BirdAnalyst
Species · Massachusetts · BBS 2025 Release · 1966–2024

Swamp Sparrow Population Trend in Massachusetts

All statesGeneralists

Swamp Sparrow in Massachusetts has surged: up 87% on the route-weighted index since 1968.

+87%Since 1968
24Routes In State
58Years

Notable Swamp Sparrow Trends in Massachusetts

long arc increasecomputed index

Swamp Sparrow has surged in Massachusetts: up 87% on the route-weighted index since 1968.

Swamp Sparrow Population Forecast in Massachusetts

If the recent trend holds, Swamp Sparrow in Massachusetts is projected to fall about 14% by 2029 — from 1.1 in 2024 to a central estimate of 0.98 (95% range 0.43–1.5). A 5-year backtest shows a typical error of ±23.4%, with 100% of held-out values landing inside the 95% band.

-14%Change by 2029
0.98Projected 2029 index
0.43–1.595% range
±23.4%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
20250.970.421.5
20260.970.431.5
20270.970.431.5
20280.970.431.5
20290.980.431.5

Swamp Sparrow Survey Routes in Massachusetts

Routes recording Swamp Sparrow in Massachusetts.
N. Andover520241995
Chesterfield420241967
Pittsfield420161974
Warren320091968
Sheffield320131969
Monterey320242019
Cummington 2320192015
Ware River220221993
Brockton220191971
E Pepperell219931966
N Orange220241969
Warren 2220242010
Marion120232023
Prattville119981998
Newburyport120221967
Maynard120221967
Littleton120241968
N Oxford120071971
Princeton119741974
Belchertown120211967
S Barre120221968
Cummington120031981
Cheshire119941970
Holden120091977

Swamp Sparrow Population Trend in Other States

connecticutdelawareillinoisindianaiowamainemarylandmichiganminnesotanebraskanew-hampshirenew-jerseynew-yorknorth-dakotaohiopennsylvaniarhode-islandsouth-dakotavermontvirginiawest-virginiawisconsin

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