BirdAnalyst
Species · BCR 2 · BBS 2025 Release · 1966–2024

American Tree Sparrow In BCR 2

All regionsBCR 2Generalists

American Tree Sparrow in BCR 2 has increased: up 49% on the route-weighted index since 1987.

+49%Since 1987TrendPercent 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 →
19Routes 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 →
34YearsYears 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 American Tree Sparrow in BCR 2. See the full index history below.

American Tree Sparrow In BCR 2 Population Forecast

If the recent trend holds, American Tree Sparrow in BCR 2 is projected to rise about 471% by 2029 — from 1.3 in 2024 to a central estimate of 7.6 (95% range 0.00–21). A 5-year backtest shows a typical error of ±177.8%, with 100% of held-out values landing inside the 95% band.

+471%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 →
7.6Projected 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 →
0.00–2195% 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 →
±177.8%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, American Tree Sparrow in BCR 2 is projected to rise about 471% by 2029 — from 1.3 in 2024 to a central estimate of 7.6 (95% range 0.00–21). A 5-year backtest shows a typical error of ±177.8%, with 100% of held-out values landing inside the 95% band.19842029
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 →
20258.50.0022
20268.30.0022
20278.10.0021
20287.80.0021
20297.60.0021

Routes In BCR 2

Routes recording American Tree Sparrow in BCR 2.
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 →
Gweek RiverALASKA372002
NomeALASKA362023
Togiak RiverALASKA292005
Kanektok RivALASKA242005
St. Mary'SALASKA152014
Goodnews BayALASKA132005
DillinghamALASKA112012
Salmon LakeALASKA102019
Kugarak (Short)ALASKA91987
TupuknukALASKA81995
King SalmonALASKA62024
Selawik (Short)ALASKA51987
Katmai N.P.ALASKA42022
KotzebueALASKA32024
TellerALASKA22024
Dillingham (Short)ALASKA21984
Cape NomeALASKA12023
CouncilALASKA12024
Kotzebue (Short)ALASKA11994

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