BirdAnalyst
Species · BCR 23 · BBS 2026 Release · 1966–2025

Chestnut-sided Warbler In Prairie Hardwood Transition

All regionsPrairie Hardwood TransitionForest birds

Chestnut-sided Warbler in Prairie Hardwood Transition has risen sharply: up 71% on the route-weighted index since 1968.

+71%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 →
110Routes 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 →

Chestnut-sided Warbler has risen sharply in Prairie Hardwood Transition: up 71% on the route-weighted index since 1968.

Chestnut-sided Warbler In Prairie Hardwood Transition Population Forecast

If the recent trend holds, Chestnut-sided Warbler in Prairie Hardwood Transition is projected to rise about 27% by 2030 — from 0.85 in 2025 to a central estimate of 1.1 (95% range 0.70–1.5). A 5-year backtest shows a typical error of ±43.1%, with 80% of held-out values landing inside the 95% band.

+27%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 →
1.1Projected 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 →
0.70–1.595% 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 →
±43.1%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, Chestnut-sided Warbler in Prairie Hardwood Transition is projected to rise about 27% by 2030 — from 0.85 in 2025 to a central estimate of 1.1 (95% range 0.70–1.5). A 5-year backtest shows a typical error of ±43.1%, with 80% 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 →
20261.00.661.4
20271.10.671.4
20281.10.681.4
20291.10.691.4
20301.10.701.5

Routes In Prairie Hardwood Transition

Routes recording Chestnut-sided Warbler in Prairie 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 →
CumberlandWISCONSIN192025
EvergreenMINNESOTA112025
Stevens PtWISCONSIN112023
Oconto FallsWISCONSIN102023
GreshamWISCONSIN72025
MerrillWISCONSIN62025
ScottvilleMICHIGAN52025
CochraneWISCONSIN52022
StetsonvilleWISCONSIN52025
Pigeon CreekWISCONSIN52025
Belding 2MICHIGAN42013
HatfieldWISCONSIN41998
Barry S.G.A.MICHIGAN32012
Caledonia 2MINNESOTA32022
DresserWISCONSIN32018
LoraineWISCONSIN32025
CadottWISCONSIN32025
MatherWISCONSIN32023
N AndoverWISCONSIN31997
RemusMICHIGAN22025
OwendaleMICHIGAN22017
Hamburg 2MICHIGAN22018
Chippewa Lk.MICHIGAN22025
New BuffaloMICHIGAN21996
Barry S.G.A. 2MICHIGAN22018

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