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

Barn Swallow Population Trend in Iowa

All statesAerial insectivores

Barn Swallow in Iowa has increased: up 32% on the route-weighted index since 1969.

+32%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 Barn Swallow 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 Barn Swallow in Iowa. See the full index history below.

Barn Swallow Population Forecast in Iowa

If the recent trend holds, Barn Swallow in Iowa is projected to fall about 10% by 2030 — from 29 in 2025 to a central estimate of 26 (95% range 13–39). A 5-year backtest shows a typical error of ±24.9%, with 100% of held-out values landing inside the 95% band.

-10%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 →
26Projected 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 →
13–3995% 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 →
±24.9%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, Barn Swallow in Iowa is projected to fall about 10% by 2030 — from 29 in 2025 to a central estimate of 26 (95% range 13–39). A 5-year backtest shows a typical error of ±24.9%, 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 →
2026261340
2027261340
2028261339
2029261339
2030261339

Barn Swallow Survey Routes in Iowa

Routes recording Barn Swallow 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 →
Hudson7020251967
Bryant6520251967
Pierson6420251968
Zearing5219951967
Cedar Valley5119971967
Scranton5020251967
Red Rock4920251968
College Spgs 24920252005
Williamsburg4320231967
Washta4320251967
College Spgs4020041967
Mccallsburg3720251996
Sioux City3520251968
Neola3320251968
Gaza3320251969
Davis Corner3120251968
Tipton3120251993
Kanawha2920251967
Mt Hamill2820251967
Maquoketa2720251967
Clare2720191967
Festina2420251968
Titonka2420251968
Rock Valley2420251968
Burchinal2420251995

Barn Swallow 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.