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

Purple Finch Population Trend in Pennsylvania

All statesGeneralists

Purple Finch in Pennsylvania has declined: down 45% on the route-weighted index since 1968.

-45%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 →
86Routes 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 PennsylvaniaNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Purple Finch in Pennsylvania. See the full index history below.

Purple Finch Population Forecast in Pennsylvania

If the recent trend holds, Purple Finch in Pennsylvania is projected to rise about 123% by 2029 — from 0.24 in 2024 to a central estimate of 0.53 (95% range 0.17–0.88). A 5-year backtest shows a typical error of ±90.5%, with 60% of held-out values landing inside the 95% band.

+123%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 →
0.53Projected 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 →
0.17–0.8895% 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 →
±90.5%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 Pennsylvania is projected to rise about 123% by 2029 — from 0.24 in 2024 to a central estimate of 0.53 (95% range 0.17–0.88). A 5-year backtest shows a typical error of ±90.5%, with 60% 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 →
20250.530.170.89
20260.530.170.88
20270.530.170.88
20280.530.170.88
20290.530.170.88

Purple Finch Survey Routes in Pennsylvania

Routes recording Purple Finch in Pennsylvania.
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 →
Roulette1020211974
Marsh Hill420241983
Teepleville320181966
Betula320221975
Rasselas320221969
Mawr Glen320231971
Sugar Grove320241980
Slippery Rk219921970
Akeley219761966
Sigel220241981
N Pine Grove220191975
Eldred220221973
Arnot220231971
Little Marsh220051973
Honesdale220231972
Shelocta220211984
Margaret220241970
Munson220241987
New Ringgold220171966
Big Flat219741974
Harrisville220182011
Duboistown220032003
Pocono Summit 2220072007
Berwick220091990
Espyville120191967

Purple Finch Population Trend in Other States

alaskacaliforniaconnecticutindianamainemarylandmassachusettsmichiganminnesotanew-hampshirenew-jerseynew-yorknorth-dakotaohiooregonrhode-islandvermontwashingtonwest-virginiawisconsin

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