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

Bewick's Wren In Sierra Madre Occidental

All regionsSierra Madre OccidentalForest birds

Bewick's Wren in Sierra Madre Occidental has fallen sharply: down 57% on the route-weighted index since 1970.

-57%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 →
37Routes 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 →

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 →

Bewick's Wren has fallen sharply in Sierra Madre Occidental: down 57% on the route-weighted index since 1970.

Bewick's Wren In Sierra Madre Occidental Population Forecast

If the recent trend holds, Bewick's Wren in Sierra Madre Occidental is projected to rise about 35% by 2030 — from 5.1 in 2025 to a central estimate of 6.8 (95% range 0.00–20). A 5-year backtest shows a typical error of ±141.7%, with 100% of held-out values landing inside the 95% band.

+35%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 →
6.8Projected 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 →
0.00–2095% 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 →
±141.7%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, Bewick's Wren in Sierra Madre Occidental is projected to rise about 35% by 2030 — from 5.1 in 2025 to a central estimate of 6.8 (95% range 0.00–20). A 5-year backtest shows a typical error of ±141.7%, 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 →
20267.70.0021
20277.50.0021
20287.30.0021
20297.00.0020
20306.80.0020

Routes In Sierra Madre Occidental

Routes recording Bewick's Wren 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 →
DragoonARIZONA292009
PatagoniaARIZONA232025
Peña BlancaARIZONA192025
PortalARIZONA182025
RuckerARIZONA182009
SprucedaleARIZONA132025
PomereneARIZONA112025
Tonto Vill.ARIZONA112025
Forest LakesARIZONA82025
Aztec PeakARIZONA71978
Mormon LakeARIZONA61974
CutterARIZONA62014
PrescottARIZONA52025
SunizonaARIZONA51992
Skull Valley 2ARIZONA52025
Sunizona 2ARIZONA52024
Emory PassNEW-MEXICO52025
Skull ValleyARIZONA32024
RedingtonARIZONA32025
ReserveNEW-MEXICO32019
Vicks PeakNEW-MEXICO32025
MagdalenaNEW-MEXICO32025
BlueARIZONA21990
WilliamsARIZONA22025
Bartlett ResARIZONA22025

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