BirdAnalyst
Species · BCR 12 · BBS 2026 Release · 1966–2025

Vesper Sparrow In Boreal Hardwood Transition

All regionsBoreal Hardwood TransitionGrassland birds

Vesper Sparrow in Boreal Hardwood Transition has collapsed: down 77% on the route-weighted index since 1968.

-77%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 →
97Routes 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 →
59YearsYears 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 →

Vesper Sparrow has collapsed in Boreal Hardwood Transition: down 77% on the route-weighted index since 1968.

Vesper Sparrow In Boreal Hardwood Transition Population Forecast

If the recent trend holds, Vesper Sparrow in Boreal Hardwood Transition is projected to fall about 90% by 2030 — from 0.77 in 2025 to a central estimate of 0.08 (95% range 0.00–1.3). A 5-year backtest shows a typical error of ±29%, with 100% of held-out values landing inside the 95% band.

-90%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 →
0.08Projected 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 →
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 →
±29%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, Vesper Sparrow in Boreal Hardwood Transition is projected to fall about 90% by 2030 — from 0.77 in 2025 to a central estimate of 0.08 (95% range 0.00–1.3). A 5-year backtest shows a typical error of ±29%, with 100% of held-out values landing inside the 95% band.19662030
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 →
20260.310.001.5
20270.250.001.5
20280.190.001.4
20290.140.001.3
20300.080.001.3

Routes In Boreal Hardwood Transition

Routes recording Vesper 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 →
Walloon LakeMICHIGAN182004
BashawWISCONSIN112025
IronsMICHIGAN101986
RiggsvilleMICHIGAN92019
Traverse CtyMICHIGAN81992
GreenbushMINNESOTA72025
Hubbard LakeMICHIGAN51996
GooseneckMICHIGAN52010
WarroadMINNESOTA52025
Union TwpWISCONSIN52025
CreightonMICHIGAN32018
Bear LakeMICHIGAN32025
Pleasant Valley 2MICHIGAN32025
Cedar RunMICHIGAN31994
MayfieldMICHIGAN32025
Hiawatha NfMICHIGAN32025
Cluster LakesMICHIGAN32010
BemidjiMINNESOTA31980
DebsMINNESOTA32025
Little ForkMINNESOTA31973
WaskishMINNESOTA31988
MahtowaMINNESOTA32013
ChaffeyWISCONSIN31995
OntonagonMICHIGAN21971
HermanMICHIGAN21997

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