BirdAnalyst
Species · New Hampshire · BBS 2025 Release · 1966–2024

Purple Finch Population Trend in New Hampshire

All statesGeneralists

Purple Finch in New Hampshire has fallen sharply: down 65% on the route-weighted index since 1968.

-65%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 New HampshireNotable 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 New Hampshire: down 64% on the route-weighted index since 1968.

Purple Finch Population Forecast in New Hampshire

If the recent trend holds, Purple Finch in New Hampshire is projected to fall about 51% by 2029 — from 1.7 in 2024 to a central estimate of 0.85 (95% range 0.00–2.0). A 5-year backtest shows a typical error of ±34.5%, with 80% of held-out values landing inside the 95% band.

-51%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 →
0.85Projected 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 →
0.00–2.095% 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 →
±34.5%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 New Hampshire is projected to fall about 51% by 2029 — from 1.7 in 2024 to a central estimate of 0.85 (95% range 0.00–2.0). A 5-year backtest shows a typical error of ±34.5%, with 80% 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 →
20251.10.002.2
20261.00.002.1
20270.950.002.1
20280.900.002.0
20290.850.002.0

Purple Finch Survey Routes in New Hampshire

Routes recording Purple Finch in New Hampshire.
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 →
Canterbury520241966
Strafford420241966
Marlow420241966
Dover320211966
Hopkinton320241968
Wilmot320231966
Mt Chocorua320241966
Walpole320241966
Lempster320241966
Crawford Not319751966
Jefferson Hl320241966
Peterborough220241966
Concord220241967
Milan220241966
Dixvil Notch220171966
Glen220241975
Brentwood119951966
Fitzwilliam120241966
Epsom120161966
Gilmantn I W120221969
Franconia120231966
Stratford120231966
Clarksville120241966
East Kingston120172000
Jeffers Ntch120231994

Purple Finch Population Trend in Other States

alaskacaliforniaconnecticutindianamainemarylandmassachusettsmichiganminnesotanew-jerseynew-yorknorth-dakotaohiooregonpennsylvaniarhode-islandvermontwashingtonwest-virginiawisconsin

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