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

Swamp Sparrow In Boreal Hardwood Transition

All regionsBoreal Hardwood TransitionWetland birds

Swamp Sparrow in Boreal Hardwood Transition has surged: up 364% on the route-weighted index since 1968.

+364%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 →
119Routes 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 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 →

Swamp Sparrow has surged in Boreal Hardwood Transition: up 364% on the route-weighted index since 1968.

Swamp Sparrow In Boreal Hardwood Transition Population Forecast

If the recent trend holds, Swamp Sparrow in Boreal Hardwood Transition is projected to rise about 38% by 2030 — from 3.8 in 2025 to a central estimate of 5.3 (95% range 4.0–6.6). A 5-year backtest shows a typical error of ±31.9%, with 40% of held-out values landing inside the 95% band.

+38%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 →
5.3Projected 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 →
4.0–6.695% 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 →
±31.9%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 →
If the recent trend holds, Swamp Sparrow in Boreal Hardwood Transition is projected to rise about 38% by 2030 — from 3.8 in 2025 to a central estimate of 5.3 (95% range 4.0–6.6). A 5-year backtest shows a typical error of ±31.9%, with 40% 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 →
20265.13.86.4
20275.13.86.4
20285.23.96.5
20295.33.96.6
20305.34.06.6

Routes In Boreal Hardwood Transition

Routes recording Swamp 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 →
WaskishMINNESOTA222025
Wigwam BayMINNESOTA212023
MahtowaMINNESOTA162023
GreenbushMINNESOTA162025
Mille LacsMINNESOTA152024
Sherry LakeMINNESOTA132022
BackusMINNESOTA122025
MuskallongeMICHIGAN112024
Crane LakeMINNESOTA112025
GlendaleMINNESOTA112025
ChisholmMINNESOTA102024
Weirgor SpringsWISCONSIN102025
Maple GroveMICHIGAN92025
Brocky LakeMICHIGAN92025
BlackduckMINNESOTA92022
CromwellMINNESOTA82025
McgregorMINNESOTA82025
TahquamenonMICHIGAN72025
Seney NwrMICHIGAN72025
JordanMINNESOTA72025
BigforkMINNESOTA72025
NebishMINNESOTA72025
GilmanWISCONSIN72025
FlambeauWISCONSIN72025
Sawbill LndgMINNESOTA62025

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