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

Prothonotary Warbler In New England / Mid-Atlantic Coast

All regionsNew England / Mid-Atlantic CoastForest birds

Prothonotary Warbler in New England / Mid-Atlantic Coast has surged: up 150% on the route-weighted index since 1968.

+150%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 →
65Routes 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 →

Prothonotary Warbler has surged in New England / Mid-Atlantic Coast: up 150% on the route-weighted index since 1968.

Prothonotary Warbler In New England / Mid-Atlantic Coast Population Forecast

If the recent trend holds, Prothonotary Warbler in New England / Mid-Atlantic Coast is projected to stay roughly flat through 2029, near 0.62 (95% range 0.42–0.82). A 5-year backtest shows a typical error of ±13.4%, with 80% of held-out values landing inside the 95% band.

+7%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 →
0.62Projected 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 →
0.42–0.8295% 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 →
±13.4%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, Prothonotary Warbler in New England / Mid-Atlantic Coast is projected to stay roughly flat through 2029, near 0.62 (95% range 0.42–0.82). A 5-year backtest shows a typical error of ±13.4%, 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 →
20250.600.390.80
20260.600.400.81
20270.610.410.81
20280.610.410.82
20290.620.420.82

Routes In New England / Mid-Atlantic Coast

Routes recording Prothonotary 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 →
Pepperbox 2DELAWARE82024
BerlinMARYLAND72024
CokesburyMARYLAND52024
Furnace TownMARYLAND52024
PomonaNEW-JERSEY52024
PepperboxDELAWARE42016
HongaMARYLAND32024
SinepuxentMARYLAND31977
Snow HillMARYLAND31976
Cape May ChNEW-JERSEY32011
Milton 2DELAWARE22017
Piney NeckMARYLAND22017
HarmonyMARYLAND22017
DavidsnvilleMARYLAND22023
Island CreekMARYLAND22024
IndiantownMARYLAND22014
Estell ManorNEW-JERSEY22022
PedricktownNEW-JERSEY22010
SharpsVIRGINIA22022
Colonial PkyVIRGINIA21997
BrandonVIRGINIA22024
Chincoteag WVIRGINIA22015
Mt PleasantDELAWARE11968
WilmingtonDELAWARE12005
HarringtonDELAWARE12024

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