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Species · Oregon · BBS 2026 Release · 1966–2025

Cassin's Vireo Population Trend in Oregon

All statesForest birds

Cassin's Vireo in Oregon has edged up: up 24% on the route-weighted index since 1970.

+24%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 →
97Routes 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 →
57YearsYears 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 stay roughly flat through 2030, near 2.0 (95% range 1.3–2.7). A 5-year backtest shows a typical error of ±12.8%, with 100% of held-out values landing inside the 95% band.

-4%Change by 2030TrendPercent 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 →
2.0Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
1.3–2.795% 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 →
±12.8%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 stay roughly flat through 2030, near 2.0 (95% range 1.3–2.7). A 5-year backtest shows a typical error of ±12.8%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20261.91.22.6
20271.91.22.6
20281.91.32.6
20292.01.32.6
20302.01.32.7

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 Creek1720251992
Secret Val1520251975
Wallowa1520252025
Ruch1420231992
Flora1220231986
Hells Canyon1120251992
Chinchalo1120251993
Davis Lake1020252000
Hash Rock920251989
Newbridge920251992
Troy820251992
Unity820252022
Prospect720251993
Silver Creek620251984
Paunina620251993
Lakeview620251999
Sams Valley520251993
Emigrant Lake 2520252002
Ochoco520251993
Donnelly520061994
Derby419931970
Eagle Rock419791971
Camp Sherman419961972
Clearwater420211991
Glasgow419961988

Cassin's Vireo Population Trend in Other States

alaskacaliforniaidahomontanawashington

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.