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

Mute Swan Population Trend in New Jersey

All statesWaterfowl

Mute Swan in New Jersey has collapsed: down 82% on the route-weighted index since 1972.

-82%Since 1972TrendPercent 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 →
11Routes 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 →
31YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Mute Swan 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 →

Mute Swan has collapsed in New Jersey: down 82% on the route-weighted index since 1972.

Mute Swan Population Forecast in New Jersey

If the recent trend holds, Mute Swan in New Jersey is projected to fall about 71% by 2021 — from 0.10 in 2016 to a central estimate of 0.03 (95% range 0.00–0.38). A 5-year backtest shows a typical error of ±47.9%, with 100% of held-out values landing inside the 95% band.

-71%Change by 2021TrendPercent 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 →
0.03Projected 2021 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.3895% 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 →
±47.9%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, Mute Swan in New Jersey is projected to fall about 71% by 2021 — from 0.10 in 2016 to a central estimate of 0.03 (95% range 0.00–0.38). A 5-year backtest shows a typical error of ±47.9%, with 100% of held-out values landing inside the 95% band.19672021
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 →
20170.050.000.40
20180.050.000.40
20190.040.000.39
20200.030.000.38
20210.030.000.38

Mute Swan Survey Routes in New Jersey

Routes recording Mute Swan 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 Points519981978
Midvale419991988
Toms River319681968
Woodbury Hgt219981967
Winslow219931993
Hope219921990
Ramseysburg220101995
High Point220041990
Kemah Lake120161972
Dover120161997
Cranbury120152015

Mute Swan Population Trend in Other States

californiaconnecticutdelawareillinoisindianakentuckymarylandmassachusettsmichiganminnesotanew-hampshirenew-yorkohiopennsylvaniarhode-islandvirginiawisconsin

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