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

Song Sparrow Population Trend in Iowa

All statesGeneralists

Song Sparrow in Iowa has held roughly steady: up 5% on the route-weighted index since 1969.

+5%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 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 28% by 2029 — from 13 in 2024 to a central estimate of 16 (95% range 4.5–28). A 5-year backtest shows a typical error of ±48.1%, with 100% of held-out values landing inside the 95% band.

+28%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 →
16Projected 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 →
4.5–2895% 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 →
±48.1%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 28% by 2029 — from 13 in 2024 to a central estimate of 16 (95% range 4.5–28). A 5-year backtest shows a typical error of ±48.1%, with 100% 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 →
2025164.828
2026164.728
2027164.728
2028164.628
2029164.528

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 →
Davis Corner5920241968
Cedar Valley5119971967
Zearing4819951967
Festina4620241968
Garner2819931971
Brooklyn2320221967
Desmoines1919741968
Burchinal1920241995
West Liberty1720241968
Bedford1620181972
Bryant1520241967
Hudson1520221967
Mt Hamill1420241967
Williamsburg1420231967
Maquoketa1420241967
Alice1319991967
Melrose1120241974
Prairieburg1120241967
Dinsdale1120241968
Lafayette1120242003
Clare1020191967
Wales920181967
Tipton820241993
Exline720241974
Red Rock720241968

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 2026-05-22.