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

Cliff Swallow Population Trend in Colorado

All statesAerial insectivores

Cliff Swallow in Colorado has declined: down 32% on the route-weighted index since 1970.

-32%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 →
142Routes 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 Cliff 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 Cliff Swallow in Colorado. See the full index history below.

Cliff Swallow Population Forecast in Colorado

If the recent trend holds, Cliff Swallow in Colorado is projected to rise about 35% by 2029 — from 13 in 2024 to a central estimate of 17 (95% range 3.4–31). A 5-year backtest shows a typical error of ±31.1%, with 100% of held-out values landing inside the 95% band.

+35%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 →
17Projected 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 →
3.4–3195% 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 →
±31.1%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, Cliff Swallow in Colorado is projected to rise about 35% by 2029 — from 13 in 2024 to a central estimate of 17 (95% range 3.4–31). A 5-year backtest shows a typical error of ±31.1%, 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 →
2025184.232
2026184.032
2027183.832
2028183.632
2029173.431

Cliff Swallow Survey Routes in Colorado

Routes recording Cliff 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 →
Trinchera40520221990
Cokedale35220241995
Julesburg15220211998
Kiowa13520181968
Harmony12020241973
South Fork10820021999
Ludlow10720161998
Arsenal 28420242016
Dolores7719851968
Gilpin6720241970
Powderhorn6720231994
Pagosa Spgs5919821968
Yampa5620231970
Alamosa5420241989
Doyle Bridge5219971992
Elbert5120241998
Lake City5019881988
Animas 24920182005
Piceance Basin4520121998
Tincup4120241992
Arsenal4020151995
Pritchett3920171999
Animas3820041996
Mica Butte3719871971
Falfa3520241971

Cliff Swallow Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniaconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniasouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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