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

Marsh Wren Population Trend in California

All statesForest birds

Marsh Wren in California has surged: up 811% on the route-weighted index since 1972.

+811%Since 1972
48Routes In State
54Years

Notable Marsh Wren Trends in California

long arc increasecomputed index

Marsh Wren has surged in California: up 811% on the route-weighted index since 1972.

Marsh Wren Population Forecast in California

If the recent trend holds, Marsh Wren in California is projected to rise about 25% by 2029 — from 0.87 in 2024 to a central estimate of 1.1 (95% range 0.45–1.7). A 5-year backtest shows a typical error of ±67.3%, with 80% of held-out values landing inside the 95% band.

+25%Change by 2029
1.1Projected 2029 index
0.45–1.795% range
±67.3%Backtest error
19702029
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
20251.10.421.7
20261.10.431.7
20271.10.441.7
20281.10.441.7
20291.10.451.7

Marsh Wren Survey Routes in California

Routes recording Marsh Wren in California.
Dorris7620191972
Staten Is.3320241994
Ora Loma3020241973
Glenn2020231972
Likely620241974
Redwood N.P.520101995
Shafter519891987
Imperial Dam520101977
Redwood N.P. 2420132012
Bodega Bay420211972
Point Reyes420221971
Iron Gate319921992
Honey Lake320241977
Tranquillity320041975
Niland320241973
Cp. Pendleton320031972
Nubieber220181970
Crescent Cty220241972
Arvin219881982
Atwater220121973
Madeline220242010
Westley220141995
Macdoel220191992
Zamora220031987
Coyote219841984

Marsh Wren Population Trend in Other States

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

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