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

Forest Birds In California

All statesCalifornia

51 species in this guild. As a group they are +22%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 forest birds in California. See the full index history below.

Forest Birds In California Population Forecast

If the recent trend holds, Forest birds in California is projected to rise about 28% by 2029 — from 1.9 in 2024 to a central estimate of 2.4 (95% range 2.0–2.9). A 5-year backtest shows a typical error of ±32.1%, with 0% of held-out values landing inside the 95% band.

+28%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 →
2.4Projected 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 →
2.0–2.995% 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 →
±32.1%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, Forest birds in California is projected to rise about 28% by 2029 — from 1.9 in 2024 to a central estimate of 2.4 (95% range 2.0–2.9). A 5-year backtest shows a typical error of ±32.1%, with 0% 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 →
20252.41.92.9
20262.41.92.9
20272.42.02.9
20282.42.02.9
20292.42.02.9

Member Species In California

Forest birds 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 →
Gray VireoVireonidae-83%
Lewis's WoodpeckerPicidae-75%
Ruby-crowned KingletRegulidae-75%
Varied ThrushTurdidae-65%
Pygmy NuthatchSittidae-65%
Plumbeous VireoVireonidae-63%
Juniper TitmouseParidae-61%
Wilson's WarblerParulidae-57%
Chestnut-backed ChickadeeParidae-46%
Mountain BluebirdTurdidae-31%
Swainson's ThrushTurdidae-19%
Western BluebirdTurdidae-18%
Canyon WrenTroglodytidae+4%
Yellow WarblerParulidae+7%
Townsend's SolitaireTurdidae+11%
Hermit ThrushTurdidae+11%
Bewick's WrenTroglodytidae+14%
Hutton's VireoVireonidae+17%
Ladder-backed WoodpeckerPicidae+18%
Northern House WrenTroglodytidae+24%
Orange-crowned WarblerParulidae+32%
American RobinTurdidae+33%
Downy WoodpeckerPicidae+33%
Warbling VireoVireonidae+34%
Williamson's SapsuckerPicidae+40%
Mountain ChickadeeParidae+42%
Rock WrenTroglodytidae+46%
Oak TitmouseParidae+48%
Nuttall's WoodpeckerPicidae+49%
Acorn WoodpeckerPicidae+54%
California GnatcatcherPolioptilidae+58%
White-breasted NuthatchSittidae+66%
Black-throated Gray WarblerParulidae+87%
White-headed WoodpeckerPicidae+117%
Black-capped ChickadeeParidae+119%
Hairy WoodpeckerPicidae+134%
Red-breasted SapsuckerPicidae+150%
Black-backed WoodpeckerPicidae+177%
Pileated WoodpeckerPicidae+177%
MacGillivray's WarblerParulidae+219%
Cassin's VireoVireonidae+287%
Brown CreeperCerthiidae+308%
Red-breasted NuthatchSittidae+347%
Pacific WrenTroglodytidae+353%
Nashville WarblerParulidae+435%
Hermit WarblerParulidae+446%
Blue-gray GnatcatcherPolioptilidae+532%
Golden-crowned KingletRegulidae+592%
Bell's VireoVireonidae+725%
Marsh WrenTroglodytidae+811%
Common YellowthroatParulidae+922%

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