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

Clapper Rail Population Trend in Maryland

All statesWetland birds

Clapper Rail in Maryland has surged: up 14× on the route-weighted index since 1969.

14×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 →
5Routes 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 MarylandNotable 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 Clapper Rail in Maryland. See the full index history below.

Clapper Rail Population Forecast in Maryland

If the recent trend holds, Clapper Rail in Maryland is projected to rise about 12% by 2030 — from 0.32 in 2025 to a central estimate of 0.35 (95% range 0.19–0.51). A 5-year backtest shows a typical error of ±19.7%, with 80% of held-out values landing inside the 95% band.

+12%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 →
0.35Projected 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 →
0.19–0.5195% 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 →
±19.7%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 Maryland is projected to rise about 12% by 2030 — from 0.32 in 2025 to a central estimate of 0.35 (95% range 0.19–0.51). A 5-year backtest shows a typical error of ±19.7%, with 80% of held-out values landing inside the 95% band.19672030
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 →
20260.330.170.49
20270.340.180.50
20280.340.180.50
20290.350.190.51
20300.350.190.51

Clapper Rail Survey Routes in Maryland

Routes recording Clapper Rail in Maryland.
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 →
Honga720251967
Madison420251972
Berlin219861981
Melitota119951995
Cokesbury120252014

Clapper Rail Population Trend in Other States

alabamaconnecticutdelawarefloridageorgialouisiananew-jerseynew-yorknorth-carolinasouth-carolinatexasvirginia

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