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

Aerial Insectivores In California

All statesCalifornia

24 species in this guild. As a group they are -18%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 aerial insectivores in California. See the full index history below.

Forecast

If the recent trend holds, Aerial insectivores in California is projected to stay roughly flat through 2029, near 4.4 (95% range 2.9–5.9). A 5-year backtest shows a typical error of ±35.9%, with 60% of held-out values landing inside the 95% band.

+7%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 →
4.4Projected 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 →
2.9–5.995% 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 →
±35.9%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, Aerial insectivores in California is projected to stay roughly flat through 2029, near 4.4 (95% range 2.9–5.9). A 5-year backtest shows a typical error of ±35.9%, with 60% 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 →
20254.53.06.0
20264.53.05.9
20274.53.05.9
20284.43.05.9
20294.42.95.9

Member Species In California

Aerial insectivores 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 →
Violet-green SwallowHirundinidae-62%
Purple MartinHirundinidae-57%
White-throated SwiftApodidae-57%
Olive-sided FlycatcherTyrannidae-56%
Northern Rough-winged SwallowHirundinidae-54%
Willow FlycatcherTyrannidae-52%
Common PoorwillCaprimulgidae-43%
Vaux's SwiftApodidae-37%
Black SwiftApodidae-30%
Lesser NighthawkCaprimulgidae-23%
Western Wood-PeweeTyrannidae-22%
Cliff SwallowHirundinidae-14%
Western KingbirdTyrannidae+7%
Ash-throated FlycatcherTyrannidae+59%
Tree SwallowHirundinidae+63%
Say's PhoebeTyrannidae+66%
Barn SwallowHirundinidae+90%
Common NighthawkCaprimulgidae+214%
Cassin's KingbirdTyrannidae+223%
Dusky FlycatcherTyrannidae+245%
Black PhoebeTyrannidae+283%
Hammond's FlycatcherTyrannidae+493%
Bank SwallowHirundinidae+505%
Gray FlycatcherTyrannidae13×

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