BirdAnalyst
Species · Montana · BBS 2025 Release · 1966–2024

Great Horned Owl Population Trend in Montana

All statesGeneralists

Great Horned Owl in Montana has edged down: down 20% on the route-weighted index since 1970.

-20%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 →
72Routes 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 →
54YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Great Horned Owl 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 →

No notable trend signals for Great Horned Owl in Montana. See the full index history below.

Great Horned Owl Population Forecast in Montana

If the recent trend holds, Great Horned Owl in Montana is projected to rise about 55% by 2029 — from 0.08 in 2024 to a central estimate of 0.13 (95% range 0.00–0.32). A 5-year backtest shows a typical error of ±50.4%, with 100% of held-out values landing inside the 95% band.

+55%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 →
0.13Projected 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 →
0.00–0.3295% 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 →
±50.4%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, Great Horned Owl in Montana is projected to rise about 55% by 2029 — from 0.08 in 2024 to a central estimate of 0.13 (95% range 0.00–0.32). A 5-year backtest shows a typical error of ±50.4%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20250.130.000.32
20260.130.000.32
20270.130.000.32
20280.130.000.32
20290.130.000.32

Great Horned Owl Survey Routes in Montana

Routes recording Great Horned Owl 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 →
Laurel320111971
Clyde Park320182018
St Mary219921968
Cleveland220171980
Elliston220061976
Locate220161981
Saco220212019
Westby220232021
Cramer Creek220061996
Libby Dam119961996
Kalispell120181975
Hay Lake120222018
Sunburst120071986
Virgelle120191991
Harlem120072005
Malta120061998
Glasgow120041990
Glen120192019
Redstone120211992
Willow Creek 2120242024
Polson120221995
Arlee119931993
Augusta119941978
Great Falls119951992
Highwood120231968

Great Horned Owl Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourinebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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