BirdAnalyst
Species · Montana · BBS 2026 Release · 1966–2025

Lark Sparrow Population Trend in Montana

All statesGrassland birds

Lark Sparrow in Montana has fallen sharply: down 51% on the route-weighted index since 1970.

-51%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 →
73Routes 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 →
57YearsYears 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 MontanaNotable 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 →

Lark Sparrow has fallen sharply in Montana: down 51% on the route-weighted index since 1970.

Lark Sparrow Population Forecast in Montana

If the recent trend holds, Lark Sparrow in Montana is projected to stay roughly flat through 2030, near 2.7 (95% range 0.00–5.6). A 5-year backtest shows a typical error of ±57%, with 100% of held-out values landing inside the 95% band.

-0%Change by 2030TrendPercent 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 →
2.7Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–5.695% 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 →
±57%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 Montana is projected to stay roughly flat through 2030, near 2.7 (95% range 0.00–5.6). A 5-year backtest shows a typical error of ±57%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20262.80.005.7
20272.80.005.7
20282.80.005.7
20292.80.005.6
20302.70.005.6

Lark Sparrow Survey Routes in Montana

Routes recording Lark Sparrow in Montana.
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 →
Brandenberg5520251968
Custer3520222019
Miles City3420252015
Custer 23320252024
Forsyth2520231980
Reed Point2220251977
Muddy Creek1820152015
Glasgow1220251968
Brusett1120241982
Jordan1020241968
Ingomar920241968
Powderville920251969
Lindsay920242015
Cabin Creek920252018
Hehn Draw820252016
Chuffey Spring620252016
Circle520221970
Wolf Point520242015
Victor519961994
Sunburst419911989
Boulder420251971
Laurel420251968
St Xavier420111980
Albion420151985
Glen320251984

Lark Sparrow Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradoidahoillinoisindianaiowakansaskentuckylouisianaminnesotamississippimissourinebraskanevadanew-mexiconorth-dakotaohiooklahomaoregonsouth-dakotatennesseetexasutahwashingtonwisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.