BirdAnalyst
Species · BCR 30 · BBS 2025 Release · 1966–2024

Cerulean Warbler In New England / Mid-Atlantic Coast

All regionsNew England / Mid-Atlantic CoastForest birds

Cerulean Warbler in New England / Mid-Atlantic Coast has increased: up 28% on the route-weighted index since 1979.

+28%Since 1979TrendPercent 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 →
10Routes 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 →
18YearsYears 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 →

No notable trend signals for Cerulean Warbler in New England / Mid-Atlantic Coast. See the full index history below.

Forecast

If the recent trend holds, Cerulean Warbler in New England / Mid-Atlantic Coast is projected to stay roughly flat through 2028, near 0.02 (95% range 0.00–0.04). A 5-year backtest shows a typical error of ±39.7%, with 80% of held-out values landing inside the 95% band.

n/aChange by 2028TrendPercent 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 →
0.02Projected 2028 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.0495% 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 →
±39.7%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 New England / Mid-Atlantic Coast is projected to stay roughly flat through 2028, near 0.02 (95% range 0.00–0.04). A 5-year backtest shows a typical error of ±39.7%, with 80% of held-out values landing inside the 95% band.19662028
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 →
20240.020.000.04
20250.020.000.04
20260.020.000.04
20270.020.000.04
20280.020.000.04

Routes In New England / Mid-Atlantic Coast

Routes recording Cerulean Warbler in New England / Mid-Atlantic Coast.
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 →
ShermanCONNECTICUT32018
PomfretMARYLAND21966
MysticCONNECTICUT11995
UncasvilleCONNECTICUT11998
WoodstockCONNECTICUT11996
WillimanticCONNECTICUT11999
Mid HaddamCONNECTICUT12023
LargoMARYLAND11973
BerlinMARYLAND11988
Fair HillMARYLAND11995

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