BirdAnalyst
Species · BCR 32 · BBS 2025 Release · 1966–2024

Lark Sparrow In Coastal California

All regionsCoastal CaliforniaGrassland birds

Lark Sparrow in Coastal California has declined: down 46% on the route-weighted index since 1970.

-46%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 →
103Routes 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 →
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 SignalsNotable 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 Lark Sparrow in Coastal California. See the full index history below.

Lark Sparrow In Coastal California Population Forecast

If the recent trend holds, Lark Sparrow in Coastal California is projected to rise about 33% by 2029 — from 2.5 in 2024 to a central estimate of 3.3 (95% range 0.63–6.0). A 5-year backtest shows a typical error of ±64.3%, with 100% of held-out values landing inside the 95% band.

+33%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 →
3.3Projected 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 →
0.63–6.095% 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 →
±64.3%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, Lark Sparrow in Coastal California is projected to rise about 33% by 2029 — from 2.5 in 2024 to a central estimate of 3.3 (95% range 0.63–6.0). A 5-year backtest shows a typical error of ±64.3%, with 100% 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 →
20253.40.756.1
20263.40.726.0
20273.30.696.0
20283.30.666.0
20293.30.636.0

Routes In Coastal California

Routes recording Lark Sparrow in Coastal 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 →
VentucopaCALIFORNIA412002
White RiverCALIFORNIA341992
Yokohl ValCALIFORNIA211997
Red BluffCALIFORNIA192024
Yolla BollyCALIFORNIA182024
ShafterCALIFORNIA111989
Mt LagunaCALIFORNIA101987
OnoCALIFORNIA92012
MaricopaCALIFORNIA92024
SangerCALIFORNIA82024
JacksonCALIFORNIA81992
Tres Pinos 2CALIFORNIA82011
CordovaCALIFORNIA71979
TomheadCALIFORNIA72011
CoalingaCALIFORNIA62022
FallsvaleCALIFORNIA61980
AtwaterCALIFORNIA62012
TujungaCALIFORNIA52013
Mesa GrandeCALIFORNIA52024
ArvinCALIFORNIA52016
WestleyCALIFORNIA52024
AlamarCALIFORNIA52017
CaruthersCALIFORNIA41987
ParkfieldCALIFORNIA42024
OrlandCALIFORNIA42014

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