BirdAnalyst
Species · New Jersey · BBS 2026 Release · 1966–2025

Prothonotary Warbler Population Trend in New Jersey

All statesForest birds

Prothonotary Warbler in New Jersey has surged: up 613% on the route-weighted index since 1986.

+613%Since 1986TrendPercent 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 →
14Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
29YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Prothonotary Warbler Trends in New JerseyNotable 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 Jersey: up 613% on the route-weighted index since 1986.

Prothonotary Warbler Population Forecast in New Jersey

If the recent trend holds, Prothonotary Warbler in New Jersey is projected to fall about 34% by 2030 — from 0.44 in 2025 to a central estimate of 0.29 (95% range 0.14–0.45). A 5-year backtest shows a typical error of ±41%, with 40% of held-out values landing inside the 95% band.

-34%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 →
0.29Projected 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 →
0.14–0.4595% 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 →
±41%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 Jersey is projected to fall about 34% by 2030 — from 0.44 in 2025 to a central estimate of 0.29 (95% range 0.14–0.45). A 5-year backtest shows a typical error of ±41%, with 40% of held-out values landing inside the 95% band.19792030
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 →
20260.270.110.43
20270.280.120.43
20280.280.120.44
20290.290.130.44
20300.290.140.45

Prothonotary Warbler Survey Routes in New Jersey

Routes recording Prothonotary Warbler in New Jersey.
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 →
Cape May Ch320111993
Estell Manor220252021
Pedricktown220102000
Winslow220251989
Pomona220251987
Woodbury Hgt120181986
Six Points120032003
Albion119921992
Bennett Mill119961996
Spraguetown 3120252025
Pedricktown 2120182018
Ramseysburg120052005
Friendship120251991
Villas119811979

Prothonotary Warbler Population Trend in Other States

alabamaarkansasdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamarylandmichiganminnesotamississippimissourinew-yorknorth-carolinaohiooklahomapennsylvaniasouth-carolinatennesseetexasvirginiawest-virginiawisconsin

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