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

Warbling Vireo In Sierra Nevada

All regionsSierra NevadaForest birds

Warbling Vireo in Sierra Nevada has surged: up 94% on the route-weighted index since 1971.

+94%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 →
40Routes 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 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 →

Warbling Vireo has surged in Sierra Nevada: up 94% on the route-weighted index since 1971.

Warbling Vireo In Sierra Nevada Population Forecast

If the recent trend holds, Warbling Vireo in Sierra Nevada is projected to rise about 48% by 2030 — from 6.8 in 2025 to a central estimate of 10 (95% range 6.6–14). A 5-year backtest shows a typical error of ±26.1%, with 100% of held-out values landing inside the 95% band.

+48%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 →
10Projected 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 →
6.6–1495% 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 →
±26.1%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, Warbling Vireo in Sierra Nevada is projected to rise about 48% by 2030 — from 6.8 in 2025 to a central estimate of 10 (95% range 6.6–14). A 5-year backtest shows a typical error of ±26.1%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20269.86.313
20279.96.313
202810.06.414
2029106.514
2030106.614

Routes In Sierra Nevada

Routes recording Warbling Vireo 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 →
GeneseeCALIFORNIA242024
JohnsvilleCALIFORNIA172025
WoodfordsCALIFORNIA172025
RivertonCALIFORNIA152025
Tuolumne GroveCALIFORNIA132025
Meadow ValleyCALIFORNIA132025
Cottage SpgsCALIFORNIA111968
DardanelleCALIFORNIA112019
Butte MeadowCALIFORNIA102014
Little TruckeeCALIFORNIA102025
StrawberryCALIFORNIA102019
Higgins CornCALIFORNIA92021
WestvilleCALIFORNIA82025
LumberyardCALIFORNIA82025
Kings CanyonCALIFORNIA82024
Tahoe NfCALIFORNIA81994
LakeshoreCALIFORNIA72024
GoumazCALIFORNIA62011
Eagle LakeCALIFORNIA52025
Chaos CraterCALIFORNIA52019
PaxtonCALIFORNIA42025
Pollock PinesCALIFORNIA42025
PlacervilleCALIFORNIA42025
Pine MountainCALIFORNIA42017
Bass LakeCALIFORNIA32011

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