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

Kentucky Warbler Population Trend in New Jersey

All statesForest birds

Kentucky Warbler in New Jersey has edged up: up 14% on the route-weighted index since 1970.

+14%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 →
19Routes 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 →
33YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Kentucky 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 Kentucky Warbler in New Jersey. See the full index history below.

Kentucky Warbler Population Forecast in New Jersey

If the recent trend holds, Kentucky Warbler in New Jersey is projected to rise about 85% by 2019 — from 0.05 in 2014 to a central estimate of 0.10 (95% range 0.00–0.27). A 5-year backtest shows a typical error of ±85.6%, with 100% of held-out values landing inside the 95% band.

+85%Change by 2019TrendPercent 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 →
0.10Projected 2019 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.2795% 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 →
±85.6%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, Kentucky Warbler in New Jersey is projected to rise about 85% by 2019 — from 0.05 in 2014 to a central estimate of 0.10 (95% range 0.00–0.27). A 5-year backtest shows a typical error of ±85.6%, with 100% of held-out values landing inside the 95% band.19682019
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 →
20150.100.000.28
20160.100.000.28
20170.100.000.28
20180.100.000.27
20190.100.000.27

Kentucky Warbler Survey Routes in New Jersey

Routes recording Kentucky 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 →
Bennett Mill419761976
Kemah Lake219741970
Woodbury Hgt120141991
Greenwich119741968
Albion119891989
Sandbrook119971975
Croton119911989
Robbinsville119691969
Hope119921992
Bloomsbury119851985
High Point120001987
Dover120002000
Pottersville119821979
Gillette119971995
Keyport119911991
Roosevelt119941991
Friendship119911982
Pedricktown120121991
Winslow120051991

Kentucky Warbler Population Trend in Other States

alabamaarkansasdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamarylandmississippimissourinew-yorknorth-carolinaohiooklahomapennsylvaniasouth-carolinatennesseetexasvirginiawest-virginiawisconsin

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