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

American Goldfinch Population Trend in Iowa

All statesGeneralists

American Goldfinch in Iowa has fallen sharply: down 60% on the route-weighted index since 1969.

-60%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 →
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 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 60% 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 63% by 2029 — from 5.5 in 2024 to a central estimate of 9.0 (95% range 3.9–14). A 5-year backtest shows a typical error of ±65.2%, with 60% of held-out values landing inside the 95% band.

+63%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 →
9.0Projected 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 →
3.9–1495% 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 →
±65.2%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 63% by 2029 — from 5.5 in 2024 to a central estimate of 9.0 (95% range 3.9–14). A 5-year backtest shows a typical error of ±65.2%, with 60% of held-out values landing inside the 95% band.19672029
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 →
20259.24.114
20269.14.114
20279.14.014
20289.04.014
20299.03.914

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 Spgs 22520232005
Washta2420141967
College Spgs2320041967
Zearing2019951968
Hudson1720221967
Clare1520191967
Red Rock1320241968
Festina1320241968
Bryant1220241967
Melrose1120241974
Davis Corner1120241968
Brooklyn1020221967
Wales1020181967
Mt Hamill820241967
Panther820241967
Burchinal720241995
Cedar Valley619971967
Williamsburg620231967
Alice619991967
Garner619931971
Bedford520181968
West Liberty520241968
Maquoketa520241967
Prairieburg520241967
Mccallsburg520241996

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 2026-05-22.