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

Common Grackle Population Trend in New Jersey

All statesGeneralists

Common Grackle in New Jersey has collapsed: down 82% on the route-weighted index since 1968.

-82%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 →
44Routes 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 Common Grackle 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 declinecomputed 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 →

Common Grackle has collapsed in New Jersey: down 82% on the route-weighted index since 1968.

Common Grackle Population Forecast in New Jersey

If the recent trend holds, Common Grackle in New Jersey is projected to fall about 99% by 2030 — from 18 in 2025 to a central estimate of 0.09 (95% range 0.00–37). A 5-year backtest shows a typical error of ±29.7%, with 100% of held-out values landing inside the 95% band.

-99%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 →
0.09Projected 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 →
0.00–3795% 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 →
±29.7%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, Common Grackle in New Jersey is projected to fall about 99% by 2030 — from 18 in 2025 to a central estimate of 0.09 (95% range 0.00–37). A 5-year backtest shows a typical error of ±29.7%, with 100% 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 →
20269.50.0046
20277.20.0044
20284.80.0042
20292.50.0039
20300.090.0037

Common Grackle Survey Routes in New Jersey

Routes recording Common Grackle 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 →
Clarksville52919911969
Pedricktown26920121991
Holmansville25820091969
Masonville15019701966
Deepwater11619771969
Cape May Ch9320131992
Robbinsville9119791966
Villas8519811979
Pedricktown 28520252013
Bennett Mill8220001966
Passaic8019691969
Mt Misery7419891976
Midvale5220221967
Ramseysburg4820251995
Dover4420231977
Del Haven4219911991
Hope3919941970
Keyport3520221986
Croton3020071970
Bloomsbury2920251969
Winslow2920251989
Ancora2819771966
Croton 22420252008
Sandbrook1920251969
Greenwich1620251966

Common Grackle Population Trend in Other States

alabamaarkansascoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawest-virginiawisconsinwyoming

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