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

Song Sparrow In Sierra Madre Occidental

All regionsSierra Madre OccidentalForest birds

Song Sparrow in Sierra Madre Occidental has surged: up 81% on the route-weighted index since 1984.

+81%Since 1984TrendPercent 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 →
10Routes 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 →
41YearsYears 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 →

Song Sparrow has surged in Sierra Madre Occidental: up 81% on the route-weighted index since 1984.

Song Sparrow In Sierra Madre Occidental Population Forecast

If the recent trend holds, Song Sparrow in Sierra Madre Occidental is projected to fall about 57% by 2030 — from 0.44 in 2025 to a central estimate of 0.19 (95% range 0.00–0.45). A 5-year backtest shows a typical error of ±52.8%, with 80% of held-out values landing inside the 95% band.

-57%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 →
0.19Projected 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 →
0.00–0.4595% 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 →
±52.8%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, Song Sparrow in Sierra Madre Occidental is projected to fall about 57% by 2030 — from 0.44 in 2025 to a central estimate of 0.19 (95% range 0.00–0.45). A 5-year backtest shows a typical error of ±52.8%, with 80% of held-out values landing inside the 95% band.19792030
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 →
20260.190.000.45
20270.190.000.45
20280.190.000.45
20290.190.000.45
20300.190.000.45

Routes In Sierra Madre Occidental

Routes recording Song Sparrow 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 →
PatagoniaARIZONA42025
Carr MtnARIZONA42025
CutterARIZONA32014
PomereneARIZONA22025
BlueARIZONA11987
MaineARIZONA12003
Skull ValleyARIZONA12015
Tonto Vill.ARIZONA12025
RedingtonARIZONA12025
SprucedaleARIZONA12007

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