BirdAnalyst
Species · BCR 13 · BBS 2026 Release · 1966–2025

Chestnut-sided Warbler In Lower Great Lakes / St. Lawrence Plain

All regionsLower Great Lakes / St. Lawrence PlainForest birds

Chestnut-sided Warbler in Lower Great Lakes / St. Lawrence Plain has surged: up 101% on the route-weighted index since 1968.

+101%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 →
78Routes 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 surged in Lower Great Lakes / St. Lawrence Plain: up 101% on the route-weighted index since 1968.

Chestnut-sided Warbler In Lower Great Lakes / St. Lawrence Plain Population Forecast

If the recent trend holds, Chestnut-sided Warbler in Lower Great Lakes / St. Lawrence Plain is projected to fall about 18% by 2030 — from 4.1 in 2025 to a central estimate of 3.3 (95% range 2.2–4.5). A 5-year backtest shows a typical error of ±20.2%, with 60% of held-out values landing inside the 95% band.

-18%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 →
3.3Projected 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 →
2.2–4.595% 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 →
±20.2%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 Lower Great Lakes / St. Lawrence Plain is projected to fall about 18% by 2030 — from 4.1 in 2025 to a central estimate of 3.3 (95% range 2.2–4.5). A 5-year backtest shows a typical error of ±20.2%, with 60% 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 →
20263.32.24.4
20273.32.24.4
20283.32.24.4
20293.32.24.4
20303.32.24.5

Routes In Lower Great Lakes / St. Lawrence Plain

Routes recording Chestnut-sided Warbler in Lower Great Lakes / St. Lawrence Plain.
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 →
ParishvilleNEW-YORK242025
ShaftsburyVERMONT222025
Alder CreekNEW-YORK192004
N WilmurtNEW-YORK171998
BalmatNEW-YORK152008
Sugar GrovePENNSYLVANIA152025
North PownalVERMONT142025
Mt MorrisNEW-YORK132025
West BangorNEW-YORK131999
BranchportNEW-YORK112024
PhiladelphiaNEW-YORK112025
Oriskany FlsNEW-YORK102025
Cicero CtrNEW-YORK102025
PulaskiNEW-YORK102025
OgdensburgNEW-YORK92025
CastileNEW-YORK82025
EllenburgNEW-YORK82006
AusterlitzNEW-YORK72025
CayugaNEW-YORK72025
RandolphNEW-YORK62018
FowlerNEW-YORK61968
HopkintonNEW-YORK62021
BristolVERMONT62025
WillsboroNEW-YORK52024
SheridanNEW-YORK42025

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