BirdAnalyst
Species · California · BBS 2026 Release · 1966–2025

Northern House Wren Population Trend in California

All statesForest birds

Northern House Wren in California has increased: up 26% on the route-weighted index since 1970.

+26%Since 1970TrendPercent 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 →
209Routes 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 →
57YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Northern House Wren Trends in CaliforniaNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Northern House Wren in California. See the full index history below.

Northern House Wren Population Forecast in California

If the recent trend holds, Northern House Wren in California is projected to rise about 68% by 2030 — from 2.2 in 2025 to a central estimate of 3.8 (95% range 1.4–6.1). A 5-year backtest shows a typical error of ±64.7%, with 100% of held-out values landing inside the 95% band.

+68%Change by 2030TrendPercent 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 →
3.8Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
1.4–6.195% 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 →
±64.7%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, Northern House Wren in California is projected to rise about 68% by 2030 — from 2.2 in 2025 to a central estimate of 3.8 (95% range 1.4–6.1). A 5-year backtest shows a typical error of ±64.7%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20263.71.46.1
20273.81.46.1
20283.81.46.1
20293.81.46.1
20303.81.46.1

Northern House Wren Survey Routes in California

Routes recording Northern House Wren in California.
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 →
White River8019921972
Cal Hot Spgs6720191993
Iron Gate3320191988
El Toro3219991973
Yokohl Val2919971973
Carmel Val2920251973
Santa Ynez2820191969
Lake Success2819961972
Jackson2119921972
Poway2019801973
Crowder Flat1920192002
Fallsvale1819811970
Cleveland Nf1720181994
Harbor Lake 21720242016
Mesa Grande1620251970
Cp. Pendleton1520031971
Macdoel1520191973
Jofegan 21420252024
Genesee1420241972
Foster Park1319941968
Mt Baldy1320241970
Horse Creek1220191970
Hackamore1220102000
Pilot Creek1119961994
Lake Hemet1019861971

Northern House Wren Population Trend in Other States

alabamaarizonaarkansascoloradoconnecticutdelawaregeorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.