BirdAnalyst
Species · BCR 12 · BBS 2025 Release · 1966–2024

Savannah Sparrow In Boreal Hardwood Transition

All regionsBoreal Hardwood TransitionGrassland birds

Savannah Sparrow in Boreal Hardwood Transition has fallen sharply: down 66% on the route-weighted index since 1968.

-66%Since 1968TrendPercent 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 →
106Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
58YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable 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 →

Savannah Sparrow has fallen sharply in Boreal Hardwood Transition: down 66% on the route-weighted index since 1968.

Savannah Sparrow In Boreal Hardwood Transition Population Forecast

If the recent trend holds, Savannah Sparrow in Boreal Hardwood Transition is projected to rise about 23% by 2029 — from 4.7 in 2024 to a central estimate of 5.8 (95% range 1.4–10). A 5-year backtest shows a typical error of ±102.8%, with 40% of held-out values landing inside the 95% band.

+23%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 →
5.8Projected 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 →
1.4–1095% 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 →
±102.8%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 Boreal Hardwood Transition is projected to rise about 23% by 2029 — from 4.7 in 2024 to a central estimate of 5.8 (95% range 1.4–10). A 5-year backtest shows a typical error of ±102.8%, with 40% of held-out values landing inside the 95% band.19662029
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 →
20256.21.811
20266.11.710
20276.01.610
20285.91.510
20295.81.410

Routes In Boreal Hardwood Transition

Routes recording Savannah Sparrow in Boreal Hardwood Transition.
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 →
PickfordMICHIGAN632024
GreenbushMINNESOTA422024
Iron RiverWISCONSIN342024
Amnicon FallsWISCONSIN342024
BayfieldWISCONSIN272024
WarroadMINNESOTA252024
DebsMINNESOTA232024
Hubbard LakeMICHIGAN161996
Nett LakeMINNESOTA162024
OntonagonMICHIGAN132019
LudeMINNESOTA122023
CathroMICHIGAN92016
HerronMICHIGAN92016
BerglandMICHIGAN81990
Little ForkMINNESOTA82024
MahtowaMINNESOTA82023
McgregorMINNESOTA82024
GilmanWISCONSIN82024
BootjackMICHIGAN72023
RiggsvilleMICHIGAN72019
FloodwoodMINNESOTA72024
Lake CityMICHIGAN62022
Cedar RunMICHIGAN61999
Walloon Lake 2MICHIGAN62018
WaskishMINNESOTA62024

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