BirdAnalyst
Species · BCR 3 · BBS 2025 Release · 1966–2024

Fox Sparrow In BCR 3

All regionsBCR 3Generalists

Fox Sparrow in BCR 3 has surged: up 145% on the route-weighted index since 1996.

+145%Since 1996TrendPercent 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 →
30YearsYears 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 →

Fox Sparrow has surged in BCR 3: up 145% on the route-weighted index since 1996.

Fox Sparrow In BCR 3 Population Forecast

If the recent trend holds, Fox Sparrow in BCR 3 is projected to stay roughly flat through 2029, near 5.4 (95% range 2.2–8.6). A 5-year backtest shows a typical error of ±44.2%, with 100% of held-out values landing inside the 95% band.

-1%Change by 2029TrendPercent 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 →
5.4Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
2.2–8.695% 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 →
±44.2%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, Fox Sparrow in BCR 3 is projected to stay roughly flat through 2029, near 5.4 (95% range 2.2–8.6). A 5-year backtest shows a typical error of ±44.2%, with 100% of held-out values landing inside the 95% band.19942029
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 →
20254.91.78.1
20265.01.88.2
20275.22.08.4
20285.32.18.5
20295.42.28.6

Routes In BCR 3

Routes recording Fox Sparrow in BCR 3.
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 →
Red DogALASKA142024
Dietrich CmpALASKA42024
Happy ValleyALASKA42024
Galbraith L.ALASKA12012

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.