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

Common Loon Population Trend in Montana

All statesWetland birds

Common Loon in Montana has held roughly steady: down 9% on the route-weighted index since 1979.

-9%Since 1979TrendPercent 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 →
15Routes 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 →
43YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Common Loon 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 Common Loon in Montana. See the full index history below.

Common Loon Population Forecast in Montana

If the recent trend holds, Common Loon in Montana is projected to fall about 20% by 2029 — from 0.08 in 2024 to a central estimate of 0.07 (95% range 0.00–0.13). A 5-year backtest shows a typical error of ±141.9%, with 100% of held-out values landing inside the 95% band.

-20%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 →
0.07Projected 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 →
0.00–0.1395% 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 →
±141.9%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, Common Loon in Montana is projected to fall about 20% by 2029 — from 0.08 in 2024 to a central estimate of 0.07 (95% range 0.00–0.13). A 5-year backtest shows a typical error of ±141.9%, with 100% of held-out values landing inside the 95% band.19712029
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 →
20250.070.000.13
20260.070.000.13
20270.070.000.13
20280.070.000.13
20290.070.000.13

Common Loon Survey Routes in Montana

Routes recording Common Loon 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 →
Inside Road320241992
East Glacier Park320172017
Logan Pass220131980
Pablo Res.220162016
Two Dot220121979
Libby Dam120152015
Kalispell120132004
St Mary120081974
Noxon120152015
St. Mary 2120242009
Arlee120241971
Great Falls119921992
Hebgen Lake120242024
Painted Rock119991993
Swan Lake120242019

Common Loon Population Trend in Other States

alaskaidahomainemassachusettsmichiganminnesotanew-hampshirenew-yorknorth-dakotaoregonvermontwashingtonwisconsinwyoming

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