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

Grasshopper Sparrow Population Trend in Montana

All statesGrassland birds

Grasshopper Sparrow in Montana has surged: up 503% on the route-weighted index since 1970.

+503%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 →
78Routes 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 Grasshopper 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 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 →

Grasshopper Sparrow has surged in Montana: up 503% on the route-weighted index since 1970.

Grasshopper Sparrow Population Forecast in Montana

If the recent trend holds, Grasshopper Sparrow in Montana is projected to fall about 15% by 2030 — from 9.9 in 2025 to a central estimate of 8.4 (95% range 5.0–12). A 5-year backtest shows a typical error of ±36%, with 20% of held-out values landing inside the 95% band.

-15%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 →
8.4Projected 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 →
5.0–1295% 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 →
±36%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, Grasshopper Sparrow in Montana is projected to fall about 15% by 2030 — from 9.9 in 2025 to a central estimate of 8.4 (95% range 5.0–12). A 5-year backtest shows a typical error of ±36%, with 20% 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 →
20267.94.511
20278.04.611
20288.24.812
20298.34.912
20308.45.012

Grasshopper Sparrow Survey Routes in Montana

Routes recording Grasshopper 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 →
Circle7720231969
Coleman Coulee7020242017
Dinosaurs H.M.6320252018
Jordan South6120252016
Ester Lake4720252015
Winnett4720252017
Saco4220252015
Locate3820251981
Albion3820251982
Flatwillow 23720232010
Lambert3720252021
Miles City3720252015
Cabin Creek3020252018
Redstone2820251970
Powderville2820251969
Forsyth2520231980
Chuffey Spring2520252016
Roy2420251988
Wolf Creek2020252015
Hehn Draw1820252016
Ingomar1720251968
Westby1720252015
Jordan1620241970
Savage1620251970
Wheat Basin1620252017

Grasshopper Sparrow Population Trend in Other States

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

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