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

Olive-sided Flycatcher Population Trend in Washington

All statesAerial insectivores

Olive-sided Flycatcher in Washington has fallen sharply: down 59% on the route-weighted index since 1970.

-59%Since 1970TrendPercent 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 →
76Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
56YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Olive-sided Flycatcher Trends in WashingtonNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

long arc declinecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Olive-sided Flycatcher has fallen sharply in Washington: down 59% on the route-weighted index since 1970.

Olive-sided Flycatcher Population Forecast in Washington

If the recent trend holds, Olive-sided Flycatcher in Washington is projected to fall about 75% by 2029 — from 1.6 in 2024 to a central estimate of 0.40 (95% range 0.00–1.7). A 5-year backtest shows a typical error of ±64.1%, with 100% of held-out values landing inside the 95% band.

-75%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 →
0.40Projected 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 →
0.00–1.795% 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 →
±64.1%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, Olive-sided Flycatcher in Washington is projected to fall about 75% by 2029 — from 1.6 in 2024 to a central estimate of 0.40 (95% range 0.00–1.7). A 5-year backtest shows a typical error of ±64.1%, with 100% 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 →
20250.580.001.9
20260.540.001.8
20270.490.001.8
20280.440.001.7
20290.400.001.7

Olive-sided Flycatcher Survey Routes in Washington

Routes recording Olive-sided Flycatcher in Washington.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
Deer Park1420062002
Warm Beach820171968
Vashon Is.820241995
Spring Lake820241982
Hurricane Rg820241992
Rimrock720241968
Camas620091977
Ilwaco620241975
Snowden520241971
Newhalem420241969
Mcchord420151996
Raymond 2420242022
Packwood420241975
Deception420181992
Cloverland420241993
Port Angeles320241970
Ronald320241973
Mazama320221993
Yakima319961996
Warm Beach 2320242018
Carnation320241989
Montesand220241992
Keller219831968
Chewelah220081977
Index219701968

Olive-sided Flycatcher Population Trend in Other States

alaskaarizonacaliforniacoloradoidahomainemarylandmassachusettsmichiganminnesotamontananevadanew-hampshirenew-mexiconew-yorknorth-carolinaohiooregonpennsylvaniasouth-dakotautahvermontwest-virginiawisconsinwyoming

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