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Species · California · BBS 2025 Release · 1966–2024

Olive-sided Flycatcher Population Trend in California

All statesAerial insectivores

Olive-sided Flycatcher in California has fallen sharply: down 56% on the route-weighted index since 1970.

-56%Since 1970
158Routes In State
56Years

Notable Olive-sided Flycatcher Trends in California

long arc declinecomputed index

Olive-sided Flycatcher has fallen sharply in California: down 56% on the route-weighted index since 1970.

Olive-sided Flycatcher Population Forecast in California

If the recent trend holds, Olive-sided Flycatcher in California is projected to fall about 23% by 2029 — from 1.8 in 2024 to a central estimate of 1.3 (95% range 0.62–2.1). A 5-year backtest shows a typical error of ±23%, with 80% of held-out values landing inside the 95% band.

-23%Change by 2029
1.3Projected 2029 index
0.62–2.195% range
±23%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
20251.50.762.2
20261.50.732.2
20271.40.692.1
20281.40.662.1
20291.30.622.1

Olive-sided Flycatcher Survey Routes in California

Routes recording Olive-sided Flycatcher in California.
Waterman Gap2620241972
Cottage Spgs2519751968
Macdoel2320191972
Genesee2320241972
Lassen Park2019891972
Eagle Lake1720241969
Carrville1619701970
French Gulch1520102002
Hat Creek1420181973
Pescadero1320241992
Mt Pinos1220041969
Valyermo1220191970
Tahoe Nf1219941987
Last Chance1220191993
San Benito Mtn.1120092003
Point Reyes1020231970
Westville920241971
Johnsville920241975
Pilot Creek919961994
Mt Pinos 2820242005
Bartle820211972
Hay Fork820172001
Fairfax720241972
Elizabeth Lk719911975
Pollock Pines720241997

Olive-sided Flycatcher Population Trend in Other States

alaskaarizonacoloradoidahomainemarylandmassachusettsmichiganminnesotamontananevadanew-hampshirenew-mexiconew-yorknorth-carolinaohiooregonpennsylvaniasouth-dakotautahvermontwashingtonwest-virginiawisconsinwyoming

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