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

Song Sparrow Population Trend in Colorado

All statesGeneralists

Song Sparrow in Colorado has edged down: down 13% on the route-weighted index since 1970.

-13%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 →
115Routes 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 Song Sparrow 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 Song Sparrow in Colorado. See the full index history below.

Song Sparrow Population Forecast in Colorado

If the recent trend holds, Song Sparrow in Colorado is projected to stay roughly flat through 2029, near 2.8 (95% range 0.78–4.9). A 5-year backtest shows a typical error of ±9.9%, with 100% of held-out values landing inside the 95% band.

-6%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 →
2.8Projected 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 →
0.78–4.995% 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 →
±9.9%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, Song Sparrow in Colorado is projected to stay roughly flat through 2029, near 2.8 (95% range 0.78–4.9). A 5-year backtest shows a typical error of ±9.9%, 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 →
20252.90.814.9
20262.80.814.9
20272.80.804.9
20282.80.794.9
20292.80.784.9

Song Sparrow Survey Routes in Colorado

Routes recording Song Sparrow 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 →
Yampa4320231969
Aspen3420241979
Yellowjacket Pass2320241998
Stillwater Pass 22120242010
Heeney1820192017
Fox Creek1720241993
Moon Pass1720241998
Red Cliff1420241989
Rifle Falls1420211998
Buford1320241972
Castleton1220241988
Parlin1020231968
Wilson Creek920241990
Rio Grnds Rs920241991
Stillwater Pass920091998
Dolores Riv820241988
Alamosa820241988
Deadman Rd.820241992
Thomasville820181992
Ragged Mtn.820191994
Powderhorn820231995
Blackhead Pk720211991
Radium720131998
Black Sulphur Cr720242015
Wray Gulch620231988

Song Sparrow Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniaconnecticutdelawaregeorgiaidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseeutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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