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

MacGillivray's Warbler In Sierra Madre Occidental

All regionsSierra Madre OccidentalForest birds

MacGillivray's Warbler in Sierra Madre Occidental has increased: up 26% on the route-weighted index since 1998.

+26%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 →
4Routes 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 →
18YearsYears 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 MacGillivray's Warbler in Sierra Madre Occidental. See the full index history below.

MacGillivray's Warbler In Sierra Madre Occidental Population Forecast

If the recent trend holds, MacGillivray's Warbler in Sierra Madre Occidental is projected to rise about 89% by 2030 — from 0.07 in 2025 to a central estimate of 0.14 (95% range 0.02–0.26). A 5-year backtest shows a typical error of ±177.2%, with 40% of held-out values landing inside the 95% band.

+89%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 →
0.14Projected 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 →
0.02–0.2695% 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 →
±177.2%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, MacGillivray's Warbler in Sierra Madre Occidental is projected to rise about 89% by 2030 — from 0.07 in 2025 to a central estimate of 0.14 (95% range 0.02–0.26). A 5-year backtest shows a typical error of ±177.2%, with 40% of held-out values landing inside the 95% band.19932030
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 →
20260.130.010.25
20270.130.010.25
20280.140.010.26
20290.140.020.26
20300.140.020.26

Routes In Sierra Madre Occidental

Routes recording MacGillivray's 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 →
AlpineARIZONA22025
ReserveNEW-MEXICO22021
Mt. GrahamARIZONA12022
SprucedaleARIZONA12010

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