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

Bank Swallow Population Trend in Colorado

All statesAerial insectivores

Bank Swallow in Colorado has fallen sharply: down 54% on the route-weighted index since 1973.

-54%Since 1973TrendPercent 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 →
35Routes 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 →
42YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Bank 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 →

long arc declinecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Bank Swallow has fallen sharply in Colorado: down 53% on the route-weighted index since 1973.

Bank Swallow Population Forecast in Colorado

If the recent trend holds, Bank Swallow in Colorado is projected to stay roughly flat through 2029, near 0.22 (95% range 0.00–0.77). A 5-year backtest shows a typical error of ±1115.8%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.22Projected 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 →
0.00–0.7795% 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 →
±1115.8%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, Bank Swallow in Colorado is projected to stay roughly flat through 2029, near 0.22 (95% range 0.00–0.77). A 5-year backtest shows a typical error of ±1115.8%, 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 →
20250.240.000.79
20260.230.000.79
20270.230.000.78
20280.230.000.78
20290.220.000.77

Bank Swallow Survey Routes in Colorado

Routes recording Bank 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 →
Dolores1819741974
Fort Morgan1220211998
Prospect Val1119921992
Arsenal1020152008
Lamar1019951973
San Luis1020001997
Rifle Falls620141998
Parlin419831983
Browns Park420061994
Yellowjacket Pass420151999
Harmony319801980
Two Buttes319951982
Yampa220132008
Buford220211970
Wilson Creek219981990
Lay220181996
Antonito220001996
De Beque219951995
Paonia219981997
Piceance Basin220062004
Maybell120211994
Aspen119991986
Falfa119741974
Mica Butte119681968
Wray Gulch120051998

Bank Swallow Population Trend in Other States

alabamaalaskaarkansascaliforniaconnecticutdelawareidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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