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Species · BCR 2 · BBS 2025 Release · 1966–2024

Ruby-crowned Kinglet In BCR 2

All regionsBCR 2Forest birds

Ruby-crowned Kinglet in BCR 2 has fallen sharply: down 61% on the route-weighted index since 1993.

-61%Since 1993TrendPercent 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 RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
26YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable 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 →

Ruby-crowned Kinglet has fallen sharply in BCR 2: down 61% on the route-weighted index since 1993.

Ruby-crowned Kinglet In BCR 2 Population Forecast

If the recent trend holds, Ruby-crowned Kinglet in BCR 2 is projected to rise about 70% by 2027 — from 0.29 in 2022 to a central estimate of 0.49 (95% range 0.00–4.6). A 5-year backtest shows a typical error of ±163.1%, with 100% of held-out values landing inside the 95% band.

+70%Change by 2027TrendPercent 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 →
0.49Projected 2027 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–4.695% 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 →
±163.1%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 BCR 2 is projected to rise about 70% by 2027 — from 0.29 in 2022 to a central estimate of 0.49 (95% range 0.00–4.6). A 5-year backtest shows a typical error of ±163.1%, with 100% of held-out values landing inside the 95% band.19842027
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 →
20230.670.004.8
20240.620.004.8
20250.580.004.7
20260.530.004.7
20270.490.004.6

Routes In BCR 2

Routes recording Ruby-crowned Kinglet in BCR 2.
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 →
Dillingham (Short)ALASKA331984
DillinghamALASKA292019
Katmai N.P.ALASKA22022
King SalmonALASKA12019
St. Mary'SALASKA11998
Gweek RiverALASKA12002
Selawik (Short)ALASKA11987

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