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

Northern Rough-winged Swallow Population Trend in California

All statesAerial insectivores

Northern Rough-winged Swallow in California has fallen sharply: down 54% on the route-weighted index since 1970.

-54%Since 1970
203Routes In State
56Years

Notable Northern Rough-winged Swallow Trends in California

long arc declinecomputed index

Northern Rough-winged Swallow has fallen sharply in California: down 54% on the route-weighted index since 1970.

Northern Rough-winged Swallow Population Forecast in California

If the recent trend holds, Northern Rough-winged Swallow in California is projected to fall about 24% by 2029 — from 0.95 in 2024 to a central estimate of 0.72 (95% range 0.00–2.6). A 5-year backtest shows a typical error of ±33%, with 100% of held-out values landing inside the 95% band.

-24%Change by 2029
0.72Projected 2029 index
0.00–2.695% range
±33%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
20250.900.002.8
20260.860.002.8
20270.810.002.7
20280.760.002.7
20290.720.002.6

Northern Rough-winged Swallow Survey Routes in California

Routes recording Northern Rough-winged Swallow in California.
Oilfields7720052005
Brawley4820101971
Orland4019921983
Collegeville3220021972
El Toro2319991973
Horse Creek2220191970
Parker Dam1820071973
Bakersfield1720231979
Palo Verde1620241973
Orange Cove1520121972
Coachella Cn1420131977
Blythe1419791973
Elizabeth Lk1420161972
Sisquoc1320141971
Fish Rock1220141969
Jofegan 21120242024
Athlone1120071978
Niland1020241973
Korbel1020211973
Glamis920181973
Havasu Lake920032003
Imperial Dam920101973
Creston920231972
Carrizo Pln920211970
Iron Gate920191988

Northern Rough-winged Swallow Population Trend in Other States

alabamaalaskaarizonaarkansascoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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