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

Black-and-white Warbler In Lower Great Lakes / St. Lawrence Plain

All regionsLower Great Lakes / St. Lawrence PlainForest birds

Black-and-white Warbler in Lower Great Lakes / St. Lawrence Plain has surged: up 164% on the route-weighted index since 1968.

+164%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 →
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 →

Black-and-white Warbler has surged in Lower Great Lakes / St. Lawrence Plain: up 164% on the route-weighted index since 1968.

Black-and-white Warbler In Lower Great Lakes / St. Lawrence Plain Population Forecast

If the recent trend holds, Black-and-white Warbler in Lower Great Lakes / St. Lawrence Plain is projected to rise about 11% by 2030 — from 0.68 in 2025 to a central estimate of 0.75 (95% range 0.47–1.0). A 5-year backtest shows a typical error of ±18%, with 100% of held-out values landing inside the 95% band.

+11%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 →
0.75Projected 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 →
0.47–1.095% 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 →
±18%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-and-white Warbler in Lower Great Lakes / St. Lawrence Plain is projected to rise about 11% by 2030 — from 0.68 in 2025 to a central estimate of 0.75 (95% range 0.47–1.0). A 5-year backtest shows a typical error of ±18%, with 100% 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 →
20260.730.441.0
20270.730.451.0
20280.740.451.0
20290.750.461.0
20300.750.471.0

Routes In Lower Great Lakes / St. Lawrence Plain

Routes recording Black-and-white 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 →
PhiladelphiaNEW-YORK102025
EllenburgNEW-YORK62006
BalmatNEW-YORK62008
OgdensburgNEW-YORK52025
HinesburgVERMONT51994
ParishvilleNEW-YORK42025
BristolVERMONT42025
N WilmurtNEW-YORK31998
RhinebeckNEW-YORK22024
HamburgNEW-YORK21997
RandolphNEW-YORK22005
Alder CreekNEW-YORK22004
ClintonNEW-YORK21987
North EastonNEW-YORK22025
FowlerNEW-YORK21968
HopkintonNEW-YORK22021
HarmonsburgPENNSYLVANIA21989
TeeplevillePENNSYLVANIA22005
North PownalVERMONT22025
ShaftsburyVERMONT22025
HighlandNEW-YORK12011
W ShokanNEW-YORK12013
AusterlitzNEW-YORK12022
CatskillsNEW-YORK12015
GhentNEW-YORK12021

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