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

Bank Swallow Population Trend in Delaware

All statesAerial insectivores

Bank Swallow in Delaware has fallen sharply: down 58% on the route-weighted index since 1969.

-58%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 →
8Routes 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 →
40YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Bank Swallow 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 declinecomputed 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 →

Bank Swallow has fallen sharply in Delaware: down 57% on the route-weighted index since 1969.

Bank Swallow Population Forecast in Delaware

If the recent trend holds, Bank Swallow in Delaware is projected to rise about 189% by 2030 — from 0.50 in 2025 to a central estimate of 1.4 (95% range 0.00–5.1). A 5-year backtest shows a typical error of ±316.6%, with 100% of held-out values landing inside the 95% band.

+189%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 →
1.4Projected 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 →
0.00–5.195% 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 →
±316.6%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, Bank Swallow in Delaware is projected to rise about 189% by 2030 — from 0.50 in 2025 to a central estimate of 1.4 (95% range 0.00–5.1). A 5-year backtest shows a typical error of ±316.6%, 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 →
20261.50.005.2
20271.50.005.2
20281.50.005.2
20291.50.005.1
20301.40.005.1

Bank Swallow Survey Routes in Delaware

Routes recording Bank Swallow 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 →
Mt Pleasant1220151984
Holleyville620031995
Milton419691969
Harrington320251968
Blackbird220032003
Wilmington119681966
Frederica119751975
Lowes Xrds119751972

Bank Swallow Population Trend in Other States

alabamaalaskaarkansascaliforniacoloradoconnecticutidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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