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

Swamp Sparrow Population Trend in New Jersey

All statesGeneralists

Swamp Sparrow in New Jersey has collapsed: down 80% on the route-weighted index since 1968.

-80%Since 1968
16Routes In State
55Years

Notable Swamp Sparrow Trends in New Jersey

long arc declinecomputed index

Swamp Sparrow has collapsed in New Jersey: down 80% on the route-weighted index since 1968.

Swamp Sparrow Population Forecast in New Jersey

If the recent trend holds, Swamp Sparrow in New Jersey is projected to rise about 127% by 2029 — from 0.10 in 2024 to a central estimate of 0.22 (95% range 0.00–0.54). A 5-year backtest shows a typical error of ±137.2%, with 100% of held-out values landing inside the 95% band.

+127%Change by 2029
0.22Projected 2029 index
0.00–0.5495% range
±137.2%Backtest error
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 index95% low95% high
20250.230.000.55
20260.230.000.55
20270.220.000.55
20280.220.000.54
20290.220.000.54

Swamp Sparrow Survey Routes in New Jersey

Routes recording Swamp Sparrow in New Jersey.
Spraguetown219841977
Hope219901972
High Point220221977
Pomona220011978
Greenwich119881967
Six Points119901983
Deepwater119771969
Masonville119701966
New Bedford119781978
Midvale120061972
Kemah Lake120241986
Ramseysburg120121995
Dover120231977
Gillette120241988
Roosevelt119951986
Friendship120191977

Swamp Sparrow Population Trend in Other States

connecticutdelawareillinoisindianaiowamainemarylandmassachusettsmichiganminnesotanebraskanew-hampshirenew-yorknorth-dakotaohiopennsylvaniarhode-islandsouth-dakotavermontvirginiawest-virginiawisconsin

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