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

Swamp Sparrow Population Trend in Delaware

All statesGeneralists

Swamp Sparrow in Delaware has held roughly steady: up 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 →
12Routes 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 →
54YearsYears 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 DelawareNotable 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 Delaware. See the full index history below.

Swamp Sparrow Population Forecast in Delaware

If the recent trend holds, Swamp Sparrow in Delaware is projected to rise about 275% by 2029 — from 0.20 in 2024 to a central estimate of 0.75 (95% range 0.00–2.1). A 5-year backtest shows a typical error of ±302.1%, with 100% of held-out values landing inside the 95% band.

+275%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 →
0.75Projected 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 →
0.00–2.195% 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 →
±302.1%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 Delaware is projected to rise about 275% by 2029 — from 0.20 in 2024 to a central estimate of 0.75 (95% range 0.00–2.1). A 5-year backtest shows a typical error of ±302.1%, 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 →
20250.760.002.1
20260.760.002.1
20270.760.002.1
20280.750.002.1
20290.750.002.1

Swamp Sparrow Survey Routes in Delaware

Routes recording Swamp Sparrow in Delaware.
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 →
Milton319801974
Dover219871967
Holleyville219761976
Lowes Xrds219691969
Blackbird220231994
Holleyville 2220062006
Pepperbox220082005
Mt Pleasant119851975
Wilmington119901967
Harrington120241967
Bethany Bch119661966
Georgetown119981998

Swamp Sparrow Population Trend in Other States

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

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