BirdAnalyst
Species · BCR 12 · BBS 2025 Release · 1966–2024

Field Sparrow In Boreal Hardwood Transition

All regionsBoreal Hardwood TransitionGeneralists

Field Sparrow in Boreal Hardwood Transition has fallen sharply: down 64% on the route-weighted index since 1968.

-64%Since 1968TrendPercent 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 →
83Routes 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 →
58YearsYears 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 declinecomputed 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 →

Field Sparrow has fallen sharply in Boreal Hardwood Transition: down 64% on the route-weighted index since 1968.

Field Sparrow In Boreal Hardwood Transition Population Forecast

If the recent trend holds, Field Sparrow in Boreal Hardwood Transition is projected to fall about 91% by 2029 — from 0.64 in 2024 to a central estimate of 0.06 (95% range 0.00–0.61). A 5-year backtest shows a typical error of ±61.6%, with 80% of held-out values landing inside the 95% band.

-91%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 →
0.06Projected 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 →
0.00–0.6195% 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 →
±61.6%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, Field Sparrow in Boreal Hardwood Transition is projected to fall about 91% by 2029 — from 0.64 in 2024 to a central estimate of 0.06 (95% range 0.00–0.61). A 5-year backtest shows a typical error of ±61.6%, with 80% of held-out values landing inside the 95% band.19662029
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 →
20250.150.000.70
20260.120.000.68
20270.100.000.66
20280.080.000.63
20290.060.000.61

Routes In Boreal Hardwood Transition

Routes recording Field Sparrow in Boreal Hardwood Transition.
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 →
Union TwpWISCONSIN152024
HarriettaMICHIGAN92024
Sand LakeMICHIGAN82024
Hubbard LakeMICHIGAN71988
Bear LakeMICHIGAN62024
Red OakMICHIGAN52022
Gibbs CityMICHIGAN41993
Lake CityMICHIGAN42022
IronsMICHIGAN41989
Brush CreekMICHIGAN32016
SkeelsMICHIGAN32008
FredericMICHIGAN31997
WausaukeeWISCONSIN32024
CathroMICHIGAN22015
Pleasant Valley 2MICHIGAN22024
FloodwoodMINNESOTA21981
BemidjiMINNESOTA21979
DebsMINNESOTA22008
BayfieldWISCONSIN22009
ExelandWISCONSIN22008
McnaughtonWISCONSIN22024
Eagle RiverWISCONSIN21986
OntonagonMICHIGAN12015
MareniscoMICHIGAN12005
Crystal FlsMICHIGAN11992

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