BirdAnalyst
Species · BCR 27 · BBS 2025 Release · 1966–2024

Marsh Wren In Southeastern Coastal Plain

All regionsSoutheastern Coastal PlainForest birds

Marsh Wren in Southeastern Coastal Plain has collapsed: down 96% on the route-weighted index since 1968.

-96%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 →
15Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
44YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable 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 →

Marsh Wren has collapsed in Southeastern Coastal Plain: down 96% on the route-weighted index since 1968.

Forecast

If the recent trend holds, Marsh Wren in Southeastern Coastal Plain is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.08). A 5-year backtest shows a typical error of ±801.7%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.00Projected 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 →
±801.7%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, Marsh Wren in Southeastern Coastal Plain is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.08). A 5-year backtest shows a typical error of ±801.7%, with 100% of held-out values landing inside the 95% band.19662029
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 →
20250.000.000.08
20260.000.000.08
20270.000.000.08
20280.000.000.08
20290.000.000.08

Routes In Southeastern Coastal Plain

Routes recording Marsh Wren in Southeastern Coastal Plain.
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 →
Dauphin IsALABAMA31989
PungoVIRGINIA31979
Alabama PtALABAMA21973
KellerGEORGIA21982
Johns IsleSOUTH-CAROLINA21976
Kiawah IslandSOUTH-CAROLINA22024
Dauphin Is 2ALABAMA12003
SteinhatcheeFLORIDA11995
St Vincent IFLORIDA12007
Harrietts BlGEORGIA12006
DarienGEORGIA12017
Colonels IslandGEORGIA12017
MerrimonNORTH-CAROLINA11985
Myrtle GroveNORTH-CAROLINA12019
JamestownSOUTH-CAROLINA11970

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