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Species · Montana · BBS 2026 Release · 1966–2025

Marbled Godwit Population Trend in Montana

All statesShorebirds

Marbled Godwit in Montana has surged: up 482% on the route-weighted index since 1975.

+482%Since 1975TrendPercent 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 →
48Routes 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 →
52YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Marbled Godwit 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 →

Marbled Godwit has surged in Montana: up 482% on the route-weighted index since 1975.

Marbled Godwit Population Forecast in Montana

If the recent trend holds, Marbled Godwit in Montana is projected to fall about 13% by 2030 — from 1.6 in 2025 to a central estimate of 1.4 (95% range 0.74–2.0). A 5-year backtest shows a typical error of ±25.5%, with 100% of held-out values landing inside the 95% band.

-13%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 →
1.4Projected 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 →
0.74–2.095% 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 →
±25.5%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, Marbled Godwit in Montana is projected to fall about 13% by 2030 — from 1.6 in 2025 to a central estimate of 1.4 (95% range 0.74–2.0). A 5-year backtest shows a typical error of ±25.5%, with 100% of held-out values landing inside the 95% band.19722030
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 →
20261.30.651.9
20271.30.671.9
20281.30.691.9
20291.30.722.0
20301.40.742.0

Marbled Godwit Survey Routes in Montana

Routes recording Marbled Godwit 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 →
Glasgow1520251982
Ester Lake1420252015
Flatwillow 21320132013
Saco1320252015
Westby1220252015
Virgelle1020251989
Chinook820252015
Oswego720251978
Shelby720252015
Dinosaurs H.M.720252018
Hay Lake520171989
Redstone520251973
Gildford520252015
Glentana520252015
Jordan South520212017
Great Falls420251972
Flatwillow420031976
Wolf Point420242015
Lindsay420242023
Lambert420232022
Roundup420252016
Augusta320211979
Ingomar320251993
Coleman Coulee320242018
Highwood220111990

Marbled Godwit Population Trend in Other States

minnesotanorth-dakotasouth-dakota

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