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Species · Delaware · BBS 2026 Release · 1966–2025

Seaside Sparrow Population Trend in Delaware

All statesWetland birds

Seaside Sparrow in Delaware has surged: up 660% on the route-weighted index since 1969.

+660%Since 1969TrendPercent 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 →
10Routes 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 →
53YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Seaside 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 →

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 →

Seaside Sparrow has surged in Delaware: up 660% on the route-weighted index since 1969.

Seaside Sparrow Population Forecast in Delaware

If the recent trend holds, Seaside Sparrow in Delaware is projected to rise about 26% by 2030 — from 3.8 in 2025 to a central estimate of 4.8 (95% range 2.4–7.2). A 5-year backtest shows a typical error of ±20.3%, with 100% of held-out values landing inside the 95% band.

+26%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 →
4.8Projected 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 →
2.4–7.295% 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 →
±20.3%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, Seaside Sparrow in Delaware is projected to rise about 26% by 2030 — from 3.8 in 2025 to a central estimate of 4.8 (95% range 2.4–7.2). A 5-year backtest shows a typical error of ±20.3%, 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 →
20264.52.17.0
20274.62.27.0
20284.72.27.1
20294.72.37.2
20304.82.47.2

Seaside Sparrow Survey Routes in Delaware

Routes recording Seaside 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 →
Harrington1920251967
Dover319851966
Lowes Xrds319871967
Milton219751971
Georgetown220211992
Milton 2220252017
Bethany Bch119901966
Blackbird120251994
Pepperbox120062003
Pepperbox 2120252018

Seaside Sparrow Population Trend in Other States

alabamafloridalouisianamarylandmassachusettsnew-jerseynew-yorknorth-carolinasouth-carolinatexasvirginia

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