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

Gray Partridge In Eastern Tallgrass Prairie

All regionsEastern Tallgrass PrairieGeneralists

Gray Partridge in Eastern Tallgrass Prairie has collapsed: down 92% on the route-weighted index since 1969.

-92%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 →
33Routes 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 →
50YearsYears 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 →

Gray Partridge has collapsed in Eastern Tallgrass Prairie: down 92% on the route-weighted index since 1969.

Gray Partridge In Eastern Tallgrass Prairie Population Forecast

If the recent trend holds, Gray Partridge in Eastern Tallgrass Prairie is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.17). A 5-year backtest shows a typical error of ±105.7%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.00–0.1795% 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 →
±105.7%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, Gray Partridge in Eastern Tallgrass Prairie is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.17). A 5-year backtest shows a typical error of ±105.7%, 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 →
20250.000.000.17
20260.000.000.17
20270.000.000.17
20280.000.000.17
20290.000.000.17

Routes In Eastern Tallgrass Prairie

Routes recording Gray Partridge 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 →
BedfordIOWA91989
BryantIOWA61998
Mill CreekILLINOIS41988
Cedar ValleyIOWA41991
GazaIOWA32015
AustinMINNESOTA32021
HolcombILLINOIS21993
AtkinsonILLINOIS21987
GeneseoILLINOIS21990
Troy GroveILLINOIS21995
SenecaILLINOIS21999
HebronINDIANA21970
MiddletownINDIANA21972
MilroyINDIANA21970
AliceIOWA21997
PrairieburgIOWA21993
PiersonIOWA22018
Davis CornerIOWA22024
Rock ValleyIOWA22001
Ash CreekMINNESOTA22014
LakevilleMINNESOTA21994
Le RoyMINNESOTA22017
ThurstonNEBRASKA21991
RaymondWISCONSIN21969
SheffieldILLINOIS11991

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