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Species · Arizona · BBS 2026 Release · 1966–2025

Black-throated Gray Warbler Population Trend in Arizona

All statesForest birds

Black-throated Gray Warbler in Arizona has risen sharply: up 71% on the route-weighted index since 1970.

+71%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 →
31Routes 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 Black-throated Gray 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 →

Black-throated Gray Warbler has risen sharply in Arizona: up 71% on the route-weighted index since 1970.

Black-throated Gray Warbler Population Forecast in Arizona

If the recent trend holds, Black-throated Gray Warbler in Arizona is projected to fall about 41% by 2030 — from 2.0 in 2025 to a central estimate of 1.1 (95% range 0.00–2.4). A 5-year backtest shows a typical error of ±50.7%, with 100% of held-out values landing inside the 95% band.

-41%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 →
1.1Projected 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 →
0.00–2.495% 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 →
±50.7%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, Black-throated Gray Warbler in Arizona is projected to fall about 41% by 2030 — from 2.0 in 2025 to a central estimate of 1.1 (95% range 0.00–2.4). A 5-year backtest shows a typical error of ±50.7%, 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 →
20261.20.002.4
20271.20.002.4
20281.20.002.4
20291.10.002.4
20301.10.002.4

Black-throated Gray Warbler Survey Routes in Arizona

Routes recording Black-throated Gray 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 →
Tonto Vill.2820251995
Williams1320252006
Portal1120251975
Carr Mtn920251985
House Rock720221968
Aztec Peak619781974
Sprucedale620251992
Black Mesa519951990
Sunizona519971970
Forest Lakes520251992
Mt. Graham420251996
Tsaile420232017
Rucker320091993
Hunt319761976
Mormon Lake219741974
Cow Springs220221995
Pinetop220212014
Sunizona 2220222001
Round Rock119691969
Dragoon120091995
Flagstaff120091992
Sawmill120082005
Prescott120251974
Blue119911974
Patagonia120191987

Black-throated Gray Warbler Population Trend in Other States

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