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

Northern Rough-winged Swallow Population Trend in Colorado

All statesAerial insectivores

Northern Rough-winged Swallow in Colorado has declined: down 30% on the route-weighted index since 1970.

-30%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 →
118Routes 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 Northern Rough-winged 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 Northern Rough-winged Swallow in Colorado. See the full index history below.

Northern Rough-winged Swallow Population Forecast in Colorado

If the recent trend holds, Northern Rough-winged Swallow in Colorado is projected to fall about 19% by 2030 — from 0.94 in 2025 to a central estimate of 0.77 (95% range 0.00–2.8). A 5-year backtest shows a typical error of ±48.2%, with 100% of held-out values landing inside the 95% band.

-19%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 →
0.77Projected 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 →
0.00–2.895% 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 →
±48.2%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, Northern Rough-winged Swallow in Colorado is projected to fall about 19% by 2030 — from 0.94 in 2025 to a central estimate of 0.77 (95% range 0.00–2.8). A 5-year backtest shows a typical error of ±48.2%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20260.840.002.9
20270.820.002.9
20280.800.002.9
20290.790.002.8
20300.770.002.8

Northern Rough-winged Swallow Survey Routes in Colorado

Routes recording Northern Rough-winged 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 →
Rifle Falls2220251998
Bethune2020172013
Doyle Bridge 21820251998
De Beque1220251992
Cortez1120081988
Yellowjacket Pass1020251998
Doyle Bridge919951993
Alamosa820251988
Pritchett820172008
Dolores719871968
Buford620251972
Animas620001996
Douglas Pass520241987
Moffat520031974
Pagosa Spgs519821970
Haycamp Mesa519981998
Ludlow420161998
Maybell320251972
Yampa320221969
Lost Lake320221990
Wildhorse L320142014
San Luis320151991
Summitville320001993
Browns Park320251992
Cokedale320251996

Northern Rough-winged 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 2026-08-14.