BirdAnalyst
Species · Vermont · BBS 2026 Release · 1966–2025

Swamp Sparrow Population Trend in Vermont

All statesWetland birds

Swamp Sparrow in Vermont has risen sharply: up 56% on the route-weighted index since 1968.

+56%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 →
24Routes 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 →
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 Swamp Sparrow Trends in VermontNotable 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 increasecomputed 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 →

Swamp Sparrow has risen sharply in Vermont: up 56% on the route-weighted index since 1968.

Swamp Sparrow Population Forecast in Vermont

If the recent trend holds, Swamp Sparrow in Vermont is projected to stay roughly flat through 2030, near 2.1 (95% range 0.81–3.5). A 5-year backtest shows a typical error of ±48.2%, with 100% of held-out values landing inside the 95% band.

-1%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 →
2.1Projected 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 →
0.81–3.595% 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 →
±48.2%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 Vermont is projected to stay roughly flat through 2030, near 2.1 (95% range 0.81–3.5). A 5-year backtest shows a typical error of ±48.2%, 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 →
20262.10.783.4
20272.10.793.5
20282.10.793.5
20292.10.803.5
20302.10.813.5

Swamp Sparrow Survey Routes in Vermont

Routes recording Swamp Sparrow in Vermont.
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 →
W Rutland1420251966
Hinesburg1419941977
Hardwick920241966
Stowe620241989
Bristol620251995
North Pownal420251967
Landgrove420251970
Middlesex420251968
S Wallingfrd320221966
Marlboro219671967
East Calais220251966
Greensboro220251967
Waterville219801979
Grand Isle220231967
Stratton120231966
S Reading120221969
Post Mills120251967
Shaftsbury120241973
St Johnsbury120251973
East Haven120251966
Northfld Fls120181980
Fletcher120111993
Colchester120221999
Newbury 2120152009

Swamp Sparrow Population Trend in Other States

connecticutdelawareillinoisindianaiowamainemarylandmassachusettsmichiganminnesotanebraskanew-hampshirenew-jerseynew-yorknorth-dakotaohiopennsylvaniarhode-islandsouth-dakotavirginiawest-virginiawisconsin

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