BirdAnalyst
Species · BCR 22 · BBS 2025 Release · 1966–2024

Bobolink In Eastern Tallgrass Prairie

All regionsEastern Tallgrass PrairieGrassland birds

Bobolink in Eastern Tallgrass Prairie has collapsed: down 91% on the route-weighted index since 1968.

-91%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 →
195Routes 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 →

Bobolink has collapsed in Eastern Tallgrass Prairie: down 91% 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 2029 — from 0.57 in 2024 to a central estimate of 0.00 (95% range 0.00–2.0). A 5-year backtest shows a typical error of ±103.9%, with 100% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–2.095% 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 →
±103.9%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 2029 — from 0.57 in 2024 to a central estimate of 0.00 (95% range 0.00–2.0). A 5-year backtest shows a typical error of ±103.9%, with 100% 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 →
20250.000.002.0
20260.000.002.0
20270.000.002.0
20280.000.002.0
20290.000.002.0

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 →
LucerneMISSOURI452021
GreenviewILLINOIS292005
BedfordIOWA172018
Concord WestILLINOIS122007
WashtaIOWA122014
Ash CreekMINNESOTA122024
NewportOHIO121994
McfallMISSOURI102024
SticklervillMISSOURI92024
XeniaOHIO92016
MonicaILLINOIS72017
Davis CornerIOWA72024
FriendswoodINDIANA62000
HudsonIOWA62022
FrazierMISSOURI62017
TrentonMISSOURI62024
Kahoka2MISSOURI62022
KunkleOHIO62023
MarionOHIO61983
WilliamsfldILLINOIS52014
BrooklynIOWA52021
WalesIOWA52018
New HamptonMISSOURI52024
SherburnvillILLINOIS42012
SwayzeeINDIANA42003

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