BirdAnalyst
Species · BBS 2026 Release · 1966–2025

Cassin's Finch Population Analysis

FringillidaeForest birdsHaemorhous cassinii

Cassin's Finch has surged: up 132% on the route-weighted index since 1970.

+132%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 →
500RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
57Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

About the Cassin's Finch

The Cassin's Finch (Haemorhous cassinii) is a North American member of the Finches (Fringillidae). In this analysis it is grouped with the forest birds.

Size
4.5–6.5 in long (11–16 cm) — a small songbird (typical for the family)
Habitat
Woodlands and forest edges, including wooded suburbs and parks.
Diet
Insects and spiders gleaned from foliage and bark, with seeds and berries in season.
Range
Recorded on 500 Breeding Bird Survey routes across 12 states, most concentrated in the Northern Rockies.
Family
Fringillidae · Forest birds

Notable Cassin's Finch TrendsNotable 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 surveyed states: up 132% on the route-weighted index since 1970.

Cassin's Finch Population Forecast

If the recent trend holds, Cassin's Finch is projected to stay roughly flat through 2030, near 0.38 (95% range 0.16–0.59). A 5-year backtest shows a typical error of ±33.2%, with 100% of held-out values landing inside the 95% band.

+9%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 →
0.38Projected 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 →
0.16–0.5995% 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 →
±33.2%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 is projected to stay roughly flat through 2030, near 0.38 (95% range 0.16–0.59). A 5-year backtest shows a typical error of ±33.2%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20260.370.150.59
20270.370.150.59
20280.370.150.59
20290.370.150.59
20300.380.160.59

Where the Cassin's Finch Is Detected

BBS routes recording Cassin's Finch, sized by most recent count.

Cassin's Finch Population Trend by State

Cassin's Finch population trend by state.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Arizona-83%19927
California-50%197086
Colorado+488%197181
Idaho+528%197244
Montana+37%197043
Nevada-84%198417
New Mexico-76%19847
Oregon+40%197071
South Dakota-33%19969
Utah+150%197052
Washington-35%197042
Wyoming+69%197441

Cassin's Finch Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Cassin's Finch population trend by Bird Conservation Region.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Northern Pacific Rainforest-75%197027
Great Basin-2%1970117
Northern Rockies-15%1970145
Sierra Nevada+52%197033
Southern Rockies / Colorado Plateau+444%1970137
Badlands and Prairies-78%198117
Coastal California-87%197118

Cassin's Finch Conservation Status

Our route-weighted index shows it up about 132% since 1970.

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14. Trend is a route-weighted relative-abundance index, not an absolute population.