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

Bobolink In Eastern Tallgrass Prairie

All regionsEastern Tallgrass PrairieGrassland birds

Bobolink in Eastern Tallgrass Prairie has collapsed: down 85% on the route-weighted index since 1968.

-85%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 →
196Routes 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 →
59YearsYears 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 →

Bobolink has collapsed in Eastern Tallgrass Prairie: down 85% on the route-weighted index since 1968.

Bobolink In Eastern Tallgrass Prairie Population Forecast

If the recent trend holds, Bobolink in Eastern Tallgrass Prairie is projected to fall about 100% by 2030 — from 1.8 in 2025 to a central estimate of 0.00 (95% range 0.00–2.1). A 5-year backtest shows a typical error of ±98.9%, with 100% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–2.195% 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 →
±98.9%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, Bobolink in Eastern Tallgrass Prairie is projected to fall about 100% by 2030 — from 1.8 in 2025 to a central estimate of 0.00 (95% range 0.00–2.1). A 5-year backtest shows a typical error of ±98.9%, with 100% of held-out values landing inside the 95% band.19662030
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 →
20260.040.002.1
20270.000.002.1
20280.000.002.1
20290.000.002.1
20300.000.002.1

Routes In Eastern Tallgrass Prairie

Routes recording Bobolink 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 →
New HamptonMISSOURI1192025
LucerneMISSOURI842025
GreenviewILLINOIS292005
Concord WestILLINOIS122007
WashtaIOWA122014
NewportOHIO121994
Ash CreekMINNESOTA112025
LacledeMISSOURI92025
McfallMISSOURI92025
XeniaOHIO92016
Le RoyMINNESOTA82025
TrentonMISSOURI82025
MurdockNEBRASKA82025
MonicaILLINOIS72017
ExlineIOWA72025
Davis CornerIOWA72025
FriendswoodINDIANA62000
BedfordIOWA62025
Red RockIOWA62025
HudsonIOWA62022
FrazierMISSOURI62017
Kahoka2MISSOURI62022
KunkleOHIO62025
MarionOHIO61983
River FallsWISCONSIN62025

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