 1966–2025

Pine Siskin Population Trend in California

All statesForest birds

Pine Siskin in California has fallen sharply: down 57% on the route-weighted index since 1970.

-57%Since 1970TrendPercent 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 →
120Routes 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 →
57YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Pine Siskin 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 declinecomputed 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 →

Pine Siskin has fallen sharply in California: down 57% on the route-weighted index since 1970.

Pine Siskin Population Forecast in California

If the recent trend holds, Pine Siskin in California is projected to fall about 36% by 2030 — from 0.91 in 2025 to a central estimate of 0.58 (95% range 0.00–1.6). A 5-year backtest shows a typical error of ±23%, with 100% of held-out values landing inside the 95% band.

-36%Change by 2030TrendPercent 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 →
0.58Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–1.695% 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 →
±23%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, Pine Siskin in California is projected to fall about 36% by 2030 — from 0.91 in 2025 to a central estimate of 0.58 (95% range 0.00–1.6). A 5-year backtest shows a typical error of ±23%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20260.650.001.7
20270.630.001.7
20280.610.001.6
20290.590.001.6
20300.580.001.6

Pine Siskin Survey Routes in California

Routes recording Pine Siskin 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 →
Colma3819721968
Point Reyes3420251971
Big Bear2519811969
Macdoel1920111974
Honeydew1620171968
Fairfax1620241972
Hay Fork1520082003
Pescadero1120251992
Crestview1120251998
Lakeshore1020051973
Offield Mtn920091975
Gazelle920011988
Burnt Ranch920162001
Rio Dell820111972
Lake Hemet819761970
Tuolumne Grove720111973
Pilot Creek719961994
Medicine Mtn.720212000
Bass Lake620112002
Onyx619941994
Butte Meadow620131974
Meadow Valley620181999
Lassen Park519871973
Martins Fy519871981
Navarro520111972

Pine Siskin Population Trend in Other States

alaskaarizonacoloradoconnecticutidahoiowamainemarylandmassachusettsmichiganminnesotamontananebraskanevadanew-hampshirenew-mexiconew-yorknorth-carolinanorth-dakotaohiooregonpennsylvaniarhode-islandsouth-dakotatennesseeutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.