BirdAnalyst
Species · BCR 15 · BBS 2025 Release · 1966–2024

Warbling Vireo In Sierra Nevada

All regionsSierra NevadaForest birds

Warbling Vireo in Sierra Nevada has surged: up 97% on the route-weighted index since 1971.

+97%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 →
55YearsYears 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 97% 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 20% by 2029 — from 8.6 in 2024 to a central estimate of 10 (95% range 6.8–14). A 5-year backtest shows a typical error of ±21.3%, with 100% of held-out values landing inside the 95% band.

+20%Change by 2029TrendPercent 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 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
6.8–1495% 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 →
±21.3%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 20% by 2029 — from 8.6 in 2024 to a central estimate of 10 (95% range 6.8–14). A 5-year backtest shows a typical error of ±21.3%, with 100% of held-out values landing inside the 95% band.19682029
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 →
202510.06.514
2026106.614
2027106.614
2028106.714
2029106.814

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 →
Little TruckeeCALIFORNIA252023
GeneseeCALIFORNIA242024
WoodfordsCALIFORNIA202024
RivertonCALIFORNIA172023
Meadow ValleyCALIFORNIA152024
Tuolumne GroveCALIFORNIA142024
JohnsvilleCALIFORNIA132024
Cottage SpgsCALIFORNIA111968
DardanelleCALIFORNIA112019
LumberyardCALIFORNIA112024
WestvilleCALIFORNIA102024
Butte MeadowCALIFORNIA102014
StrawberryCALIFORNIA102019
Higgins CornCALIFORNIA92021
Pollock PinesCALIFORNIA92024
Kings CanyonCALIFORNIA82024
Tahoe NfCALIFORNIA81994
PlacervilleCALIFORNIA82024
Eagle LakeCALIFORNIA72024
LakeshoreCALIFORNIA72024
GoumazCALIFORNIA62011
DownievilleCALIFORNIA52024
Chaos CraterCALIFORNIA52019
PaxtonCALIFORNIA42024
Pine MountainCALIFORNIA42017

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