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Species · Iowa · BBS 2026 Release · 1966–2025

American Goldfinch Population Trend in Iowa

All statesForest birds

American Goldfinch in Iowa has fallen sharply: down 58% on the route-weighted index since 1969.

-58%Since 1969TrendPercent 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 →
39Routes 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 →
58YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable American Goldfinch Trends in IowaNotable 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 →

American Goldfinch has fallen sharply in Iowa: down 58% on the route-weighted index since 1969.

American Goldfinch Population Forecast in Iowa

If the recent trend holds, American Goldfinch in Iowa is projected to rise about 25% by 2030 — from 7.0 in 2025 to a central estimate of 8.8 (95% range 3.7–14). A 5-year backtest shows a typical error of ±65.4%, with 80% of held-out values landing inside the 95% band.

+25%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 →
8.8Projected 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 →
3.7–1495% 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 →
±65.4%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, American Goldfinch in Iowa is projected to rise about 25% by 2030 — from 7.0 in 2025 to a central estimate of 8.8 (95% range 3.7–14). A 5-year backtest shows a typical error of ±65.4%, with 80% of held-out values landing inside the 95% band.19672030
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 →
20269.03.914
20278.93.914
20288.93.814
20298.83.814
20308.83.714

American Goldfinch Survey Routes in Iowa

Routes recording American Goldfinch in Iowa.
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 →
College Spgs2320041967
Zearing2019951968
Festina1720251968
Clare1520191967
Mt Hamill1420251967
West Liberty1420251968
Wales1320251967
Pierson1320251968
Exline1020251974
Davis Corner1020251968
Panther920251967
Scranton920251967
Washta920251967
Sioux City920251968
Melrose820251974
Maquoketa820251967
Gaza820251969
Bedford720251968
Brooklyn720251967
Bryant620251967
Cedar Valley619971967
Williamsburg620231967
Alice619991967
Dinsdale620251968
Garner619931971

American Goldfinch Population Trend in Other States

alabamaarkansascaliforniacoloradoconnecticutdelawaregeorgiaidahoillinoisindianakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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