BirdAnalyst
Species · BCR 4 · BBS 2025 Release · 1966–2024

Fox Sparrow In BCR 4

All regionsBCR 4Generalists

Fox Sparrow in BCR 4 has declined: down 38% on the route-weighted index since 1976.

-38%Since 1976TrendPercent 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 →
66Routes 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 →
46YearsYears 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 Fox Sparrow in BCR 4. See the full index history below.

Fox Sparrow In BCR 4 Population Forecast

If the recent trend holds, Fox Sparrow in BCR 4 is projected to rise about 45% by 2029 — from 12 in 2024 to a central estimate of 17 (95% range 7.6–26). A 5-year backtest shows a typical error of ±57.6%, with 80% of held-out values landing inside the 95% band.

+45%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 →
17Projected 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 →
7.6–2695% 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 →
±57.6%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 4 is projected to rise about 45% by 2029 — from 12 in 2024 to a central estimate of 17 (95% range 7.6–26). A 5-year backtest shows a typical error of ±57.6%, with 80% of held-out values landing inside the 95% band.19682029
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 →
2025167.125
2026167.226
2027177.426
2028177.526
2029177.626

Routes In BCR 4

Routes recording Fox Sparrow in BCR 4.
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 →
Goose BayALASKA481982
Anvik RiverALASKA462024
KachemakALASKA362024
MonahanALASKA352021
ToklatALASKA342024
CohoeALASKA332023
Anchor RiverALASKA322024
Koyukuk Riv.ALASKA322001
Mt. FairplayALASKA312024
DeltaALASKA282024
Mud RiverALASKA272024
Lake LouiseALASKA252014
TatalinaALASKA232019
Hather CreekALASKA222024
Caribou Mtn.ALASKA212024
Unalakleet RiverALASKA202024
EagleALASKA192024
Kobuk River (Short)ALASKA191992
Chatanika RALASKA172023
SavageALASKA172024
ChickenALASKA152024
HomerALASKA141982
ColdfootALASKA112024
RubyALASKA112024
MatanuskaALASKA101983

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