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

House Sparrow Population Trend in New Jersey

All statesGeneralists

House Sparrow in New Jersey has fallen sharply: down 66% on the route-weighted index since 1968.

-66%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 →
42Routes 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 House Sparrow 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 →

House Sparrow has fallen sharply in New Jersey: down 66% on the route-weighted index since 1968.

House Sparrow Population Forecast in New Jersey

If the recent trend holds, House Sparrow in New Jersey is projected to fall about 38% by 2029 — from 22 in 2024 to a central estimate of 14 (95% range 0.21–28). A 5-year backtest shows a typical error of ±15.6%, with 100% of held-out values landing inside the 95% band.

-38%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 →
14Projected 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 →
0.21–2895% 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 →
±15.6%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, House Sparrow in New Jersey is projected to fall about 38% by 2029 — from 22 in 2024 to a central estimate of 14 (95% range 0.21–28). A 5-year backtest shows a typical error of ±15.6%, 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 →
2025162.330
2026151.829
2027151.329
2028140.7328
2029140.2128

House Sparrow Survey Routes in New Jersey

Routes recording House Sparrow 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 →
Passaic28419691969
Cape May Ch8920131992
Clarksville8719911969
Hope7119941970
Woodbury Hgt7020241967
Villas6919811979
Del Haven6919911991
Pedricktown 26820242013
Deepwater6719771969
Holmansville6620091969
Midvale5120221967
Bloomsbury5020241970
Pedricktown4620121991
Toms River4420241966
Robbinsville3819791966
Croton 23520242008
Ocean City3420241979
Masonville3219701966
Ramseysburg2920241995
Dover2820231977
New Bedford2420241969
Winslow2420241989
Croton2220071970
Sandbrook1920241969
Bennett Mill 21720242016

House Sparrow Population Trend in Other States

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

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