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

Seaside Sparrow Population Trend in Delaware

All statesGeneralists

Seaside Sparrow in Delaware has surged: up 742% on the route-weighted index since 1969.

+742%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 →
52YearsYears 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 742% 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 stay roughly flat through 2029, near 4.8 (95% range 2.4–7.3). A 5-year backtest shows a typical error of ±26.7%, with 100% of held-out values landing inside the 95% band.

+5%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 →
4.8Projected 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 →
2.4–7.395% 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 →
±26.7%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 stay roughly flat through 2029, near 4.8 (95% range 2.4–7.3). A 5-year backtest shows a typical error of ±26.7%, 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 →
20254.52.17.0
20264.62.27.0
20274.72.27.1
20284.82.37.2
20294.82.47.3

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 →
Harrington2320241967
Dover319851966
Lowes Xrds319871967
Milton219751971
Georgetown220211992
Milton 2220172017
Bethany Bch119901966
Blackbird120231994
Pepperbox120062003
Pepperbox 2120222018

Seaside Sparrow Population Trend in Other States

alabamafloridalouisianamarylandmassachusettsnew-jerseynew-yorknorth-carolinasouth-carolinatexasvirginia

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