BirdAnalyst
Species · Maryland · BBS 2025 Release · 1966–2024

King Rail Population Trend in Maryland

All statesWetland birds

King Rail in Maryland has surged: up 85% on the route-weighted index since 1975.

+85%Since 1975TrendPercent 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 →
25YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable King 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 →

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 →

King Rail has surged in Maryland: up 85% on the route-weighted index since 1975.

King Rail Population Forecast in Maryland

If the recent trend holds, King Rail in Maryland is projected to fall about 55% by 2029 — from 0.10 in 2024 to a central estimate of 0.04 (95% range 0.00–0.08). A 5-year backtest shows a typical error of ±45.8%, with 60% of held-out values landing inside the 95% band.

-55%Change by 2029TrendPercent 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 →
0.04Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.0895% 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 →
±45.8%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 →
19732029
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 →
20250.040.000.08
20260.040.000.08
20270.040.000.08
20280.040.000.08
20290.040.000.08

King Rail Survey Routes in Maryland

Routes recording King 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 →
Honga220241973
Madison220241976
Melitota119741974
Golden Hill119751975
Cokesbury119731973

King Rail Population Trend in Other States

alabamaarkansasconnecticutdelawarefloridageorgiakansaslouisianaminnesotamississippinew-jerseynorth-carolinaoklahomasouth-carolinatexasvirginiawest-virginiawisconsin

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.