BirdAnalyst
Species · BCR 30 · BBS 2026 Release · 1966–2025

Swamp Sparrow In New England / Mid-Atlantic Coast

All regionsNew England / Mid-Atlantic CoastWetland birds

Swamp Sparrow in New England / Mid-Atlantic Coast has held roughly steady: down 7% on the route-weighted index since 1968.

-7%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 →
76Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
59YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Swamp Sparrow in New England / Mid-Atlantic Coast. See the full index history below.

Swamp Sparrow In New England / Mid-Atlantic Coast Population Forecast

If the recent trend holds, Swamp Sparrow in New England / Mid-Atlantic Coast is projected to rise about 38% by 2030 — from 0.30 in 2025 to a central estimate of 0.41 (95% range 0.12–0.71). A 5-year backtest shows a typical error of ±36.5%, with 100% of held-out values landing inside the 95% band.

+38%Change by 2030TrendPercent 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 →
0.41Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.12–0.7195% 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 →
±36.5%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, Swamp Sparrow in New England / Mid-Atlantic Coast is projected to rise about 38% by 2030 — from 0.30 in 2025 to a central estimate of 0.41 (95% range 0.12–0.71). A 5-year backtest shows a typical error of ±36.5%, with 100% of held-out values landing inside the 95% band.19662030
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 →
20260.420.120.71
20270.410.120.71
20280.410.120.71
20290.410.120.71
20300.410.120.71

Routes In New England / Mid-Atlantic Coast

Routes recording Swamp Sparrow in New England / Mid-Atlantic Coast.
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 →
WarrenCONNECTICUT342011
BuckinghamCONNECTICUT52004
MaynardMASSACHUSETTS52025
Warren 2CONNECTICUT42025
N. AndoverMASSACHUSETTS42025
Woodstock 2CONNECTICUT32024
MiltonDELAWARE31980
Cape NeddickMAINE31973
WarrenMASSACHUSETTS32009
HuntingtonNEW-YORK31981
WoodstockCONNECTICUT22003
WillimanticCONNECTICUT21998
No WoodburyCONNECTICUT22025
DoverDELAWARE21987
HolleyvilleDELAWARE21976
Lowes XrdsDELAWARE21969
BlackbirdDELAWARE22023
Holleyville 2DELAWARE22006
PepperboxDELAWARE22008
MelitotaMARYLAND21984
BrocktonMASSACHUSETTS22019
E PepperellMASSACHUSETTS21993
Warren 2MASSACHUSETTS22025
Ware RiverMASSACHUSETTS22022
PomonaNEW-JERSEY22001

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.