BirdAnalyst
Species · New Jersey · BBS 2026 Release · 1966–2025

Clapper Rail Population Trend in New Jersey

All statesWetland birds

Clapper Rail in New Jersey has risen sharply: up 58% on the route-weighted index since 1981.

+58%Since 1981TrendPercent 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 →
3Routes 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 →
36YearsYears 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 New JerseyNotable 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 risen sharply in New Jersey: up 58% on the route-weighted index since 1981.

Clapper Rail Population Forecast in New Jersey

If the recent trend holds, Clapper Rail in New Jersey is projected to rise about 361% by 2030 — from 0.11 in 2025 to a central estimate of 0.51 (95% range 0.00–1.1). A 5-year backtest shows a typical error of ±114.7%, with 100% of held-out values landing inside the 95% band.

+361%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 →
0.51Projected 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 →
0.00–1.195% 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 →
±114.7%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 New Jersey is projected to rise about 361% by 2030 — from 0.11 in 2025 to a central estimate of 0.51 (95% range 0.00–1.1). A 5-year backtest shows a typical error of ±114.7%, with 100% of held-out values landing inside the 95% band.19792030
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 →
20260.510.001.1
20270.510.001.1
20280.510.001.1
20290.510.001.1
20300.510.001.1

Clapper Rail Survey Routes in New Jersey

Routes recording Clapper Rail in New Jersey.
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 →
Six Points220191984
Ocean City220251979
Greenwich120011996

Clapper Rail Population Trend in Other States

alabamaconnecticutdelawarefloridageorgialouisianamarylandnew-yorknorth-carolinasouth-carolinatexasvirginia

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