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

Northern Rough-winged Swallow Population Trend in Colorado

All statesAerial insectivores

Northern Rough-winged Swallow in Colorado has declined: down 43% on the route-weighted index since 1970.

-43%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 →
117Routes 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 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 stay roughly flat through 2029, near 0.78 (95% range 0.00–2.8). A 5-year backtest shows a typical error of ±64.2%, with 100% of held-out values landing inside the 95% band.

+8%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 →
0.78Projected 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 →
0.00–2.895% 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 →
±64.2%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 stay roughly flat through 2029, near 0.78 (95% range 0.00–2.8). A 5-year backtest shows a typical error of ±64.2%, 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 →
20250.850.002.9
20260.830.002.9
20270.810.002.9
20280.790.002.9
20290.780.002.8

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 →
Walden2320181990
Bethune2020172013
Fort Morgan1820241996
Browns Park1520241992
Cortez1120081988
Rifle Falls1020211998
Rosevale920232009
Doyle Bridge919951993
Pritchett820172008
Buford720241972
Dolores719871968
Animas620001996
Douglas Pass520241987
Moffat520031974
Pagosa Spgs519821970
Haycamp Mesa519981998
Maybell420241972
Yellowjacket Pass420231998
Ludlow420161998
Yampa320221969
Falfa320241971
Wray Gulch320231988
Wilson Creek320241990
Lost Lake320221990
Wildhorse L320142014

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 2026-05-22.