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Species · Oregon · BBS 2025 Release · 1966–2024

Cassin's Vireo Population Trend in Oregon

All statesForest birds

Cassin's Vireo in Oregon has edged up: up 21% on the route-weighted index since 1970.

+21%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 →
95Routes 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 Cassin's Vireo Trends in OregonNotable 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 Cassin's Vireo in Oregon. See the full index history below.

Cassin's Vireo Population Forecast in Oregon

If the recent trend holds, Cassin's Vireo in Oregon is projected to rise about 20% by 2029 — from 1.6 in 2024 to a central estimate of 1.9 (95% range 1.3–2.6). A 5-year backtest shows a typical error of ±14.9%, with 80% of held-out values landing inside the 95% band.

+20%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 →
1.9Projected 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 →
1.3–2.695% 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 →
±14.9%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, Cassin's Vireo in Oregon is projected to rise about 20% by 2029 — from 1.6 in 2024 to a central estimate of 1.9 (95% range 1.3–2.6). A 5-year backtest shows a typical error of ±14.9%, with 80% 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 →
20251.91.22.6
20261.91.22.6
20271.91.22.6
20281.91.22.6
20291.91.32.6

Cassin's Vireo Survey Routes in Oregon

Routes recording Cassin's Vireo in Oregon.
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 →
Badger Creek2120241992
Ruch1420231992
Flora1220231986
Secret Val1120221975
Prospect1120241993
Davis Lake1020242000
Hells Canyon1020221992
Newbridge920241992
Monument920241993
Wizard Falls820241998
Selma820241993
Paunina720241993
Chinchalo620241993
Silver Creek520241984
Donnelly520061994
Wickiup420241969
Derby419931970
Eagle Rock419791971
Camp Sherman419961972
Granite420241993
Clearwater420211991
Glasgow419961988
Troy420241992
Bald Mtn.420241992
Timber320061971

Cassin's Vireo Population Trend in Other States

alaskacaliforniaidahomontanawashington

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