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

White-throated Sparrow Population Trend in New Hampshire

All statesGeneralists

White-throated Sparrow in New Hampshire has collapsed: down 79% on the route-weighted index since 1968.

-79%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 →
25Routes 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 White-throated 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 →

White-throated Sparrow has collapsed in New Hampshire: down 79% on the route-weighted index since 1968.

White-throated Sparrow Population Forecast in New Hampshire

If the recent trend holds, White-throated Sparrow in New Hampshire is projected to fall about 68% by 2029 — from 3.9 in 2024 to a central estimate of 1.2 (95% range 0.00–4.7). A 5-year backtest shows a typical error of ±25.6%, with 100% of held-out values landing inside the 95% band.

-68%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 →
1.2Projected 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 →
0.00–4.795% 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 →
±25.6%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, White-throated Sparrow in New Hampshire is projected to fall about 68% by 2029 — from 3.9 in 2024 to a central estimate of 1.2 (95% range 0.00–4.7). A 5-year backtest shows a typical error of ±25.6%, 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 →
20252.30.005.7
20262.10.005.5
20271.80.005.2
20281.50.004.9
20291.20.004.7

White-throated Sparrow Survey Routes in New Hampshire

Routes recording White-throated 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 →
Clarksville3420241966
Dixville Notch 23320242018
Dixvil Notch1920171966
Crawford Not1619751966
Franconia520241966
Milan420241966
Gilmantn I W220161969
Mt Chocorua220221966
Jefferson Hl220241966
Stratford220241966
Glen220241975
Jeffers Ntch220241993
Peterborough120171966
Brentwood119921966
Fitzwilliam120091966
Dover120061966
Hopkinton120101966
Epsom120161966
Concord120181966
Strafford120041966
Canterbury120181966
Wilmot120241966
Walpole120231966
Marlow120241966
Lempster120191966

White-throated Sparrow Population Trend in Other States

connecticutmainemassachusettsmichiganminnesotanew-jerseynew-yorknorth-dakotapennsylvaniavermontwest-virginiawisconsin

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