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

Warbling Vireo In New England / Mid-Atlantic Coast

All regionsNew England / Mid-Atlantic CoastForest birds

Warbling Vireo in New England / Mid-Atlantic Coast has surged: up 263% on the route-weighted index since 1968.

+263%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 →
96Routes 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 →

Warbling Vireo has surged in New England / Mid-Atlantic Coast: up 263% on the route-weighted index since 1968.

Warbling Vireo In New England / Mid-Atlantic Coast Population Forecast

If the recent trend holds, Warbling Vireo in New England / Mid-Atlantic Coast is projected to rise about 51% by 2029 — from 1.0 in 2024 to a central estimate of 1.6 (95% range 1.1–2.0). A 5-year backtest shows a typical error of ±17.8%, with 80% of held-out values landing inside the 95% band.

+51%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 →
1.6Projected 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 →
1.1–2.095% 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 →
±17.8%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, Warbling Vireo in New England / Mid-Atlantic Coast is projected to rise about 51% by 2029 — from 1.0 in 2024 to a central estimate of 1.6 (95% range 1.1–2.0). A 5-year backtest shows a typical error of ±17.8%, with 80% 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 →
20251.51.11.9
20261.51.11.9
20271.51.11.9
20281.51.11.9
20291.61.12.0

Routes In New England / Mid-Atlantic Coast

Routes recording Warbling Vireo 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 →
E HartlandCONNECTICUT131992
Long HillCONNECTICUT112019
WillimanticCONNECTICUT92018
Warren 2MASSACHUSETTS92024
N. AndoverMASSACHUSETTS82024
BelchertownMASSACHUSETTS72024
ShermanCONNECTICUT62019
Mid HaddamCONNECTICUT62024
Woodstock 2CONNECTICUT62024
MaynardMASSACHUSETTS62022
E PepperellMASSACHUSETTS61994
PurdyNEW-YORK62022
GreenwichCONNECTICUT52018
GranbyCONNECTICUT52024
Fair HillMARYLAND51996
WarrenMASSACHUSETTS52009
ShannockRHODE-ISLAND52024
SouthingtonCONNECTICUT42024
StraffordNEW-HAMPSHIRE42024
HuntingtonNEW-YORK42023
BedfordNEW-YORK41996
Casimir Pulaski SfRHODE-ISLAND42018
UncasvilleCONNECTICUT32024
MiltonDELAWARE31972
BerlinMARYLAND32005

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