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

Philadelphia Vireo Population Trend in New Hampshire

All statesForest birds

Philadelphia Vireo in New Hampshire has held roughly steady: down 10% on the route-weighted index since 1969.

-10%Since 1969TrendPercent 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 →
12Routes 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 →
26YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Philadelphia Vireo 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 →

No notable trend signals for Philadelphia Vireo in New Hampshire. See the full index history below.

Philadelphia Vireo Population Forecast in New Hampshire

If the recent trend holds, Philadelphia Vireo in New Hampshire is projected to fall about 20% by 2030 — from 0.09 in 2025 to a central estimate of 0.07 (95% range 0.01–0.13). A 5-year backtest shows a typical error of ±37.3%, with 80% of held-out values landing inside the 95% band.

-20%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 →
0.07Projected 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 →
0.01–0.1395% 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 →
±37.3%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, Philadelphia Vireo in New Hampshire is projected to fall about 20% by 2030 — from 0.09 in 2025 to a central estimate of 0.07 (95% range 0.01–0.13). A 5-year backtest shows a typical error of ±37.3%, with 80% of held-out values landing inside the 95% band.19672030
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 →
20260.070.010.13
20270.070.010.13
20280.070.010.13
20290.070.010.13
20300.070.010.13

Philadelphia Vireo Survey Routes in New Hampshire

Routes recording Philadelphia Vireo 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 →
Jefferson Hl220251969
Peterborough119841984
Concord119891989
Wilmot119841984
Mt Chocorua120242021
Crawford Not119741967
Franconia119811981
Milan120171967
Stratford119791979
Dixvil Notch119761972
Clarksville120232015
Jeffers Ntch120041994

Philadelphia Vireo Population Trend in Other States

alabamamainemichiganminnesotanew-yorknorth-dakotavermontwisconsin

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