BirdAnalyst
Species · BCR 13 · BBS 2025 Release · 1966–2024

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

All regionsLower Great Lakes / St. Lawrence PlainForest birds

Black-throated Green Warbler in Lower Great Lakes / St. Lawrence Plain has surged: up 80% on the route-weighted index since 1968.

+80%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 →
54Routes 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 →
58YearsYears 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 →

Black-throated Green Warbler has surged in Lower Great Lakes / St. Lawrence Plain: up 80% on the route-weighted index since 1968.

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

If the recent trend holds, Black-throated Green Warbler in Lower Great Lakes / St. Lawrence Plain is projected to rise about 41% by 2029 — from 0.17 in 2024 to a central estimate of 0.24 (95% range 0.00–0.48). A 5-year backtest shows a typical error of ±64.6%, with 100% of held-out values landing inside the 95% band.

+41%Change by 2029TrendPercent 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 →
0.24Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.4895% 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 →
±64.6%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 Green Warbler in Lower Great Lakes / St. Lawrence Plain is projected to rise about 41% by 2029 — from 0.17 in 2024 to a central estimate of 0.24 (95% range 0.00–0.48). A 5-year backtest shows a typical error of ±64.6%, with 100% of held-out values landing inside the 95% band.19662029
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 →
20250.230.000.48
20260.230.000.48
20270.230.000.48
20280.240.000.48
20290.240.000.48

Routes In Lower Great Lakes / St. Lawrence Plain

Routes recording Black-throated Green 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 →
N WilmurtNEW-YORK91998
SheridanNEW-YORK42024
WillsboroNEW-YORK32023
HarmonsburgPENNSYLVANIA31989
W ShokanNEW-YORK22019
MendonNEW-YORK22004
RandolphNEW-YORK22018
OneidaNEW-YORK21997
PhiladelphiaNEW-YORK22022
BalmatNEW-YORK22008
GarrettsvileOHIO21975
StrongsvilleOHIO21974
AkeleyPENNSYLVANIA21971
HarrisvillePENNSYLVANIA22022
BristolVERMONT21998
HighlandNEW-YORK12012
AusterlitzNEW-YORK11999
CatskillsNEW-YORK12000
GhentNEW-YORK12008
DuanesburgNEW-YORK11975
Oriskany FlsNEW-YORK12019
TrumansburgNEW-YORK12022
OrleansNEW-YORK11968
BranchportNEW-YORK12024
Canadice LNEW-YORK12022

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.