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

Song Sparrow Population Trend in Iowa

All statesForest birds

Song Sparrow in Iowa has edged up: up 12% on the route-weighted index since 1969.

+12%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 Song Sparrow 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 →

No notable trend signals for Song Sparrow in Iowa. See the full index history below.

Song Sparrow Population Forecast in Iowa

If the recent trend holds, Song Sparrow in Iowa is projected to rise about 19% by 2030 — from 13 in 2025 to a central estimate of 16 (95% range 4.3–27). A 5-year backtest shows a typical error of ±55.2%, with 100% of held-out values landing inside the 95% band.

+19%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 →
16Projected 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 →
4.3–2795% 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 →
±55.2%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, Song Sparrow in Iowa is projected to rise about 19% by 2030 — from 13 in 2025 to a central estimate of 16 (95% range 4.3–27). A 5-year backtest shows a typical error of ±55.2%, with 100% 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 →
2026164.628
2027164.527
2028164.527
2029164.427
2030164.327

Song Sparrow Survey Routes in Iowa

Routes recording Song Sparrow 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 →
Cedar Valley5119971967
Zearing4819951967
Davis Corner4220251968
Festina3920251968
Garner2819931971
Bedford2620251972
Mt Hamill2220251967
Burchinal2220251995
College Spgs 22020252005
Desmoines1919741968
Hudson1720251967
Dinsdale1720251968
Titonka1620251968
Bryant1520251967
West Liberty1520251968
Williamsburg1420231967
Prairieburg1420251967
Melrose1320251974
Alice1319991967
Brooklyn1220251967
Kanawha1220251967
Tipton1220251993
Exline1120251974
Red Rock1020251968
Clare1020191967

Song Sparrow Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawaregeorgiaidahoillinoisindianakansaskentuckymainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseeutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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