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

Lark Sparrow Population Trend in Colorado

All statesGrassland birds

Lark Sparrow in Colorado has surged: up 207% on the route-weighted index since 1970.

+207%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 →
130Routes 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 Lark 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 →

long arc increasecomputed 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 →

Lark Sparrow has surged in Colorado: up 207% on the route-weighted index since 1970.

Lark Sparrow Population Forecast in Colorado

If the recent trend holds, Lark Sparrow in Colorado is projected to stay roughly flat through 2029, near 6.1 (95% range 2.4–9.7). A 5-year backtest shows a typical error of ±10.9%, with 100% of held-out values landing inside the 95% band.

+5%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 →
6.1Projected 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 →
2.4–9.795% 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 →
±10.9%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, Lark Sparrow in Colorado is projected to stay roughly flat through 2029, near 6.1 (95% range 2.4–9.7). A 5-year backtest shows a typical error of ±10.9%, 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 →
20255.92.29.6
20265.92.39.6
20276.02.39.7
20286.02.39.7
20296.12.49.7

Lark Sparrow Survey Routes in Colorado

Routes recording Lark 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 →
Trinchera16920221990
Mica Butte7419871968
Ninaview5520241994
Walsenburg5220241994
Cone Mtn4520241988
Doyle Bridge3619971992
Baxter Pass3420241994
Pinneo3320191974
Douglas Pass3120241982
Crowley3120241989
Kirk3120231992
Boyero2920171979
Bethune2820191989
Angora2520241998
Villegreen2420241988
Arsenal 22220242016
De Beque1720241992
Mosca1620171995
Cokedale1620241995
Kiowa 21520242019
Browns Park1520241992
Sheridan Lak1420131995
Yampa1320231995
Falfa1320241971
Hudson1220241988

Lark Sparrow Population Trend in Other States

alabamaarizonaarkansascaliforniaidahoillinoisindianaiowakansaskentuckylouisianaminnesotamississippimissourimontananebraskanevadanew-mexiconorth-dakotaohiooklahomaoregonsouth-dakotatennesseetexasutahwashingtonwisconsinwyoming

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