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

Ruby-crowned Kinglet Population Trend in Arizona

All statesForest birds

Ruby-crowned Kinglet in Arizona has surged: up 24× on the route-weighted index since 1975.

24×Since 1975TrendPercent 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 →
15Routes 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 →
49YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Ruby-crowned Kinglet 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 →

Ruby-crowned Kinglet has surged in Arizona: up 24× on the route-weighted index since 1975.

Ruby-crowned Kinglet Population Forecast in Arizona

If the recent trend holds, Ruby-crowned Kinglet in Arizona is projected to rise about 201% by 2029 — from 0.71 in 2024 to a central estimate of 2.2 (95% range 0.98–3.3). A 5-year backtest shows a typical error of ±69.3%, with 80% of held-out values landing inside the 95% band.

+201%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 →
2.2Projected 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 →
0.98–3.395% 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 →
±69.3%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, Ruby-crowned Kinglet in Arizona is projected to rise about 201% by 2029 — from 0.71 in 2024 to a central estimate of 2.2 (95% range 0.98–3.3). A 5-year backtest shows a typical error of ±69.3%, 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 →
20252.00.833.2
20262.00.863.2
20272.10.903.3
20282.10.943.3
20292.20.983.3

Ruby-crowned Kinglet Survey Routes in Arizona

Routes recording Ruby-crowned Kinglet 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 →
Alpine3420231992
Dry Park2520241992
Tsaile2420231993
Maine919971994
Sprucedale820101992
Mt. Graham720231995
House Rock319971995
Blue319911974
Happy Jack220042002
Pinetop120182018
Portal119751975
Flagstaff120131990
Sawmill120141991
Mormon Lake119681968
Williams119931993

Ruby-crowned Kinglet Population Trend in Other States

alaskacaliforniacoloradoidahomainemichiganminnesotamontananevadanew-hampshirenew-mexiconew-yorkoregonsouth-dakotautahvermontwashingtonwisconsinwyoming

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