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

Barn Swallow Population Trend in Colorado

All statesAerial insectivores

Barn Swallow in Colorado has declined: down 47% on the route-weighted index since 1970.

-47%Since 1970TrendPercent 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 →
140Routes 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 →
56YearsYears 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 ColoradoNotable 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 Colorado. See the full index history below.

Barn Swallow Population Forecast in Colorado

If the recent trend holds, Barn Swallow in Colorado is projected to rise about 66% by 2029 — from 2.3 in 2024 to a central estimate of 3.9 (95% range 0.00–11). A 5-year backtest shows a typical error of ±95.3%, with 100% of held-out values landing inside the 95% band.

+66%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 →
3.9Projected 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 →
0.00–1195% 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 →
±95.3%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 Colorado is projected to rise about 66% by 2029 — from 2.3 in 2024 to a central estimate of 3.9 (95% range 0.00–11). A 5-year backtest shows a typical error of ±95.3%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20254.50.0012
20264.30.0012
20274.20.0012
20284.00.0011
20293.90.0011

Barn Swallow Survey Routes in Colorado

Routes recording Barn Swallow in Colorado.
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 →
Dolores15919871968
Browns Park3620071995
Julesburg3020211998
Kirk2620231992
Fort Morgan2620241996
Two Buttes2420151973
Gordon Creek2220221988
Prospect Val2220001992
Doyle Bridge2219971992
Alamosa2020241988
Mica Butte1819871968
Bennett1620181995
Douglas Pass1520241985
Hudson1520241988
Sheridan Lak1420161995
Neegrande1220241992
Ludlow1220161998
Animas 21220182006
Cortez 21120172009
Buford1020241970
Wray Gulch920231988
Trinchera920221990
Stoneham920211992
Harmony820241973
Moffat820241970

Barn Swallow Population Trend in Other States

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

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.