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

Savannah Sparrow Population Trend in New Hampshire

All statesGrassland birds

Savannah Sparrow in New Hampshire has fallen sharply: down 59% on the route-weighted index since 1968.

-59%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 →
23Routes 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 Savannah 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 →

Savannah Sparrow has fallen sharply in New Hampshire: down 59% on the route-weighted index since 1968.

Savannah Sparrow Population Forecast in New Hampshire

If the recent trend holds, Savannah Sparrow in New Hampshire is projected to fall about 31% by 2029 — from 1.0 in 2024 to a central estimate of 0.72 (95% range 0.04–1.4). A 5-year backtest shows a typical error of ±31.2%, with 100% of held-out values landing inside the 95% band.

-31%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 →
0.72Projected 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 →
0.04–1.495% 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 →
±31.2%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, Savannah Sparrow in New Hampshire is projected to fall about 31% by 2029 — from 1.0 in 2024 to a central estimate of 0.72 (95% range 0.04–1.4). A 5-year backtest shows a typical error of ±31.2%, with 100% 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 →
20250.770.081.5
20260.760.071.4
20270.750.061.4
20280.740.051.4
20290.720.041.4

Savannah Sparrow Survey Routes in New Hampshire

Routes recording Savannah 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 →
Dixvil Notch1120171966
Dixville Notch 2720242018
Franconia620241966
Stratford320241966
Walpole220221967
Milan220221966
Clarksville220241966
Glen220241975
Peterborough119791970
Brentwood119731967
Fitzwilliam120221966
Dover120041973
Hopkinton120221969
Epsom119671967
Concord120231970
Canterbury120221970
Gilmantn I W120241975
Wilmot120161977
Mt Chocorua120192009
Marlow120241976
Lempster120242017
Jefferson Hl120211967
Jeffers Ntch120072001

Savannah Sparrow Population Trend in Other States

alaskaarizonacaliforniacoloradoconnecticutdelawareidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooregonpennsylvaniarhode-islandsouth-dakotatennesseeutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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