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

Cerulean Warbler In Lower Great Lakes / St. Lawrence Plain

All regionsLower Great Lakes / St. Lawrence PlainForest birds

Cerulean Warbler in Lower Great Lakes / St. Lawrence Plain has fallen sharply: down 59% on the route-weighted index since 1968.

-59%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 →
38Routes 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 →
57YearsYears 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 →

Cerulean Warbler has fallen sharply in Lower Great Lakes / St. Lawrence Plain: down 59% on the route-weighted index since 1968.

Cerulean Warbler In Lower Great Lakes / St. Lawrence Plain Population Forecast

If the recent trend holds, Cerulean Warbler in Lower Great Lakes / St. Lawrence Plain is projected to stay roughly flat through 2029, near 0.06 (95% range 0.00–0.18). A 5-year backtest shows a typical error of ±118.9%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.06Projected 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 →
0.00–0.1895% 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 →
±118.9%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, Cerulean Warbler in Lower Great Lakes / St. Lawrence Plain is projected to stay roughly flat through 2029, near 0.06 (95% range 0.00–0.18). A 5-year backtest shows a typical error of ±118.9%, 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 →
20250.070.000.18
20260.070.000.18
20270.060.000.18
20280.060.000.18
20290.060.000.18

Routes In Lower Great Lakes / St. Lawrence Plain

Routes recording Cerulean 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 →
CatskillsNEW-YORK21995
ChurchvilleNEW-YORK22006
N VictoryNEW-YORK21971
GarrettsvileOHIO21991
StrongsvilleOHIO21987
HighlandNEW-YORK11984
W ShokanNEW-YORK12001
GhentNEW-YORK12008
RomulusNEW-YORK11989
MacdougallNEW-YORK12004
Canadice LNEW-YORK12004
Cherry HillNEW-YORK11988
E YoungstownNEW-YORK12019
ByronNEW-YORK11989
N Victory 2NEW-YORK12008
Cicero CtrNEW-YORK11987
Alder CreekNEW-YORK11987
N WilmurtNEW-YORK11991
ClintonNEW-YORK11987
NaplesNEW-YORK11981
PhiladelphiaNEW-YORK12024
PittsfieldOHIO12022
WaylandOHIO12009
MiddlefieldOHIO11988
LenoxOHIO12015

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