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

Generalists In California

All statesCalifornia

16 species in this guild. As a group they are -29%Guild trendA mean-index aggregate across the species in this group — the structural direction of the guild, with individual-species noise smoothed out.Full methodology → since 1970.

Guild 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 generalists in California. See the full index history below.

Generalists In California Population Forecast

If the recent trend holds, Generalists in California is projected to fall about 28% by 2030 — from 13 in 2025 to a central estimate of 9.4 (95% range 6.0–13). A 5-year backtest shows a typical error of ±22.2%, with 60% of held-out values landing inside the 95% band.

-28%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 →
9.4Projected 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 →
6.0–1395% 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 →
±22.2%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, Generalists in California is projected to fall about 28% by 2030 — from 13 in 2025 to a central estimate of 9.4 (95% range 6.0–13). A 5-year backtest shows a typical error of ±22.2%, with 60% 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 →
20269.96.513
20279.86.413
20289.66.213
20299.56.113
20309.46.013

Member Species In California

Generalists species in California.
TrendPercent 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 →
Spotted DoveColumbidae-86%
Common Ground DoveColumbidae-73%
Brewer's BlackbirdIcteridae-68%
House SparrowPasseridae-58%
Yellow-billed MagpieCorvidae-35%
House FinchFringillidae-35%
Mourning DoveColumbidae-19%
Northern MockingbirdMimidae+21%
American CrowCorvidae+33%
European StarlingSturnidae+48%
Rock PigeonColumbidae+50%
Brown-headed CowbirdIcteridae+58%
White-winged DoveColumbidae+80%
Common RavenCorvidae+96%
Black-billed MagpieCorvidae+109%
Eurasian Collared-DoveColumbidae94×

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