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

Yellow-eyed Junco Population Trend in Arizona

All statesGeneralists

Yellow-eyed Junco in Arizona has surged: up 209% on the route-weighted index since 1976.

+209%Since 1976TrendPercent 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 →
7Routes 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 →
43YearsYears 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-eyed Junco 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-eyed Junco has surged in Arizona: up 209% on the route-weighted index since 1976.

Yellow-eyed Junco Population Forecast in Arizona

If the recent trend holds, Yellow-eyed Junco in Arizona is projected to rise about 646% by 2029 — from 0.34 in 2024 to a central estimate of 2.6 (95% range 0.00–5.1). A 5-year backtest shows a typical error of ±359%, with 60% of held-out values landing inside the 95% band.

+646%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 →
2.6Projected 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 →
0.00–5.195% 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 →
±359%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-eyed Junco in Arizona is projected to rise about 646% by 2029 — from 0.34 in 2024 to a central estimate of 2.6 (95% range 0.00–5.1). A 5-year backtest shows a typical error of ±359%, with 60% of held-out values landing inside the 95% band.19742029
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 →
20252.40.005.0
20262.50.005.0
20272.50.005.1
20282.50.005.1
20292.60.005.1

Yellow-eyed Junco Survey Routes in Arizona

Routes recording Yellow-eyed Junco 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 →
Mt. Graham3520231995
Portal1220241975
Sunizona419791979
Rucker420091993
Carr Mtn220142001
Sunizona 2120062006
Aztec Peak119741974

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