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

Marsh Wren Population Trend in Colorado

All statesForest birds

Marsh Wren in Colorado has fallen sharply: down 66% on the route-weighted index since 1992.

-66%Since 1992
16Routes In State
31Years

Notable Marsh Wren Trends in Colorado

long arc declinecomputed index

Marsh Wren has fallen sharply in Colorado: down 66% on the route-weighted index since 1992.

Marsh Wren Population Forecast in Colorado

If the recent trend holds, Marsh Wren in Colorado is projected to fall about 100% by 2029 — from 0.06 in 2024 to a central estimate of 0.00 (95% range 0.00–0.21). A 5-year backtest shows a typical error of ±204.9%, with 100% of held-out values landing inside the 95% band.

-100%Change by 2029
0.00Projected 2029 index
0.00–0.2195% range
±204.9%Backtest error
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 index95% low95% high
20250.000.000.21
20260.000.000.21
20270.000.000.21
20280.000.000.21
20290.000.000.21

Marsh Wren Survey Routes in Colorado

Routes recording Marsh Wren in Colorado.
Arsenal520021991
Yellowjacket Pass320182018
Maybell320241992
Walden320242010
Moffat319951993
Alamosa320171989
Paonia320032003
San Luis320001991
Hudson220151994
Browns Park220211995
Lay220122009
Marshall Pas220121998
Dinosaur120122012
Doyleville120222022
Cortez120071997
Angora120222022

Marsh Wren Population Trend in Other States

alabamaarizonacaliforniaconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaslouisianamainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatexasutahvermontvirginiawashingtonwisconsinwyoming

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