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

Yellow Warbler Population Trend in Arizona

All statesForest birds

Yellow Warbler in Arizona has surged: up 379% on the route-weighted index since 1970.

+379%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 →
43Routes 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 →
55YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Yellow Warbler 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 →

Yellow Warbler has surged in Arizona: up 378% on the route-weighted index since 1970.

Yellow Warbler Population Forecast in Arizona

If the recent trend holds, Yellow Warbler in Arizona is projected to stay roughly flat through 2029, near 1.1 (95% range 0.70–1.5). A 5-year backtest shows a typical error of ±32.9%, with 80% of held-out values landing inside the 95% band.

-7%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 →
1.1Projected 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 →
0.70–1.595% 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 →
±32.9%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, Yellow Warbler in Arizona is projected to stay roughly flat through 2029, near 1.1 (95% range 0.70–1.5). A 5-year backtest shows a typical error of ±32.9%, 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 →
20251.00.641.4
20261.10.651.4
20271.10.671.5
20281.10.681.5
20291.10.701.5

Yellow Warbler Survey Routes in Arizona

Routes recording Yellow Warbler 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 →
Cutter 23520182015
Cutter2020141996
Pomerene1220241968
Patagonia920241969
Carr Mtn520241986
Palo Verde 2420242014
Skull Valley420241996
Dateland320161990
Red Rock 2320192015
Antares320182002
Redington320231994
Cactus Forest320122005
Quartzsite220242001
New River220161998
Blue219891974
Alamo Res.220192003
Pinetop219931993
Bartlett Res220241992
Araby220062004
Casa Grande220231989
Dragoon119961995
Portal120222014
Prescott120221979
Hunt119761976
Florence119881988

Yellow Warbler Population Trend in Other States

alabamaalaskaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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