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

Purple Finch Population Trend in Vermont

All statesGeneralists

Purple Finch in Vermont has fallen sharply: down 68% on the route-weighted index since 1968.

-68%Since 1968TrendPercent 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 →
26Routes 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 →
58YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Purple Finch Trends in VermontNotable 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 declinecomputed 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 →

Purple Finch has fallen sharply in Vermont: down 68% on the route-weighted index since 1968.

Purple Finch Population Forecast in Vermont

If the recent trend holds, Purple Finch in Vermont is projected to fall about 60% by 2029 — from 0.94 in 2024 to a central estimate of 0.38 (95% range 0.00–1.7). A 5-year backtest shows a typical error of ±60.6%, with 100% of held-out values landing inside the 95% band.

-60%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 →
0.38Projected 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 →
0.00–1.795% 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 →
±60.6%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, Purple Finch in Vermont is projected to fall about 60% by 2029 — from 0.94 in 2024 to a central estimate of 0.38 (95% range 0.00–1.7). A 5-year backtest shows a typical error of ±60.6%, with 100% of held-out values landing inside the 95% band.19662029
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 →
20250.590.001.9
20260.540.001.8
20270.490.001.8
20280.430.001.7
20290.380.001.7

Purple Finch Survey Routes in Vermont

Routes recording Purple Finch in Vermont.
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 →
Waterville619801968
Hardwick420161966
Newbury 2420232005
North Pownal319931966
S Reading320241966
St Johnsbury320211970
East Calais320241966
Hinesburg319881966
Marlboro220241967
Stratton220241966
S Wallingfrd220141971
East Haven220241966
Middlesex220241969
Newbury220041986
Landgrove120241966
Gaysville120121966
Post Mills120051967
Shaftsbury120241967
W Rutland120231968
Northfld Fls120131980
Greensboro120221967
Fletcher120211969
Colchester120001986
Grand Isle120001972
Stowe120241988

Purple Finch Population Trend in Other States

alaskacaliforniaconnecticutindianamainemarylandmassachusettsmichiganminnesotanew-hampshirenew-jerseynew-yorknorth-dakotaohiooregonpennsylvaniarhode-islandwashingtonwest-virginiawisconsin

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