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

Black-chinned Sparrow Population Trend in Arizona

All statesGeneralists

Black-chinned Sparrow in Arizona has collapsed: down 79% on the route-weighted index since 1974.

-79%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 →
16Routes 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 Black-chinned Sparrow 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 declinecomputed 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-chinned Sparrow has collapsed in Arizona: down 79% on the route-weighted index since 1974.

Black-chinned Sparrow Population Forecast in Arizona

If the recent trend holds, Black-chinned Sparrow in Arizona is projected to rise about 94% by 2029 — from 0.20 in 2024 to a central estimate of 0.39 (95% range 0.00–0.97). A 5-year backtest shows a typical error of ±348.9%, with 100% of held-out values landing inside the 95% band.

+94%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 →
0.39Projected 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 →
0.00–0.9795% 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 →
±348.9%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, Black-chinned Sparrow in Arizona is projected to rise about 94% by 2029 — from 0.20 in 2024 to a central estimate of 0.39 (95% range 0.00–0.97). A 5-year backtest shows a typical error of ±348.9%, with 100% of held-out values landing inside the 95% band.19712029
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 →
20250.410.000.99
20260.400.000.98
20270.400.000.98
20280.390.000.97
20290.390.000.97

Black-chinned Sparrow Survey Routes in Arizona

Routes recording Black-chinned Sparrow 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 →
Aztec Peak1719781974
Cutter720141992
Carr Mtn320241985
Mt Trumbull219791979
Skull Valley220241996
Rucker219991999
Toroweap220211995
Patagonia119871981
House Rock120132013
The Gap119731971
Tonto Vill.120211994
Portal120241983
Bartlett Res120241993
Dragoon119951995
Prescott120221974
Sahuarita120191992

Black-chinned Sparrow Population Trend in Other States

californianevadanew-mexicotexasutah

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