BirdAnalyst
Species · BCR 15 · BBS 2026 Release · 1966–2025

Orange-crowned Warbler In Sierra Nevada

All regionsSierra NevadaForest birds

Orange-crowned Warbler in Sierra Nevada has edged down: down 23% on the route-weighted index since 1973.

-23%Since 1973TrendPercent 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 →
34Routes 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 →
54YearsYears 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 →

No notable trend signals for Orange-crowned Warbler in Sierra Nevada. See the full index history below.

Orange-crowned Warbler In Sierra Nevada Population Forecast

If the recent trend holds, Orange-crowned Warbler in Sierra Nevada is projected to rise about 21% by 2030 — from 1.4 in 2025 to a central estimate of 1.7 (95% range 0.00–4.0). A 5-year backtest shows a typical error of ±18.8%, with 100% of held-out values landing inside the 95% band.

+21%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 →
1.7Projected 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 →
0.00–4.095% 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 →
±18.8%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, Orange-crowned Warbler in Sierra Nevada is projected to rise about 21% by 2030 — from 1.4 in 2025 to a central estimate of 1.7 (95% range 0.00–4.0). A 5-year backtest shows a typical error of ±18.8%, with 100% of held-out values landing inside the 95% band.19712030
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 →
20261.80.004.0
20271.80.004.0
20281.80.004.0
20291.80.004.0
20301.70.004.0

Routes In Sierra Nevada

Routes recording Orange-crowned Warbler in Sierra Nevada.
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 →
ChilcootCALIFORNIA222009
Higgins CornCALIFORNIA122025
Forest Hill 2CALIFORNIA82005
Forest HillCALIFORNIA52025
PlacervilleCALIFORNIA52025
WawonaCALIFORNIA52024
Tahoe NfCALIFORNIA41994
Lassen ParkCALIFORNIA21987
Tuolumne GroveCALIFORNIA22025
Butte MeadowCALIFORNIA21996
Hat CreekCALIFORNIA22016
LakeshoreCALIFORNIA22024
Chaos CraterCALIFORNIA22003
PaxtonCALIFORNIA22021
Meadow ValleyCALIFORNIA22019
Pine MountainCALIFORNIA22015
Last ChanceCALIFORNIA22018
Eagle LakeCALIFORNIA12014
WestvilleCALIFORNIA12025
DardanelleCALIFORNIA12017
Bass LakeCALIFORNIA12018
JohnsvilleCALIFORNIA12023
WoodfordsCALIFORNIA12019
LumberyardCALIFORNIA12025
Greenhorn MtCALIFORNIA11995

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