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

Olive Warbler In Sierra Madre Occidental

All regionsSierra Madre OccidentalForest birds

Olive Warbler in Sierra Madre Occidental has surged: up 360% on the route-weighted index since 1979.

+360%Since 1979TrendPercent 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 →
16Routes 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 →
43YearsYears 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 →

Olive Warbler has surged in Sierra Madre Occidental: up 360% on the route-weighted index since 1979.

Olive Warbler In Sierra Madre Occidental Population Forecast

If the recent trend holds, Olive Warbler in Sierra Madre Occidental is projected to fall about 16% by 2030 — from 1.1 in 2025 to a central estimate of 0.96 (95% range 0.44–1.5). A 5-year backtest shows a typical error of ±72.7%, with 80% of held-out values landing inside the 95% band.

-16%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 →
0.96Projected 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 →
0.44–1.595% 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 →
±72.7%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, Olive Warbler in Sierra Madre Occidental is projected to fall about 16% by 2030 — from 1.1 in 2025 to a central estimate of 0.96 (95% range 0.44–1.5). A 5-year backtest shows a typical error of ±72.7%, with 80% of held-out values landing inside the 95% band.19772030
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 →
20260.900.381.4
20270.920.401.4
20280.930.411.4
20290.950.431.5
20300.960.441.5

Routes In Sierra Madre Occidental

Routes recording Olive Warbler 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. GrahamARIZONA132025
Tonto Vill.ARIZONA72025
PortalARIZONA42025
PrescottARIZONA32018
Forest LakesARIZONA32021
WilliamsARIZONA22001
PinetopARIZONA22022
AlpineARIZONA22025
Carr MtnARIZONA22018
SprucedaleARIZONA22025
Vicks PeakNEW-MEXICO22004
Aztec PeakARIZONA11977
Happy JackARIZONA12025
RuckerARIZONA12004
ReserveNEW-MEXICO12025
Emory PassNEW-MEXICO12025

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