BirdAnalyst
Species · BCR 22 · BBS 2026 Release · 1966–2025

Eurasian Tree Sparrow In Eastern Tallgrass Prairie

All regionsEastern Tallgrass PrairieGeneralists

Eurasian Tree Sparrow in Eastern Tallgrass Prairie has surged: up 771% on the route-weighted index since 1969.

+771%Since 1969TrendPercent 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 →
63Routes 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 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 →

Eurasian Tree Sparrow has surged in Eastern Tallgrass Prairie: up 771% on the route-weighted index since 1969.

Eurasian Tree Sparrow In Eastern Tallgrass Prairie Population Forecast

If the recent trend holds, Eurasian Tree Sparrow in Eastern Tallgrass Prairie is projected to fall about 17% by 2030 — from 0.91 in 2025 to a central estimate of 0.76 (95% range 0.37–1.1). A 5-year backtest shows a typical error of ±40.8%, with 40% of held-out values landing inside the 95% band.

-17%Change by 2030TrendPercent 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 →
0.76Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.37–1.195% 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 →
±40.8%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, Eurasian Tree Sparrow in Eastern Tallgrass Prairie is projected to fall about 17% by 2030 — from 0.91 in 2025 to a central estimate of 0.76 (95% range 0.37–1.1). A 5-year backtest shows a typical error of ±40.8%, with 40% of held-out values landing inside the 95% band.19672030
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 →
20260.710.321.1
20270.720.341.1
20280.730.351.1
20290.740.361.1
20300.760.371.1

Routes In Eastern Tallgrass Prairie

Routes recording Eurasian Tree Sparrow in Eastern Tallgrass Prairie.
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 →
CameronILLINOIS182025
West LibertyIOWA182024
PaysonILLINOIS162025
ConcordILLINOIS142023
SherrardILLINOIS142025
Camp PointILLINOIS122025
BudaILLINOIS102023
BelleviewILLINOIS102025
EubanksILLINOIS102025
Terre HauteILLINOIS92025
BryantIOWA92025
GreenviewILLINOIS72025
Kahoka2MISSOURI72024
MillwoodMISSOURI62025
Mill CreekILLINOIS52023
PutnamILLINOIS52024
WilliamsfldILLINOIS52025
AtkinsonILLINOIS42024
BartonvilleILLINOIS42025
DudleyvilleILLINOIS42025
WilliamsburgIOWA42023
RensselaerMISSOURI42025
GulfportILLINOIS32025
StillwellILLINOIS32025
Deer CreekILLINOIS32024

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.