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Species · Montana · BBS 2026 Release · 1966–2025

Bobolink Population Trend in Montana

All statesGrassland birds

Bobolink in Montana has surged: up 932% on the route-weighted index since 1970.

+932%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 →
76Routes 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 Bobolink 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 →

Bobolink has surged in Montana: up 932% on the route-weighted index since 1970.

Bobolink Population Forecast in Montana

If the recent trend holds, Bobolink in Montana is projected to fall about 14% by 2030 — from 3.6 in 2025 to a central estimate of 3.1 (95% range 1.5–4.7). A 5-year backtest shows a typical error of ±40.5%, with 60% of held-out values landing inside the 95% band.

-14%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 →
3.1Projected 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 →
1.5–4.795% 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 →
±40.5%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 Montana is projected to fall about 14% by 2030 — from 3.6 in 2025 to a central estimate of 3.1 (95% range 1.5–4.7). A 5-year backtest shows a typical error of ±40.5%, 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 →
20263.01.44.6
20273.01.44.6
20283.01.44.6
20293.11.54.7
20303.11.54.7

Bobolink Survey Routes in Montana

Routes recording Bobolink 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 →
Raynesford6920252016
Lambert5420252021
Redstone2720251975
Webster2120251978
Westby2020252015
Brusett1520241982
Oswego1420251978
Lindsay1220242015
Victor1120251993
Two Dot1120251976
Hehn Draw1120252016
Glasgow1020242002
Coleman Coulee1020242017
Chuffey Spring1020232023
Shawmut920251985
Sula920241986
Albion920231982
Harlem720211980
Forsyth720231992
Wolf Creek720192015
Circle620231969
Chinook620252015
Philipsburg520252015
Augusta420251976
Willow Creek419811972

Bobolink Population Trend in Other States

californiacoloradoconnecticutidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamissourinebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooregonpennsylvaniarhode-islandsouth-dakotautahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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