BirdAnalyst
Species · BCR 9 · BBS 2026 Release · 1966–2025

Warbling Vireo In Great Basin

All regionsGreat BasinForest birds

Warbling Vireo in Great Basin has surged: up 213% on the route-weighted index since 1970.

+213%Since 1970TrendPercent 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 →
149Routes 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 →
57YearsYears 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 Great Basin: up 213% on the route-weighted index since 1970.

Warbling Vireo In Great Basin Population Forecast

If the recent trend holds, Warbling Vireo in Great Basin is projected to rise about 40% by 2030 — from 3.4 in 2025 to a central estimate of 4.7 (95% range 3.6–5.8). A 5-year backtest shows a typical error of ±22.4%, with 60% of held-out values landing inside the 95% band.

+40%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 →
4.7Projected 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 →
3.6–5.895% 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 →
±22.4%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, Warbling Vireo in Great Basin is projected to rise about 40% by 2030 — from 3.4 in 2025 to a central estimate of 4.7 (95% range 3.6–5.8). A 5-year backtest shows a typical error of ±22.4%, with 60% 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 →
20264.53.45.6
20274.63.55.7
20284.63.55.7
20294.73.65.8
20304.73.65.8

Routes In Great Basin

Routes recording Warbling Vireo in Great Basin.
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 →
AustinNEVADA372018
KendallWASHINGTON362025
NewhalemWASHINGTON332025
RimrockWASHINGTON312025
Magic MtnIDAHO292025
E. Mt. AdamsWASHINGTON282025
Picture FlatOREGON252025
LakeviewOREGON252025
Blewett PassWASHINGTON252025
Hardware RanchUTAH242023
Oak CityUTAH212024
Silver CityIDAHO202025
Mt HoodOREGON192025
White ChuckWASHINGTON182025
RonaldWASHINGTON162025
MazamaWASHINGTON152022
BartleCALIFORNIA132021
Lake ChelanWASHINGTON132025
No CascadesWASHINGTON132019
MacdoelCALIFORNIA122019
Badger CreekOREGON122025
SnowdenWASHINGTON122025
LeadoreIDAHO112024
SquirrelIDAHO112025
L. WenatcheeWASHINGTON112025

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