BirdAnalyst
Species · BCR 33 · BBS 2025 Release · 1966–2024

Warbling Vireo In Sonoran and Mojave Deserts

All regionsSonoran and Mojave DesertsForest birds

Warbling Vireo in Sonoran and Mojave Deserts has fallen sharply: down 51% on the route-weighted index since 1980.

-51%Since 1980TrendPercent 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 →
9Routes 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 →
19YearsYears 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 →

Warbling Vireo has fallen sharply in Sonoran and Mojave Deserts: down 51% on the route-weighted index since 1980.

Forecast

If the recent trend holds, Warbling Vireo in Sonoran and Mojave Deserts is projected to stay roughly flat through 2029, near 0.01 (95% range 0.00–0.17). A 5-year backtest shows a typical error of ±72.1%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.01Projected 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 →
0.00–0.1795% 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 →
±72.1%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 Sonoran and Mojave Deserts is projected to stay roughly flat through 2029, near 0.01 (95% range 0.00–0.17). A 5-year backtest shows a typical error of ±72.1%, with 100% of held-out values landing inside the 95% band.19712029
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 →
20250.020.000.18
20260.020.000.17
20270.020.000.17
20280.020.000.17
20290.010.000.17

Routes In Sonoran and Mojave Deserts

Routes recording Warbling Vireo in Sonoran and Mojave Deserts.
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 →
Anza BorregoCALIFORNIA61990
Kelso ValleyCALIFORNIA22015
OnyxCALIFORNIA11998
LenwoodCALIFORNIA11977
TecopaCALIFORNIA11982
PearblossomCALIFORNIA11997
Lone PineCALIFORNIA12024
BeattyNEVADA12007
Ash MeadowsNEVADA12002

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