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

Black-throated Blue Warbler In Lower Great Lakes / St. Lawrence Plain

All regionsLower Great Lakes / St. Lawrence PlainForest birds

Black-throated Blue Warbler in Lower Great Lakes / St. Lawrence Plain has fallen sharply: down 57% on the route-weighted index since 1969.

-57%Since 1969TrendPercent 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 →
31Routes 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 →
56YearsYears 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 →

Black-throated Blue Warbler has fallen sharply in Lower Great Lakes / St. Lawrence Plain: down 57% on the route-weighted index since 1969.

Black-throated Blue Warbler In Lower Great Lakes / St. Lawrence Plain Population Forecast

If the recent trend holds, Black-throated Blue Warbler in Lower Great Lakes / St. Lawrence Plain is projected to fall about 46% by 2030 — from 0.11 in 2025 to a central estimate of 0.06 (95% range 0.00–0.18). A 5-year backtest shows a typical error of ±81.1%, with 100% of held-out values landing inside the 95% band.

-46%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 →
0.06Projected 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 →
0.00–0.1895% 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 →
±81.1%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, Black-throated Blue Warbler in Lower Great Lakes / St. Lawrence Plain is projected to fall about 46% by 2030 — from 0.11 in 2025 to a central estimate of 0.06 (95% range 0.00–0.18). A 5-year backtest shows a typical error of ±81.1%, with 100% of held-out values landing inside the 95% band.19672030
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 →
20260.070.000.19
20270.060.000.19
20280.060.000.19
20290.060.000.18
20300.060.000.18

Routes In Lower Great Lakes / St. Lawrence Plain

Routes recording Black-throated Blue 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 →
North PownalVERMONT32025
ColchesterVERMONT31991
OneidaNEW-YORK21992
SalemNEW-YORK22001
BalmatNEW-YORK22008
ShaftsburyVERMONT22023
HighlandNEW-YORK12008
W ShokanNEW-YORK12018
AusterlitzNEW-YORK11998
CatskillsNEW-YORK11976
Oriskany FlsNEW-YORK12010
RomulusNEW-YORK11968
TrumansburgNEW-YORK11976
BranchportNEW-YORK12011
Canadice LNEW-YORK12019
MendonNEW-YORK11991
Cherry HillNEW-YORK12009
ByronNEW-YORK11977
PulaskiNEW-YORK11979
Alder CreekNEW-YORK11984
N WilmurtNEW-YORK11998
North EastonNEW-YORK12007
WaddingtonNEW-YORK11998
OgdensburgNEW-YORK11996
ParishvilleNEW-YORK12025

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