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

Clapper Rail Population Trend in Delaware

All statesWetland birds

Clapper Rail in Delaware has surged: up 141% on the route-weighted index since 1968.

+141%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 →
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 →
50YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Clapper Rail 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 →

Clapper Rail has surged in Delaware: up 141% on the route-weighted index since 1968.

Clapper Rail Population Forecast in Delaware

If the recent trend holds, Clapper Rail in Delaware is projected to stay roughly flat through 2030, near 0.81 (95% range 0.00–1.8). A 5-year backtest shows a typical error of ±101.7%, with 80% of held-out values landing inside the 95% band.

-3%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 →
0.81Projected 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 →
0.00–1.895% 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 →
±101.7%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, Clapper Rail in Delaware is projected to stay roughly flat through 2030, near 0.81 (95% range 0.00–1.8). A 5-year backtest shows a typical error of ±101.7%, with 80% 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 →
20260.780.001.8
20270.790.001.8
20280.800.001.8
20290.800.001.8
20300.810.001.8

Clapper Rail Survey Routes in Delaware

Routes recording Clapper Rail 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 →
Milton419751971
Bethany Bch319901967
Harrington220251966
Lowes Xrds219761968
Pepperbox 2220252018
Dover119791969
Blackbird120251995
Georgetown120111992

Clapper Rail Population Trend in Other States

alabamaconnecticutfloridageorgialouisianamarylandnew-jerseynew-yorknorth-carolinasouth-carolinatexasvirginia

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