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

Cassin's Finch Population Trend in Montana

All statesGeneralists

Cassin's Finch in Montana has risen sharply: up 57% on the route-weighted index since 1970.

+57%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 →
43Routes 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 Cassin's Finch 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 →

Cassin's Finch has risen sharply in Montana: up 57% on the route-weighted index since 1970.

Cassin's Finch Population Forecast in Montana

If the recent trend holds, Cassin's Finch in Montana is projected to rise about 23% by 2029 — from 0.36 in 2024 to a central estimate of 0.45 (95% range 0.00–1.3). A 5-year backtest shows a typical error of ±176.8%, with 100% of held-out values landing inside the 95% band.

+23%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 →
0.45Projected 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 →
0.00–1.395% 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 →
±176.8%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, Cassin's Finch in Montana is projected to rise about 23% by 2029 — from 0.36 in 2024 to a central estimate of 0.45 (95% range 0.00–1.3). A 5-year backtest shows a typical error of ±176.8%, 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 →
20250.460.001.3
20260.460.001.3
20270.450.001.3
20280.450.001.3
20290.450.001.3

Cassin's Finch Survey Routes in Montana

Routes recording Cassin's Finch 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 →
Greenoagh 2620112009
Elevation Mt520242003
Greenoagh 3520242015
Sula420241977
Clancy420172015
Hebgen Lake420242017
Libby Dam319941979
Logan Pass319921980
Victor320161993
Arlee320151972
Chestnut320241968
East Glacier Park320182018
Thompson Riv320221993
Fish Creek320241997
Kalispell220221970
Threemile Wa220241993
Greenough220031995
Pryor Mtn.220191995
St Regis220241978
Augusta219991994
Savage219961996
Reed Point220151977
Whitefish Lake220222021
Painted Rock220221992
Noxon220222004

Cassin's Finch Population Trend in Other States

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