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

Chipping Sparrow Population Trend in Iowa

All statesForest birds

Chipping Sparrow in Iowa has surged: up 671% on the route-weighted index since 1969.

+671%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 Chipping 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 →

long arc increasecomputed 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 →

Chipping Sparrow has surged in Iowa: up 671% on the route-weighted index since 1969.

Chipping Sparrow Population Forecast in Iowa

If the recent trend holds, Chipping Sparrow in Iowa is projected to rise about 61% by 2030 — from 9.9 in 2025 to a central estimate of 16 (95% range 11–21). A 5-year backtest shows a typical error of ±77.1%, with 0% of held-out values landing inside the 95% band.

+61%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 →
11–2195% 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 →
±77.1%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, Chipping Sparrow in Iowa is projected to rise about 61% by 2030 — from 9.9 in 2025 to a central estimate of 16 (95% range 11–21). A 5-year backtest shows a typical error of ±77.1%, with 0% 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 →
2026151020
2027151120
2028161120
2029161120
2030161121

Chipping Sparrow Survey Routes in Iowa

Routes recording Chipping 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 →
Red Rock3620251968
Panther3020251967
Cedar Valley2219971971
Pierson2120251968
West Liberty1920251969
College Spgs1420041989
Festina1420251968
Maquoketa1220251968
Alice1219991968
Zearing1219951974
Rock Valley1220251968
College Spgs 21220252005
Hudson1120251967
Davis Corner1120251972
Neola1020251968
Washta1020251975
Melrose920251977
Garner919931973
Wales820251989
Dinsdale820251968
Tipton820251993
Exline720251984
Bedford720251976
Brooklyn720251983
Prairieburg720251971

Chipping Sparrow Population Trend in Other States

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

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