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Species · BCR 16 · BBS 2025 Release · 1966–2024

Marsh Wren In Southern Rockies / Colorado Plateau

All regionsSouthern Rockies / Colorado PlateauForest birds

Marsh Wren in Southern Rockies / Colorado Plateau has fallen sharply: down 70% on the route-weighted index since 1992.

-70%Since 1992TrendPercent 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 →
16Routes 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 →
32YearsYears 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 fallen sharply in Southern Rockies / Colorado Plateau: down 70% on the route-weighted index since 1992.

Marsh Wren In Southern Rockies / Colorado Plateau Population Forecast

If the recent trend holds, Marsh Wren in Southern Rockies / Colorado Plateau is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.14). A 5-year backtest shows a typical error of ±192%, 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 →
0.00–0.1495% 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 →
±192%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 Southern Rockies / Colorado Plateau is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.14). A 5-year backtest shows a typical error of ±192%, with 100% of held-out values landing inside the 95% band.19892029
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 →
20250.000.000.14
20260.000.000.14
20270.000.000.14
20280.000.000.14
20290.000.000.14

Routes In Southern Rockies / Colorado Plateau

Routes recording Marsh Wren in Southern Rockies / Colorado Plateau.
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 →
MoffatCOLORADO31995
WaldenCOLORADO32024
AlamosaCOLORADO32017
San LuisCOLORADO32000
PaoniaCOLORADO32003
Yellowjacket PassCOLORADO32018
BicknellUTAH32013
Marshall PasCOLORADO22012
DoylevilleCOLORADO12022
CortezCOLORADO12007
DinosaurCOLORADO12012
AngoraCOLORADO12022
BoulderUTAH12006
Castle DaleUTAH12023
HatchUTAH12011
KamasUTAH11997

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