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

Mallard Population Trend in New Jersey

All statesWaterfowl

Mallard in New Jersey has fallen sharply: down 51% on the route-weighted index since 1968.

-51%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 →
36Routes 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 Mallard 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 →

Mallard has fallen sharply in New Jersey: down 51% on the route-weighted index since 1968.

Mallard Population Forecast in New Jersey

If the recent trend holds, Mallard in New Jersey is projected to stay roughly flat through 2029, near 1.1 (95% range 0.00–2.9). A 5-year backtest shows a typical error of ±170.4%, with 100% of held-out values landing inside the 95% band.

+8%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 →
1.1Projected 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 →
0.00–2.995% 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 →
±170.4%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, Mallard in New Jersey is projected to stay roughly flat through 2029, near 1.1 (95% range 0.00–2.9). A 5-year backtest shows a typical error of ±170.4%, 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 →
20251.10.003.0
20261.10.003.0
20271.10.002.9
20281.10.002.9
20291.10.002.9

Mallard Survey Routes in New Jersey

Routes recording Mallard 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 →
Mt Misery3419891976
Woodbury Hgt1220241968
Pedricktown1220121995
Holmansville920091969
Clarksville619801976
Toms River520241966
Hope519931971
Midvale520211971
Ocean City320151979
Villas319791979
Greenwich220231982
Six Points220241990
Albion220071968
Masonville219701966
Croton220031974
Robbinsville219751966
Bloomsbury220231969
Pottersville220111977
Keyport220181990
Friendship220032003
Pomona219921992
Spraguetown219971981
Pedricktown 2220192013
Winslow220071989
Spraguetown 2120032003

Mallard 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.