BirdAnalyst
Species · BCR 10 · BBS 2025 Release · 1966–2024

Fox Sparrow In Northern Rockies

All regionsNorthern RockiesGeneralists

Fox Sparrow in Northern Rockies has increased: up 43% on the route-weighted index since 1970.

+43%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 →
91Routes 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 →
55YearsYears 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 Northern Rockies. See the full index history below.

Fox Sparrow In Northern Rockies Population Forecast

If the recent trend holds, Fox Sparrow in Northern Rockies is projected to fall about 14% by 2029 — from 0.92 in 2024 to a central estimate of 0.79 (95% range 0.33–1.3). A 5-year backtest shows a typical error of ±16.8%, with 100% of held-out values landing inside the 95% band.

-14%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 →
0.79Projected 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 →
0.33–1.395% 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 →
±16.8%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, Fox Sparrow in Northern Rockies is projected to fall about 14% by 2029 — from 0.92 in 2024 to a central estimate of 0.79 (95% range 0.33–1.3). A 5-year backtest shows a typical error of ±16.8%, with 100% 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 →
20250.770.311.2
20260.770.311.2
20270.780.321.2
20280.790.331.2
20290.790.331.3

Routes In Northern Rockies

Routes recording Fox Sparrow in Northern Rockies.
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 →
Buckskin MtnWYOMING212021
Logan PassMONTANA202024
Whitefish LakeMONTANA172024
AveryIDAHO112023
Big SandyWYOMING112024
Lolo PassIDAHO92019
ChallisIDAHO82024
CentervilleIDAHO82019
WoodruffUTAH82024
AlpineWYOMING82024
PierceIDAHO72007
WilsonWYOMING62024
Spring LakeWASHINGTON52024
Colter BayWYOMING51999
Colter Bay 2WYOMING52024
Fish CreekMONTANA42024
Hebgen LakeMONTANA42024
Inside RoadMONTANA42024
CloverlandWASHINGTON42024
OttoWYOMING41987
Great DivideCOLORADO31977
Baldy MountainIDAHO32016
ChestnutMONTANA32009
OchocoOREGON32021
NorthportWASHINGTON31997

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