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

Vesper Sparrow Population Trend in New Hampshire

All statesGrassland birds

Vesper Sparrow in New Hampshire has collapsed: down 86% on the route-weighted index since 1968.

-86%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 →
20Routes 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 →
18YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Vesper Sparrow 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 →

Vesper Sparrow has collapsed in New Hampshire: down 86% on the route-weighted index since 1968.

Vesper Sparrow Population Forecast in New Hampshire

If the recent trend holds, Vesper Sparrow in New Hampshire is projected to stay roughly flat through 1999, near 0.00 (95% range 0.00–0.27). A 5-year backtest shows a typical error of ±408.1%, with 100% of held-out values landing inside the 95% band.

n/aChange by 1999TrendPercent 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 1999 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.2795% 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 →
±408.1%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, Vesper Sparrow in New Hampshire is projected to stay roughly flat through 1999, near 0.00 (95% range 0.00–0.27). A 5-year backtest shows a typical error of ±408.1%, with 100% of held-out values landing inside the 95% band.19661999
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 →
19950.000.000.27
19960.000.000.27
19970.000.000.27
19980.000.000.27
19990.000.000.27

Vesper Sparrow Survey Routes in New Hampshire

Routes recording Vesper Sparrow 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 →
Peterborough319711971
Hopkinton219711968
Wilmot219681966
Walpole219701967
Marlow219671967
Dixvil Notch219701966
Brentwood119751967
Fitzwilliam119731969
Dover119751970
Epsom119861986
Concord119761968
Canterbury119751969
Gilmantn I W119711971
Lempster119841984
Crawford Not119691969
Jefferson Hl119681968
Franconia119801967
Milan119941992
Stratford119791966
Clarksville119851985

Vesper Sparrow Population Trend in Other States

arizonacaliforniacoloradoconnecticutdelawareidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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