BirdAnalyst
Species · New Hampshire · BBS 2026 Release · 1966–2025

Purple Finch Population Trend in New Hampshire

All statesForest birds

Purple Finch in New Hampshire has fallen sharply: down 61% on the route-weighted index since 1968.

-61%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 →
59YearsYears 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 60% 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 50% by 2030 — from 1.7 in 2025 to a central estimate of 0.86 (95% range 0.00–2.0). A 5-year backtest shows a typical error of ±44.2%, with 80% of held-out values landing inside the 95% band.

-50%Change by 2030TrendPercent 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 →
0.86Projected 2030 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 →
±44.2%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 50% by 2030 — from 1.7 in 2025 to a central estimate of 0.86 (95% range 0.00–2.0). A 5-year backtest shows a typical error of ±44.2%, with 80% of held-out values landing inside the 95% band.19662030
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 →
20261.10.002.2
20271.00.002.1
20280.960.002.1
20290.910.002.0
20300.860.002.0

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 →
Epsom620241966
Strafford520251966
Canterbury520241966
Walpole520251966
Marlow520251966
Lempster420251966
Hopkinton320241968
Wilmot320231966
Crawford Not319751966
Peterborough220241966
Fitzwilliam220251966
Mt Chocorua220251966
Milan220251966
Stratford220251966
Dixvil Notch220171966
Clarksville220251966
Glen220251975
Jeffers Ntch220251994
Brentwood119951966
Dover120251966
Concord120251967
Gilmantn I W120251969
Jefferson Hl120251966
Franconia120251966
East Kingston120172000

Purple Finch Population Trend in Other States

alaskacaliforniaconnecticutindianamainemarylandmassachusettsmichiganminnesotanew-jerseynew-yorknorth-dakotaohiooregonpennsylvaniarhode-islandvermontwashingtonwest-virginiawisconsin

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.