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

Herring Gull Population Trend in New Jersey

All statesWetland birds

Herring Gull in New Jersey has surged: up 66× on the route-weighted index since 1969.

66×Since 1969TrendPercent 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 →
22Routes 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 →
54YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Herring Gull 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 increasecomputed 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 →

Herring Gull has surged in New Jersey: up 66× on the route-weighted index since 1969.

Herring Gull Population Forecast in New Jersey

If the recent trend holds, Herring Gull in New Jersey is projected to fall about 75% by 2029 — from 69 in 2024 to a central estimate of 18 (95% range 0.00–36). A 5-year backtest shows a typical error of ±78.9%, with 60% of held-out values landing inside the 95% band.

-75%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 →
18Projected 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 →
0.00–3695% 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 →
±78.9%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, Herring Gull in New Jersey is projected to fall about 75% by 2029 — from 69 in 2024 to a central estimate of 18 (95% range 0.00–36). A 5-year backtest shows a typical error of ±78.9%, with 60% 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 →
2025160.0034
2026170.0035
2027170.0035
2028170.0035
2029180.0036

Herring Gull Survey Routes in New Jersey

Routes recording Herring Gull 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 →
Six Points141020241978
Del Haven3519911991
Ocean City2820241979
Bennett Mill2019941994
Spraguetown1719971993
Toms River1520241966
Cranbury1020151988
Clarksville919721972
Passaic819691969
Friendship620191980
Cape May Ch620111992
Spraguetown 2420012001
Deepwater319691969
New Bedford220022002
Midvale220001979
Dover219941994
Keyport220071990
Villas219811979
Winslow219891989
Greenwich119821968
Gillette119891989
Roosevelt119911991

Herring Gull Population Trend in Other States

alabamaalaskacaliforniacoloradoconnecticutdelawarefloridaidahoillinoisindianakansaslouisianamainemarylandmassachusettsmichiganminnesotamontananew-hampshirenew-yorknorth-carolinaohiooregonpennsylvaniarhode-islandsouth-carolinatexasvermontvirginiawashingtonwest-virginiawisconsin

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