BirdAnalyst
Species · New Jersey · BBS 2025 Release · 1966–2024

Worm-eating Warbler Population Trend in New Jersey

All statesForest birds

Worm-eating Warbler in New Jersey has surged: up 313% on the route-weighted index since 1979.

+313%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 →
22Routes 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 →
41YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Worm-eating 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 →

Worm-eating Warbler has surged in New Jersey: up 313% on the route-weighted index since 1979.

Worm-eating Warbler Population Forecast in New Jersey

If the recent trend holds, Worm-eating Warbler in New Jersey is projected to stay roughly flat through 2029, near 0.24 (95% range 0.00–0.49). A 5-year backtest shows a typical error of ±30.9%, with 100% of held-out values landing inside the 95% band.

+1%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 →
0.24Projected 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 →
0.00–0.4995% 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 →
±30.9%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, Worm-eating Warbler in New Jersey is projected to stay roughly flat through 2029, near 0.24 (95% range 0.00–0.49). A 5-year backtest shows a typical error of ±30.9%, with 100% of held-out values landing inside the 95% band.19742029
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 →
20250.230.000.48
20260.240.000.49
20270.240.000.49
20280.240.000.49
20290.240.000.49

Worm-eating Warbler Survey Routes in New Jersey

Routes recording Worm-eating 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 →
Greenwich320131994
Hope319941994
Bloomsbury320241987
Winslow320071991
Kemah Lake220231987
Estell Manor220222021
Spraguetown 3220232023
Woodbury Hgt120222022
Six Points120231990
Albion120102010
Bennett Mill119951992
Sandbrook119911991
New Bedford120242024
Croton119991979
Midvale120141974
High Point120161980
Dover120001987
Gillette119991997
Keyport120012001
Pomona120221982
Bennett Mill 2120222021
Ramseysburg120241995

Worm-eating Warbler Population Trend in Other States

alabamaarkansasconnecticutdelawaregeorgiaillinoisindianaiowakentuckylouisianamarylandmassachusettsmississippimissourinew-hampshirenew-yorknorth-carolinaohiooklahomapennsylvaniarhode-islandsouth-carolinatennesseetexasvirginiawest-virginiawisconsin

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