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

Barn Swallow Population Trend in Iowa

All statesAerial insectivores

Barn Swallow in Iowa has edged up: up 16% on the route-weighted index since 1969.

+16%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 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 stay roughly flat through 2029, near 26 (95% range 13–39). A 5-year backtest shows a typical error of ±30.5%, with 100% of held-out values landing inside the 95% band.

+5%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 →
26Projected 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 →
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 →
±30.5%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 stay roughly flat through 2029, near 26 (95% range 13–39). A 5-year backtest shows a typical error of ±30.5%, 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 →
2025261340
2026261340
2027261339
2028261339
2029261339

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 →
Neola5220161968
Zearing5219951967
Cedar Valley5119971967
Scranton5120241967
Williamsburg4320231967
College Spgs4020041967
Mccallsburg4020241996
Bryant3720241967
West Liberty3720241968
Kanawha3420241967
Pierson3420191968
Davis Corner3320241968
Gaza3320231969
Lafayette3320242003
Red Rock3120241968
Prairieburg2820241967
Clare2720191967
Mt Hamill2520241967
Rock Valley2420241968
Alice2219991967
Maquoketa2120241967
College Spgs 22120232005
Tipton2120241993
Exline2020241974
Bedford2020181968

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 2026-05-22.