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

Lark Sparrow Population Trend in Montana

All statesGrassland birds

Lark Sparrow in Montana has fallen sharply: down 56% on the route-weighted index since 1970.

-56%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 →
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 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 56% 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 rise about 14% by 2029 — from 2.4 in 2024 to a central estimate of 2.8 (95% range 0.00–5.7). A 5-year backtest shows a typical error of ±67.2%, with 100% of held-out values landing inside the 95% band.

+14%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 →
0.00–5.795% 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 →
±67.2%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 rise about 14% by 2029 — from 2.4 in 2024 to a central estimate of 2.8 (95% range 0.00–5.7). A 5-year backtest shows a typical error of ±67.2%, 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 →
20252.90.005.8
20262.80.005.7
20272.80.005.7
20282.80.005.7
20292.80.005.7

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 →
Custer3520222019
Brandenberg3320191968
Chuffey Spring2720242016
Forsyth2520231980
Reed Point2320241977
Laurel2320221968
Glasgow2120241968
Custer 22120242024
Muddy Creek1820152015
Miles City1220242015
Cabin Creek1220242018
Brusett1120241982
Virgelle1020111979
Jordan1020241968
Ingomar920241968
Lindsay920242015
Hehn Draw720242016
Redstone620241977
Wheat Basin620242017
Circle520221970
Wolf Point520242015
Victor519961994
Sunburst419911989
Willow Creek 2420241984
St Xavier420111980

Lark Sparrow Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradoidahoillinoisindianaiowakansaskentuckylouisianaminnesotamississippimissourinebraskanevadanew-mexiconorth-dakotaohiooklahomaoregonsouth-dakotatennesseetexasutahwashingtonwisconsinwyoming

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