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Species · BCR 2 · BBS 2026 Release · 1966–2025

Ruby-crowned Kinglet In BCR 2

All regionsBCR 2Forest birds

Ruby-crowned Kinglet in BCR 2 has fallen sharply: down 69% on the route-weighted index since 1993.

-69%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 →
27YearsYears 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 69% 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 fall about 44% by 2030 — from 0.67 in 2025 to a central estimate of 0.37 (95% range 0.00–4.4). A 5-year backtest shows a typical error of ±113.4%, with 100% of held-out values landing inside the 95% band.

-44%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 →
0.37Projected 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 →
0.00–4.495% 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 →
±113.4%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 fall about 44% by 2030 — from 0.67 in 2025 to a central estimate of 0.37 (95% range 0.00–4.4). A 5-year backtest shows a typical error of ±113.4%, with 100% of held-out values landing inside the 95% band.19842030
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 →
20260.550.004.6
20270.500.004.6
20280.460.004.5
20290.420.004.5
20300.370.004.4

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.ALASKA42025
King SalmonALASKA12019
St. Mary'SALASKA11998
Gweek RiverALASKA12002
Selawik (Short)ALASKA11987

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