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

Chestnut-sided Warbler Population Trend in New Jersey

All statesForest birds

Chestnut-sided Warbler in New Jersey has increased: up 47% on the route-weighted index since 1970.

+47%Since 1970TrendPercent 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 →
20Routes 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 →
55YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Chestnut-sided 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 →

No notable trend signals for Chestnut-sided Warbler in New Jersey. See the full index history below.

Chestnut-sided Warbler Population Forecast in New Jersey

If the recent trend holds, Chestnut-sided Warbler in New Jersey is projected to rise about 102% by 2029 — from 0.19 in 2024 to a central estimate of 0.38 (95% range 0.00–0.77). A 5-year backtest shows a typical error of ±147.7%, with 100% of held-out values landing inside the 95% band.

+102%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 →
0.38Projected 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 →
0.00–0.7795% 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 →
±147.7%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, Chestnut-sided Warbler in New Jersey is projected to rise about 102% by 2029 — from 0.19 in 2024 to a central estimate of 0.38 (95% range 0.00–0.77). A 5-year backtest shows a typical error of ±147.7%, with 100% 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 →
20250.370.000.76
20260.380.000.76
20270.380.000.76
20280.380.000.76
20290.380.000.77

Chestnut-sided Warbler Survey Routes in New Jersey

Routes recording Chestnut-sided 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 →
Roosevelt520071990
High Point320241977
Toms River119661966
Sandbrook120051969
New Bedford119711971
Croton120071980
Robbinsville119771977
Hope119931978
Midvale119881970
Kemah Lake120151975
Bloomsbury119911991
Dover120221978
Pottersville120181980
Gillette120241997
Keyport120022002
Cranbury119871987
Friendship119821982
Pedricktown119981997
Croton 2120232008
Ramseysburg120162010

Chestnut-sided Warbler Population Trend in Other States

alabamaarkansascoloradoconnecticutgeorgiaillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotanevadanew-hampshirenew-yorknorth-carolinanorth-dakotaohiopennsylvaniarhode-islandtennesseevermontvirginiawest-virginiawisconsinwyoming

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