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

Gray Vireo Population Trend in Arizona

All statesForest birds

Gray Vireo in Arizona has edged up: up 12% on the route-weighted index since 1970.

+12%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 →
24Routes 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 Gray Vireo Trends in ArizonaNotable 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 Arizona. See the full index history below.

Gray Vireo Population Forecast in Arizona

If the recent trend holds, Gray Vireo in Arizona is projected to rise about 16% by 2029 — from 0.86 in 2024 to a central estimate of 1.00 (95% range 0.43–1.6). A 5-year backtest shows a typical error of ±96.8%, with 80% of held-out values landing inside the 95% band.

+16%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 →
1.00Projected 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 →
0.43–1.695% 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 →
±96.8%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, Gray Vireo in Arizona is projected to rise about 16% by 2029 — from 0.86 in 2024 to a central estimate of 1.00 (95% range 0.43–1.6). A 5-year backtest shows a typical error of ±96.8%, 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 →
20250.950.381.5
20260.960.401.5
20270.970.411.5
20280.980.421.5
20291.000.431.6

Gray Vireo Survey Routes in Arizona

Routes recording Gray Vireo in Arizona.
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 →
House Rock1120221968
Toroweap1120241994
Carr Mtn820241987
The Gap619731971
Peach Spring620242005
Mormon Lake419681968
Forest Lakes420241995
Aztec Peak319781974
Cutter319961996
Redington320221994
Rose Wells219691969
Tonto Vill.220211994
Navajo Trail220212003
Seligman220232007
Mt Trumbull119751975
Black Mesa119931991
Blue119841976
Page120192006
Cow Springs120222000
Maine119971997
Skull Valley120241996
Bartlett Res120192000
Tsaile120232018
Clay Spring120101989

Gray Vireo Population Trend in Other States

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