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

Grasshopper Sparrow Population Trend in Montana

All statesGrassland birds

Grasshopper Sparrow in Montana has surged: up 490% on the route-weighted index since 1970.

+490%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 →
77Routes 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 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 490% 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 17% by 2029 — from 9.7 in 2024 to a central estimate of 8.1 (95% range 4.7–11). A 5-year backtest shows a typical error of ±35.9%, with 40% of held-out values landing inside the 95% band.

-17%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 →
8.1Projected 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 →
4.7–1195% 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 →
±35.9%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 →
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 →
20257.64.211
20267.74.311
20277.84.511
20287.94.611
20298.14.711

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 →
Dinosaurs H.M.10120242018
Locate9820241981
Circle7720231969
Ester Lake6820242015
Coleman Coulee6820232017
Winnett5620232017
Saco4320242015
Redstone4220241970
Cabin Creek4020242018
Flatwillow 23720232010
Jordan South3720242016
Miles City3720242015
Hehn Draw3420242016
Lambert3320242021
Roundup2720242016
Forsyth2520231980
Albion2520241982
Webster2020241980
Oswego1920241978
Roy1720241988
Chuffey Spring1720232016
Jordan1620241970
Red Rock1520031973
Brandenberg1420191969
Lindsay1420242015

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 2026-05-22.