BirdAnalyst
Species · BCR 9 · BBS 2025 Release · 1966–2024

Gray Vireo In Great Basin

All regionsGreat BasinForest birds

Gray Vireo in Great Basin has surged: up 192% on the route-weighted index since 1998.

+192%Since 1998TrendPercent 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 →
10Routes 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 →
25YearsYears 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 →

Gray Vireo has surged in Great Basin: up 192% on the route-weighted index since 1998.

Gray Vireo In Great Basin Population Forecast

If the recent trend holds, Gray Vireo in Great Basin is projected to rise about 51% by 2029 — from 0.09 in 2024 to a central estimate of 0.13 (95% range 0.03–0.23). A 5-year backtest shows a typical error of ±42.6%, with 80% of held-out values landing inside the 95% band.

+51%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 →
0.13Projected 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 →
0.03–0.2395% 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 →
±42.6%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, Gray Vireo in Great Basin is projected to rise about 51% by 2029 — from 0.09 in 2024 to a central estimate of 0.13 (95% range 0.03–0.23). A 5-year backtest shows a typical error of ±42.6%, with 80% of held-out values landing inside the 95% band.19962029
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 →
20250.110.020.21
20260.120.020.21
20270.120.030.22
20280.130.030.22
20290.130.030.23

Routes In Great Basin

Routes recording Gray 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 →
BerylUTAH92024
NewcastleUTAH42022
VernonUTAH22024
WillisNEVADA12021
Comins LakeNEVADA12013
Meadow VallyNEVADA12024
Gold HillUTAH12023
Indian PeakUTAH12006
Jericho JunctionUTAH12023
Tule ValleyUTAH12012

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