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

Bobolink Population Trend in Montana

All statesGrassland birds

Bobolink in Montana has surged: up 926% on the route-weighted index since 1970.

+926%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 →
74Routes 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 →
56YearsYears 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 926% 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 26% by 2029 — from 4.1 in 2024 to a central estimate of 3.0 (95% range 1.4–4.6). A 5-year backtest shows a typical error of ±40.6%, with 60% of held-out values landing inside the 95% band.

-26%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 →
3.0Projected 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 →
1.4–4.695% 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 →
±40.6%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 26% by 2029 — from 4.1 in 2024 to a central estimate of 3.0 (95% range 1.4–4.6). A 5-year backtest shows a typical error of ±40.6%, with 60% 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 →
20252.91.34.5
20262.91.34.5
20272.91.34.5
20283.01.44.6
20293.01.44.6

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 →
Raynesford4520242016
Lambert4320242021
Two Dot3520241976
Westby2820242015
Redstone2420241975
Oswego1620241978
Brusett1520241982
Ester Lake1320242015
Lindsay1220242015
Glasgow1020242002
Chuffey Spring1020232023
Sula920241986
Albion920231982
Saco820242015
Coleman Coulee820212017
Hehn Draw820242016
Harlem720211980
Shawmut720241985
Winifred 2720242024
Forsyth720231992
Webster720241978
Chinook720242015
Wolf Creek720192015
Augusta620241976
Circle620231969

Bobolink Population Trend in Other States

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

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