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

Song Sparrow Population Trend in Delaware

All statesGeneralists

Song Sparrow in Delaware has edged down: down 14% on the route-weighted index since 1968.

-14%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 →
17Routes 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 →
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 Song 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 Song Sparrow in Delaware. See the full index history below.

Song Sparrow Population Forecast in Delaware

If the recent trend holds, Song Sparrow in Delaware is projected to rise about 65% by 2029 — from 9.2 in 2024 to a central estimate of 15 (95% range 8.0–22). A 5-year backtest shows a typical error of ±63.9%, with 60% of held-out values landing inside the 95% band.

+65%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 →
15Projected 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 →
8.0–2295% 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 →
±63.9%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, Song Sparrow in Delaware is projected to rise about 65% by 2029 — from 9.2 in 2024 to a central estimate of 15 (95% range 8.0–22). A 5-year backtest shows a typical error of ±63.9%, with 60% 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 →
2025157.922
2026157.922
2027157.922
2028157.922
2029158.022

Song Sparrow Survey Routes in Delaware

Routes recording Song 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 →
Bethany Bch3619901966
Milton3120161966
Harrington2320241966
Holleyville1920041966
Milton 21820172017
Dover1519871966
Blackbird1120241994
Mt Pleasant920191966
Wilmington920141966
Holleyville 2820242006
Frederica720141966
Lowes Xrds619911966
Pepperbox520161998
Frankford320121966
Millsboro320242017
Georgetown320221992
Pepperbox 2120242017

Song Sparrow Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutgeorgiaidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseeutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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