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

Black-and-white Warbler Population Trend in New Jersey

All statesForest birds

Black-and-white Warbler in New Jersey has surged: up 84% on the route-weighted index since 1968.

+84%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 →
35Routes 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 →
59YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Black-and-white 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 →

Black-and-white Warbler has surged in New Jersey: up 84% on the route-weighted index since 1968.

Black-and-white Warbler Population Forecast in New Jersey

If the recent trend holds, Black-and-white Warbler in New Jersey is projected to fall about 67% by 2030 — from 2.8 in 2025 to a central estimate of 0.93 (95% range 0.00–3.2). A 5-year backtest shows a typical error of ±70.6%, with 80% of held-out values landing inside the 95% band.

-67%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 →
0.93Projected 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 →
0.00–3.295% 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 →
±70.6%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, Black-and-white Warbler in New Jersey is projected to fall about 67% by 2030 — from 2.8 in 2025 to a central estimate of 0.93 (95% range 0.00–3.2). A 5-year backtest shows a typical error of ±70.6%, with 80% of held-out values landing inside the 95% band.19662030
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 →
20260.980.003.3
20270.970.003.2
20280.960.003.2
20290.940.003.2
20300.930.003.2

Black-and-white Warbler Survey Routes in New Jersey

Routes recording Black-and-white 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 →
Spraguetown 32620252023
Pomona1620251978
Toms River1020241966
Villas519811979
Spraguetown 2320072000
Bennett Mill320001966
High Point320251977
Friendship320251977
Cape May Ch320111992
Holmansville220041969
Hope219941975
Pottersville219971979
Winslow220251989
Woodbury Hgt120141991
Greenwich120151973
Six Points119861978
Albion120051966
Ancora119721967
Sandbrook120091980
New Bedford120101993
Croton120071978
Midvale120031971
Kemah Lake120241981
Bloomsbury120101969
Dover119981977

Black-and-white Warbler Population Trend in Other States

alabamaarkansascaliforniaconnecticutdelawaregeorgiaillinoisindianakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourinebraskanew-hampshirenew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinatennesseetexasvermontvirginiawest-virginiawisconsinwyoming

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