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Species · California · BBS 2025 Release · 1966–2024

Violet-green Swallow Population Trend in California

All statesAerial insectivores

Violet-green Swallow in California has fallen sharply: down 62% on the route-weighted index since 1970.

-62%Since 1970
184Routes In State
56Years

Notable Violet-green Swallow Trends in California

long arc declinecomputed index

Violet-green Swallow has fallen sharply in California: down 62% on the route-weighted index since 1970.

Violet-green Swallow Population Forecast in California

If the recent trend holds, Violet-green Swallow in California is projected to fall about 49% by 2029 — from 3.0 in 2024 to a central estimate of 1.5 (95% range 0.00–4.0). A 5-year backtest shows a typical error of ±44.1%, with 100% of held-out values landing inside the 95% band.

-49%Change by 2029
1.5Projected 2029 index
0.00–4.095% range
±44.1%Backtest error
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 index95% low95% high
20252.00.004.5
20261.90.004.3
20271.80.004.2
20281.70.004.1
20291.50.004.0

Violet-green Swallow Survey Routes in California

Routes recording Violet-green Swallow in California.
Arvin17219881982
Big Bear8219861969
Lake Hemet6319861970
Riovista5720221992
Fairfax4720241972
Carmel Val4120241973
Valyermo4120191970
Tres Pinos 23920112005
Fallsvale3319811970
White River2419921972
Point Reyes2320231970
Glenn2219911985
Glen Ellen2220041972
Lockwood2020241972
Fish Rock1820141968
Adelaida1820241970
Ingalls1719731973
Folsom1720241984
Imperial Dam1619861978
Cal Hot Spgs1620191993
Santa Ynez1520191969
Coyote1320241972
Forest Hill 21120052005
Auburn1119801969
Likely1120191973

Violet-green Swallow Population Trend in Other States

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