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Species · Arizona · BBS 2025 Release · 1966–2024

Warbling Vireo Population Trend in Arizona

All statesForest birds

Warbling Vireo in Arizona has surged: up 14× on the route-weighted index since 1974.

14×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 →
28Routes 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 →
52YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Warbling 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 →

long arc increasecomputed 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 →

Warbling Vireo has surged in Arizona: up 14× on the route-weighted index since 1974.

Warbling Vireo Population Forecast in Arizona

If the recent trend holds, Warbling Vireo in Arizona is projected to rise about 43% by 2029 — from 2.8 in 2024 to a central estimate of 4.0 (95% range 2.2–5.8). A 5-year backtest shows a typical error of ±18.2%, with 100% of held-out values landing inside the 95% band.

+43%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 →
4.0Projected 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 →
2.2–5.895% 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 →
±18.2%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, Warbling Vireo in Arizona is projected to rise about 43% by 2029 — from 2.8 in 2024 to a central estimate of 4.0 (95% range 2.2–5.8). A 5-year backtest shows a typical error of ±18.2%, 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 →
20253.82.05.6
20263.82.05.7
20273.92.15.7
20283.92.15.8
20294.02.25.8

Warbling Vireo Survey Routes in Arizona

Routes recording Warbling 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 →
Dry Park9320241992
Mt. Graham4020231995
Alpine2820231995
Tsaile1920231996
Prescott1120221976
Aztec Peak719781974
Sawmill520101996
Sprucedale520211992
Flagstaff420221988
Blue319911974
Skull Valley320241996
Portal220231979
Dragoon220091996
Patagonia220101997
Maine219971997
Carr Mtn220191985
Black Mesa119951995
Rucker120061995
Mormon Lake119741968
Pomerene120221976
San Simon119791979
Sunizona119741974
Tonto Vill.120152008
Forest Lakes120241994
Pinetop120222022

Warbling Vireo Population Trend in Other States

alabamaalaskaarkansascaliforniacoloradoconnecticutdelawareidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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