BirdAnalyst
Species · BCR 22 · BBS 2026 Release · 1966–2025

Chestnut-sided Warbler In Eastern Tallgrass Prairie

All regionsEastern Tallgrass PrairieForest birds

Chestnut-sided Warbler in Eastern Tallgrass Prairie has edged down: down 13% on the route-weighted index since 1983.

-13%Since 1983TrendPercent 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 →
15Routes 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 →
18YearsYears 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 →

No notable trend signals for Chestnut-sided Warbler in Eastern Tallgrass Prairie. See the full index history below.

Chestnut-sided Warbler In Eastern Tallgrass Prairie Population Forecast

If the recent trend holds, Chestnut-sided Warbler in Eastern Tallgrass Prairie is projected to stay roughly flat through 2030, near 0.01 (95% range 0.00–0.01). A 5-year backtest shows a typical error of ±35.8%, with 60% of held-out values landing inside the 95% band.

n/aChange 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 →
0.01Projected 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 →
0.00–0.0195% 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 →
±35.8%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, Chestnut-sided Warbler in Eastern Tallgrass Prairie is projected to stay roughly flat through 2030, near 0.01 (95% range 0.00–0.01). A 5-year backtest shows a typical error of ±35.8%, with 60% of held-out values landing inside the 95% band.19782030
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 →
20260.010.000.01
20270.010.000.01
20280.010.000.01
20290.010.000.01
20300.010.000.01

Routes In Eastern Tallgrass Prairie

Routes recording Chestnut-sided Warbler in Eastern Tallgrass Prairie.
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 →
FairdaleILLINOIS22021
RaymondWISCONSIN22019
BarringtonILLINOIS11999
PontiacILLINOIS11992
Lake SummersetILLINOIS12009
ThorntownINDIANA11987
MuncieINDIANA11981
BerneINDIANA12025
Portage 2INDIANA12015
DinsdaleIOWA11984
WashtaIOWA11983
Rock CreekKANSAS11995
WestervilleOHIO11978
FultonOHIO11983
River FallsWISCONSIN12018

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