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

Purple Finch Population Trend in Maine

All statesGeneralists

Purple Finch in Maine has collapsed: down 84% on the route-weighted index since 1968.

-84%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 →
78Routes 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 MaineNotable 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 Maine: down 84% on the route-weighted index since 1968.

Purple Finch Population Forecast in Maine

If the recent trend holds, Purple Finch in Maine is projected to fall about 100% by 2029 — from 2.0 in 2024 to a central estimate of 0.00 (95% range 0.00–4.7). A 5-year backtest shows a typical error of ±123%, with 100% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–4.795% 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 →
±123%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 Maine is projected to fall about 100% by 2029 — from 2.0 in 2024 to a central estimate of 0.00 (95% range 0.00–4.7). A 5-year backtest shows a typical error of ±123%, 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 →
20250.000.004.7
20260.000.004.7
20270.000.004.7
20280.000.004.7
20290.000.004.7

Purple Finch Survey Routes in Maine

Routes recording Purple Finch in Maine.
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 →
Northfield2319811976
Pillsbury Pd2319681968
Baxter1819841977
Carrying Pl1120241979
Seboomook Lk1020141972
Priestly Br.1020131994
Ludlow819981968
Big Twenty 2820092009
Hancock620241969
Clayton Lake620011977
East Troy520181973
Charleston520171975
Waite519771977
Baker Lake 2520132010
Benton419801972
Washburn420051980
Topsfield419961978
Biddeford320131974
Newcastle320241971
Wilson Mills320241983
Bethel320191977
Warren319901973
Deblois320071966
Moose River320081983
Wytopitlock319981976

Purple Finch Population Trend in Other States

alaskacaliforniaconnecticutindianamarylandmassachusettsmichiganminnesotanew-hampshirenew-jerseynew-yorknorth-dakotaohiooregonpennsylvaniarhode-islandvermontwashingtonwest-virginiawisconsin

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