BirdAnalyst
Species · BCR 30 · BBS 2025 Release · 1966–2024

Swamp Sparrow In New England / Mid-Atlantic Coast

All regionsNew England / Mid-Atlantic CoastGeneralists

Swamp Sparrow in New England / Mid-Atlantic Coast has held roughly steady: up 3% on the route-weighted index since 1968.

+3%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 →
58YearsYears 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.

Forecast

If the recent trend holds, Swamp Sparrow in New England / Mid-Atlantic Coast is projected to rise about 69% by 2029 — from 0.25 in 2024 to a central estimate of 0.42 (95% range 0.13–0.72). A 5-year backtest shows a typical error of ±34.3%, with 100% of held-out values landing inside the 95% band.

+69%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 →
0.42Projected 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 →
0.13–0.7295% 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 →
±34.3%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 69% by 2029 — from 0.25 in 2024 to a central estimate of 0.42 (95% range 0.13–0.72). A 5-year backtest shows a typical error of ±34.3%, with 100% 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 →
20250.430.130.72
20260.430.130.72
20270.420.130.72
20280.420.130.72
20290.420.130.72

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
Warren 2CONNECTICUT52024
N. AndoverMASSACHUSETTS52024
Woodstock 2CONNECTICUT32024
MiltonDELAWARE31980
Cape NeddickMAINE31973
WarrenMASSACHUSETTS32009
HuntingtonNEW-YORK31981
WoodstockCONNECTICUT22003
WillimanticCONNECTICUT21998
DoverDELAWARE21987
HolleyvilleDELAWARE21976
Lowes XrdsDELAWARE21969
BlackbirdDELAWARE22023
Holleyville 2DELAWARE22006
PepperboxDELAWARE22008
MelitotaMARYLAND21984
BrocktonMASSACHUSETTS22019
E PepperellMASSACHUSETTS21993
Warren 2MASSACHUSETTS22024
Ware RiverMASSACHUSETTS22022
East KingstonNEW-HAMPSHIRE22023
PomonaNEW-JERSEY22001
SpraguetownNEW-JERSEY21984

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