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

Bell's Vireo In Sierra Madre Occidental

All regionsSierra Madre OccidentalForest birds

Bell's Vireo in Sierra Madre Occidental has edged down: down 14% on the route-weighted index since 1970.

-14%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 →
20Routes 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 →

No notable trend signals for Bell's Vireo in Sierra Madre Occidental. See the full index history below.

Bell's Vireo In Sierra Madre Occidental Population Forecast

If the recent trend holds, Bell's Vireo in Sierra Madre Occidental is projected to rise about 19% by 2030 — from 5.0 in 2025 to a central estimate of 6.0 (95% range 2.1–9.9). A 5-year backtest shows a typical error of ±29.3%, with 100% of held-out values landing inside the 95% band.

+19%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 →
6.0Projected 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 →
2.1–9.995% 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 →
±29.3%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, Bell's Vireo in Sierra Madre Occidental is projected to rise about 19% by 2030 — from 5.0 in 2025 to a central estimate of 6.0 (95% range 2.1–9.9). A 5-year backtest shows a typical error of ±29.3%, 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 →
20265.92.09.8
20275.92.09.8
20285.92.09.8
20296.02.09.9
20306.02.19.9

Routes In Sierra Madre Occidental

Routes recording Bell's 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 →
PomereneARIZONA662025
RedingtonARIZONA152025
CutterARIZONA132014
AmadoARIZONA132025
Carr MtnARIZONA112025
Peña BlancaARIZONA102025
SunizonaARIZONA81997
Bartlett ResARIZONA72025
PatagoniaARIZONA62025
SahuaritaARIZONA42025
Skull ValleyARIZONA32024
San SimonARIZONA22024
McnealARIZONA22025
Sunizona 2ARIZONA22025
Mormon LakeARIZONA11968
Aztec PeakARIZONA11976
PortalARIZONA12024
DragoonARIZONA12001
RuckerARIZONA11999
Emory PassNEW-MEXICO11998

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