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

Blue-headed Vireo Population Trend in New Hampshire

All statesForest birds

Blue-headed Vireo in New Hampshire has surged: up 296% on the route-weighted index since 1968.

+296%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 Blue-headed 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 →

long arc increasecomputed 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 →

Blue-headed Vireo has surged in New Hampshire: up 296% on the route-weighted index since 1968.

Blue-headed Vireo Population Forecast in New Hampshire

If the recent trend holds, Blue-headed Vireo in New Hampshire is projected to stay roughly flat through 2029, near 4.4 (95% range 2.8–6.1). A 5-year backtest shows a typical error of ±17.2%, with 80% of held-out values landing inside the 95% band.

+1%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 →
4.4Projected 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 →
2.8–6.195% 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 →
±17.2%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, Blue-headed Vireo in New Hampshire is projected to stay roughly flat through 2029, near 4.4 (95% range 2.8–6.1). A 5-year backtest shows a typical error of ±17.2%, 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 →
20254.22.65.9
20264.32.65.9
20274.32.76.0
20284.42.76.0
20294.42.86.1

Blue-headed Vireo Survey Routes in New Hampshire

Routes recording Blue-headed 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 →
Mt Chocorua1220241966
Clarksville1220241966
Jefferson Hl1120241966
Marlow1020241967
Dixville Notch 2920242018
Franconia820241966
Jeffers Ntch720241993
Dixvil Notch620171967
Crawford Not519751968
Milan520241966
Glen520241975
Gilmantn I W320241971
Wilmot320231971
Walpole320241967
Fitzwilliam220241966
Strafford220241966
Canterbury220241970
Stratford220241967
Peterborough120241969
Brentwood119931973
Dover120071966
Hopkinton120241968
Epsom120231968
Concord120231967
Lempster120241966

Blue-headed Vireo Population Trend in Other States

alabamaconnecticutgeorgiakentuckymainemarylandmassachusettsmichiganminnesotanew-jerseynew-yorknorth-carolinanorth-dakotaohiopennsylvaniarhode-islandsouth-carolinatennesseevermontvirginiawest-virginiawisconsin

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