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

Northern Mockingbird Population Trend in New Jersey

All statesGeneralists

Northern Mockingbird in New Jersey has fallen sharply: down 70% on the route-weighted index since 1968.

-70%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 →
43Routes 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 Northern Mockingbird 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 →

Northern Mockingbird has fallen sharply in New Jersey: down 70% on the route-weighted index since 1968.

Northern Mockingbird Population Forecast in New Jersey

If the recent trend holds, Northern Mockingbird in New Jersey is projected to fall about 46% by 2029 — from 9.4 in 2024 to a central estimate of 5.1 (95% range 0.35–9.9). A 5-year backtest shows a typical error of ±19.5%, with 100% of held-out values landing inside the 95% band.

-46%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 →
5.1Projected 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 →
0.35–9.995% 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 →
±19.5%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, Northern Mockingbird in New Jersey is projected to fall about 46% by 2029 — from 9.4 in 2024 to a central estimate of 5.1 (95% range 0.35–9.9). A 5-year backtest shows a typical error of ±19.5%, 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 →
20256.31.511
20266.01.211
20275.70.9510
20285.40.6510
20295.10.359.9

Northern Mockingbird Survey Routes in New Jersey

Routes recording Northern Mockingbird 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 →
Pedricktown 24620242013
Pedricktown4320121991
Deepwater4219771969
Masonville3919701966
Cape May Ch3720131992
Robbinsville3119791966
Woodbury Hgt2420241967
Holmansville2320091969
Cranbury2220241987
Villas2219811979
Ancora2019771966
Bennett Mill 21720242016
Mt Misery1619891976
Clarksville1419911969
Croton 21320242008
Bennett Mill1220001966
Six Points1120241978
Roosevelt1120221986
Del Haven1119911991
Albion1020221966
Keyport1020221986
Winslow1020241989
New Bedford920241969
Croton920071970
Greenwich820241966

Northern Mockingbird Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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