BirdAnalyst
Species · BCR 34 · BBS 2026 Release · 1966–2025

Warbling Vireo In Sierra Madre Occidental

All regionsSierra Madre OccidentalForest birds

Warbling Vireo in Sierra Madre Occidental has surged: up 186% on the route-weighted index since 1974.

+186%Since 1974TrendPercent 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 →
27Routes 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 →
53YearsYears 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 Madre Occidental: up 186% on the route-weighted index since 1974.

Warbling Vireo In Sierra Madre Occidental Population Forecast

If the recent trend holds, Warbling Vireo in Sierra Madre Occidental is projected to rise about 14% by 2030 — from 2.3 in 2025 to a central estimate of 2.6 (95% range 0.49–4.7). A 5-year backtest shows a typical error of ±88.2%, with 100% of held-out values landing inside the 95% band.

+14%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 →
2.6Projected 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 →
0.49–4.795% 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 →
±88.2%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 Madre Occidental is projected to rise about 14% by 2030 — from 2.3 in 2025 to a central estimate of 2.6 (95% range 0.49–4.7). A 5-year backtest shows a typical error of ±88.2%, 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 →
20262.50.464.6
20272.60.474.6
20282.60.484.7
20292.60.494.7
20302.60.494.7

Routes In Sierra Madre Occidental

Routes recording Warbling Vireo in Sierra Madre Occidental.
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 →
Mt. GrahamARIZONA262025
AlpineARIZONA172025
Aztec PeakARIZONA71978
PrescottARIZONA62025
SprucedaleARIZONA52021
BlueARIZONA31991
Skull ValleyARIZONA32024
PortalARIZONA32025
ReserveNEW-MEXICO32023
Emory PassNEW-MEXICO32025
PatagoniaARIZONA22010
MaineARIZONA21997
Carr MtnARIZONA22025
DragoonARIZONA22009
Vicks PeakNEW-MEXICO22025
FlagstaffARIZONA12025
Mormon LakeARIZONA11974
PomereneARIZONA12022
San SimonARIZONA11979
SunizonaARIZONA11974
Tonto Vill.ARIZONA12015
Forest LakesARIZONA12024
PinetopARIZONA12022
RedingtonARIZONA12021
Happy JackARIZONA12024

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