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Species · Utah · BBS 2025 Release · 1966–2024

Gray Vireo Population Trend in Utah

All statesForest birds

Gray Vireo in Utah has edged up: up 13% on the route-weighted index since 1974.

+13%Since 1974TrendPercent 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 →
45Routes 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 →
44YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Gray Vireo Trends in UtahNotable 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 Gray Vireo in Utah. See the full index history below.

Gray Vireo Population Forecast in Utah

If the recent trend holds, Gray Vireo in Utah is projected to fall about 27% by 2029 — from 1.3 in 2024 to a central estimate of 0.91 (95% range 0.00–1.8). A 5-year backtest shows a typical error of ±34.9%, with 80% of held-out values landing inside the 95% band.

-27%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 →
0.91Projected 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 →
0.00–1.895% 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 →
±34.9%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, Gray Vireo in Utah is projected to fall about 27% by 2029 — from 1.3 in 2024 to a central estimate of 0.91 (95% range 0.00–1.8). A 5-year backtest shows a typical error of ±34.9%, with 80% of held-out values landing inside the 95% band.19692029
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 →
20250.900.001.8
20260.900.001.8
20270.910.001.8
20280.910.001.8
20290.910.001.8

Gray Vireo Survey Routes in Utah

Routes recording Gray Vireo in Utah.
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 →
Shivwitz1920241993
Moquith Mtn1520241988
Beryl920242009
Altonah819691969
Canyonlands820241986
Glen Canyon620241993
Notom520191987
Blanding520242004
Hite420231986
Newcastle420221998
La Sal 3420242008
Escalante320181998
Book Ridge220242013
Arches Np220111989
Boulder220181974
Vernon220242013
Fayette220011994
Richfield220191999
Gooseberry220221999
La Sal219961993
Vernal220042003
Alton220011999
Bullfrog Bay220082005
Fish Lake Nf220192019
Wellington 3120222022

Gray Vireo Population Trend in Other States

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