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

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 →
58YearsYears 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 90% by 2029 — from 20 in 2024 to a central estimate of 1.9 (95% range 0.00–39). A 5-year backtest shows a typical error of ±22%, with 100% of held-out values landing inside the 95% band.

-90%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 →
1.9Projected 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 →
0.00–3995% 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 →
±22%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 90% by 2029 — from 20 in 2024 to a central estimate of 1.9 (95% range 0.00–39). A 5-year backtest shows a typical error of ±22%, 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 →
2025110.0048
20269.10.0046
20276.70.0044
20284.30.0041
20291.90.0039

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
Pedricktown 28720242013
Villas8519811979
Bennett Mill8220001966
Passaic8019691969
Mt Misery7419891976
Greenwich5420241966
Midvale5220221967
Dover4420231977
Del Haven4219911991
Hope3919941970
Bloomsbury3720241969
Keyport3520221986
Six Points3320241978
Croton3020071970
Croton 23020242008
Ramseysburg3020241995
Ancora2819771966
Cranbury2820241987

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 2026-05-22.