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

Savannah Sparrow Population Trend in Idaho

All statesGrassland birds

Savannah Sparrow in Idaho has declined: down 27% on the route-weighted index since 1970.

-27%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 →
52Routes 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 Savannah 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 Savannah Sparrow in Idaho. See the full index history below.

Savannah Sparrow Population Forecast in Idaho

If the recent trend holds, Savannah Sparrow in Idaho is projected to rise about 202% by 2030 — from 1.3 in 2025 to a central estimate of 4.1 (95% range 1.6–6.5). A 5-year backtest shows a typical error of ±160.4%, with 20% of held-out values landing inside the 95% band.

+202%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 →
4.1Projected 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 →
1.6–6.595% 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 →
±160.4%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, Savannah Sparrow in Idaho is projected to rise about 202% by 2030 — from 1.3 in 2025 to a central estimate of 4.1 (95% range 1.6–6.5). A 5-year backtest shows a typical error of ±160.4%, 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 →
20264.01.56.4
20274.01.66.4
20284.01.66.5
20294.01.66.5
20304.11.66.5

Savannah Sparrow Survey Routes in Idaho

Routes recording Savannah 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 →
Joel1520241989
Picabo1320251988
Cascade1219841983
Cabarton1220241985
Acequia1020121979
Crane Creek1020191991
Hot Spring1019981995
Sawtooth Cty920141988
Craters820171979
Henry819831983
Sawtooth City 2820252015
Bates820231988
Cape Horn720251972
Gifford620171989
Cedar Hill620211990
Lost River520252003
Leadore520241977
Triangle420141990
Glenns Ferry419861986
Coolin420251986
Iron Springs420231988
Nezperce Nf419981992
Pasadena Val420091989
Baker320241976
Alturas319871968

Savannah Sparrow Population Trend in Other States

alaskaarizonacaliforniacoloradoconnecticutdelawareillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooregonpennsylvaniarhode-islandsouth-dakotatennesseeutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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