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

Grasshopper Sparrow Population Trend in Idaho

All statesGrassland birds

Grasshopper Sparrow in Idaho has declined: down 47% on the route-weighted index since 1972.

-47%Since 1972TrendPercent 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 →
31Routes 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 →
54YearsYears 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 IdahoNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Grasshopper Sparrow in Idaho. See the full index history below.

Grasshopper Sparrow Population Forecast in Idaho

If the recent trend holds, Grasshopper Sparrow in Idaho is projected to fall about 63% by 2029 — from 1.0 in 2024 to a central estimate of 0.37 (95% range 0.00–1.3). A 5-year backtest shows a typical error of ±72.2%, with 100% of held-out values landing inside the 95% band.

-63%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 →
0.37Projected 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 →
0.00–1.395% 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 →
±72.2%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, Grasshopper Sparrow in Idaho is projected to fall about 63% by 2029 — from 1.0 in 2024 to a central estimate of 0.37 (95% range 0.00–1.3). A 5-year backtest shows a typical error of ±72.2%, 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 →
20250.400.001.3
20260.390.001.3
20270.390.001.3
20280.380.001.3
20290.370.001.3

Grasshopper Sparrow Survey Routes in Idaho

Routes recording Grasshopper Sparrow in Idaho.
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 →
Lost River1020242001
Springfield919861974
Crane Creek920191988
Blacks Creek819691968
Twin Buttes620241998
Centerville519721972
Blackft Res320082004
Tractor Flat320241997
Squirrel320241991
Picabo320212013
Circular Bu220241999
Baker220022002
Craters220041984
Carey220072001
Cedar Hill220221992
Daniels Res220081988
Pasadena Val220091987
Gifford120162005
Kyle Canyon120241999
Leadore120022002
Dubois120231973
Ririe120112011
Magic Mtn120121990
Acequia120061988
Henry119751973

Grasshopper Sparrow Population Trend in Other States

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

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