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

Chimney Swift Population Trend in Delaware

All statesAerial insectivores

Chimney Swift in Delaware has declined: down 38% on the route-weighted index since 1968.

-38%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 →
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 Chimney Swift 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 Chimney Swift in Delaware. See the full index history below.

Chimney Swift Population Forecast in Delaware

If the recent trend holds, Chimney Swift in Delaware is projected to stay roughly flat through 2030, near 6.4 (95% range 1.1–12). A 5-year backtest shows a typical error of ±59.8%, with 100% of held-out values landing inside the 95% band.

-9%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 →
6.4Projected 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 →
1.1–1295% 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 →
±59.8%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, Chimney Swift in Delaware is projected to stay roughly flat through 2030, near 6.4 (95% range 1.1–12). A 5-year backtest shows a typical error of ±59.8%, 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 →
20266.61.312
20276.61.312
20286.51.212
20296.51.212
20306.41.112

Chimney Swift Survey Routes in Delaware

Routes recording Chimney Swift 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 →
Dover2319871966
Lowes Xrds2019911966
Milton 22020252017
Milton1220161966
Harrington1120251966
Wilmington720141966
Bethany Bch719901966
Frederica620251966
Holleyville620041966
Mt Pleasant420191966
Holleyville 2420242006
Georgetown420181992
Pepperbox 2420252017
Frankford320121966
Pepperbox320161998
Blackbird120251994
Millsboro120192017

Chimney Swift Population Trend in Other States

alabamaarkansascoloradoconnecticutfloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawest-virginiawisconsinwyoming

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