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

Northern Mockingbird Population Trend in California

All statesGeneralists

Northern Mockingbird in California has edged up: up 18% on the route-weighted index since 1970.

+18%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 →
186Routes 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 →
56YearsYears 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 Mockingbird 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 Mockingbird in California. See the full index history below.

Northern Mockingbird Population Forecast in California

If the recent trend holds, Northern Mockingbird in California is projected to fall about 37% by 2029 — from 6.5 in 2024 to a central estimate of 4.1 (95% range 1.6–6.7). A 5-year backtest shows a typical error of ±41.7%, with 20% of held-out values landing inside the 95% band.

-37%Change 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 →
4.1Projected 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 →
1.6–6.795% 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 →
±41.7%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 Mockingbird in California is projected to fall about 37% by 2029 — from 6.5 in 2024 to a central estimate of 4.1 (95% range 1.6–6.7). A 5-year backtest shows a typical error of ±41.7%, with 20% of held-out values landing inside the 95% band.19682029
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 →
20254.21.66.7
20264.21.66.7
20274.21.66.7
20284.11.66.7
20294.11.66.7

Northern Mockingbird Survey Routes in California

Routes recording Northern Mockingbird 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 →
Harbor Lake12419911973
S Catalina9220221988
Auburn5019801969
Parkfield4220241968
Moreno4120241968
Gravesboro3819951968
Barstow3819981968
Harbor Lake 23420242014
Westley3320241972
Hughson3220241968
Hollister 22920242012
Collegeville2820041968
Riovista2620241968
Maricopa2520241970
Tres Pinos 22520112005
Greenwater V2420241977
Tranquillity2420241972
Colma2319721968
Haiwee Res2320051975
Oroville2320241972
San Ysidro2220191973
Joshua Tree2220021970
Poway2019801973
Mark West2020241972
Collegeville 22020232007

Northern Mockingbird Population Trend in Other States

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

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