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

Purple Finch Population Trend in Connecticut

All statesGeneralists

Purple Finch in Connecticut has collapsed: down 91% on the route-weighted index since 1968.

-91%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 →
19Routes 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 →
53YearsYears 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 ConnecticutNotable 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 collapsed in Connecticut: down 91% on the route-weighted index since 1968.

Purple Finch Population Forecast in Connecticut

If the recent trend holds, Purple Finch in Connecticut is projected to fall about 63% by 2027 — from 0.18 in 2022 to a central estimate of 0.07 (95% range 0.00–0.94). A 5-year backtest shows a typical error of ±219.5%, with 100% of held-out values landing inside the 95% band.

-63%Change by 2027TrendPercent 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 2027 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.9495% 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 →
±219.5%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 Connecticut is projected to fall about 63% by 2027 — from 0.18 in 2022 to a central estimate of 0.07 (95% range 0.00–0.94). A 5-year backtest shows a typical error of ±219.5%, with 100% of held-out values landing inside the 95% band.19662027
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 →
20230.160.001.0
20240.140.001.0
20250.120.000.99
20260.090.000.97
20270.070.000.94

Purple Finch Survey Routes in Connecticut

Routes recording Purple Finch in Connecticut.
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 →
Woodstock419871968
Warren420111972
New Hartford320082000
Westbrook219921970
Sherman220081972
Mid Haddam219951979
Southington219841975
New Hartford219861976
Mystic120021974
E Hartland119911966
Buckingham119791966
Uncasville120081981
Willimantic120051967
No Woodbury120221967
Greenwich119761975
Danbury119751971
Long Hill119831974
Warren 2120152013
Granby120221989

Purple Finch Population Trend in Other States

alaskacaliforniaindianamainemarylandmassachusettsmichiganminnesotanew-hampshirenew-jerseynew-yorknorth-dakotaohiooregonpennsylvaniarhode-islandvermontwashingtonwest-virginiawisconsin

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