BirdAnalyst
Species · Montana · BBS 2026 Release · 1966–2025

Gray Partridge Population Trend in Montana

All statesGame birds

Gray Partridge in Montana has surged: up 124% on the route-weighted index since 1970.

+124%Since 1970TrendPercent 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 →
55Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
57YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Gray Partridge Trends in MontanaNotable 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 →

Gray Partridge has surged in Montana: up 124% on the route-weighted index since 1970.

Gray Partridge Population Forecast in Montana

If the recent trend holds, Gray Partridge in Montana is projected to fall about 56% by 2030 — from 0.81 in 2025 to a central estimate of 0.36 (95% range 0.00–0.88). A 5-year backtest shows a typical error of ±41.1%, with 60% of held-out values landing inside the 95% band.

-56%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 →
0.36Projected 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 →
0.00–0.8895% 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 →
±41.1%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 Montana is projected to fall about 56% by 2030 — from 0.81 in 2025 to a central estimate of 0.36 (95% range 0.00–0.88). A 5-year backtest shows a typical error of ±41.1%, with 60% of held-out values landing inside the 95% band.19682030
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 →
20260.360.000.88
20270.360.000.88
20280.360.000.88
20290.360.000.88
20300.360.000.88

Gray Partridge Survey Routes in Montana

Routes recording Gray Partridge in Montana.
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 →
Lambert1720252021
Clyde Park1220242021
Circle820131973
Glentana720242015
Glasgow620251968
Chinook620252016
Leroy520251988
Wolf Point520242015
Virgelle420251979
Redstone420251970
Pablo Res.420251997
Church Hill420252017
Whitlash420222009
Hay Lake320251989
Oswego320231978
Highwood320231970
Shawmut320251984
Flatwillow320071978
Laurel320191973
Shelby320252015
Lindsay320242016
Harlem220171988
Glen220211979
Willow Creek 2220241984
Augusta219891984

Gray Partridge Population Trend in Other States

idahoillinoisindianaiowaminnesotanebraskanevadanew-yorknorth-dakotaoregonsouth-dakotautahwashingtonwisconsinwyoming

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