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

Cassin's Finch Population Trend in Colorado

All statesGeneralists

Cassin's Finch in Colorado has surged: up 514% on the route-weighted index since 1971.

+514%Since 1971TrendPercent 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 →
80Routes 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 →
54YearsYears 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 ColoradoNotable 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 surged in Colorado: up 514% on the route-weighted index since 1971.

Cassin's Finch Population Forecast in Colorado

If the recent trend holds, Cassin's Finch in Colorado is projected to rise about 48% by 2029 — from 0.62 in 2024 to a central estimate of 0.92 (95% range 0.07–1.8). A 5-year backtest shows a typical error of ±50.9%, with 100% of held-out values landing inside the 95% band.

+48%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 →
0.92Projected 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 →
0.07–1.895% 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 →
±50.9%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, Cassin's Finch in Colorado is projected to rise about 48% by 2029 — from 0.62 in 2024 to a central estimate of 0.92 (95% range 0.07–1.8). A 5-year backtest shows a typical error of ±50.9%, with 100% of held-out values landing inside the 95% band.19692029
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 →
20250.880.041.7
20260.890.051.7
20270.900.061.7
20280.910.061.7
20290.920.071.8

Cassin's Finch Survey Routes in Colorado

Routes recording Cassin's Finch in Colorado.
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 →
Deadman Rd.1620241992
Buffalo Park1420231992
Cortez 2820142014
Pinos Creek619901988
Blackhead Pk620211995
Powderhorn620231996
Parlin520181970
Castleton520241988
Colona 2520182016
Summitville520121991
Owl Creek Pass520241998
Uncompahgre420241988
Mcphee Res.420242001
Radium420132011
Nucla420242000
Mesaverde Np420061996
Trail Ridge Road420132003
Guffey320241992
Dinosaur320111996
Baxter Pass320241994
Black Sulphur Cr320212015
Yampa220171970
Delta220211974
Pagosa Spgs219821973
Wilson Creek220081993

Cassin's Finch Population Trend in Other States

arizonacaliforniaidahomontananevadanew-mexicooregonsouth-dakotautahwashingtonwyoming

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