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

Bullock's Oriole In Sierra Nevada

All regionsSierra NevadaForest birds

Bullock's Oriole in Sierra Nevada has fallen sharply: down 59% on the route-weighted index since 1971.

-59%Since 1971TrendPercent 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 →
25Routes 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 →
56YearsYears 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 →

Bullock's Oriole has fallen sharply in Sierra Nevada: down 59% on the route-weighted index since 1971.

Bullock's Oriole In Sierra Nevada Population Forecast

If the recent trend holds, Bullock's Oriole in Sierra Nevada is projected to fall about 79% by 2030 — from 1.4 in 2025 to a central estimate of 0.30 (95% range 0.00–2.3). A 5-year backtest shows a typical error of ±53.1%, with 100% of held-out values landing inside the 95% band.

-79%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 →
0.30Projected 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 →
0.00–2.395% 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 →
±53.1%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, Bullock's Oriole in Sierra Nevada is projected to fall about 79% by 2030 — from 1.4 in 2025 to a central estimate of 0.30 (95% range 0.00–2.3). A 5-year backtest shows a typical error of ±53.1%, with 100% of held-out values landing inside the 95% band.19692030
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 →
20260.470.002.5
20270.430.002.5
20280.390.002.4
20290.340.002.4
20300.300.002.3

Routes In Sierra Nevada

Routes recording Bullock's Oriole 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 →
KernvilleCALIFORNIA282008
Greenhorn MtCALIFORNIA242008
PaxtonCALIFORNIA152025
ChilcootCALIFORNIA92024
Bass LakeCALIFORNIA62018
Silver CityCALIFORNIA42013
WawonaCALIFORNIA32025
Cottage SpgsCALIFORNIA21975
Kings CanyonCALIFORNIA22013
SattleyCALIFORNIA22025
GeneseeCALIFORNIA22024
RivertonCALIFORNIA22014
ChesterCALIFORNIA22013
Forest HillCALIFORNIA22025
Lassen ParkCALIFORNIA11981
Eagle LakeCALIFORNIA11986
WestvilleCALIFORNIA12001
WoodfordsCALIFORNIA12025
Tuolumne GroveCALIFORNIA12018
Higgins CornCALIFORNIA12025
DownievilleCALIFORNIA12025
LakeshoreCALIFORNIA12014
Tahoe NfCALIFORNIA11993
PlacervilleCALIFORNIA12025
CoultervilleCALIFORNIA12013

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