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

Bank Swallow Population Trend in New Hampshire

All statesAerial insectivores

Bank Swallow in New Hampshire has collapsed: down 97% on the route-weighted index since 1968.

-97%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 →
24Routes 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 Bank Swallow 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 →

Bank Swallow has collapsed in New Hampshire: down 97% on the route-weighted index since 1968.

Bank Swallow Population Forecast in New Hampshire

If the recent trend holds, Bank Swallow in New Hampshire is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–2.1). A 5-year backtest shows a typical error of ±346.4%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.00Projected 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 →
0.00–2.195% 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 →
±346.4%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, Bank Swallow in New Hampshire is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–2.1). A 5-year backtest shows a typical error of ±346.4%, 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 →
20250.000.002.1
20260.000.002.1
20270.000.002.1
20280.000.002.1
20290.000.002.1

Bank Swallow Survey Routes in New Hampshire

Routes recording Bank Swallow 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 →
Glen420071975
Fitzwilliam320221966
Clarksville319941969
Dover220081966
Epsom220021977
Gilmantn I W220011970
Wilmot219821966
Mt Chocorua220231967
Walpole219921972
Lempster219901972
Jefferson Hl219951966
Milan220191966
Stratford220101966
Dixvil Notch219991966
Dixville Notch 2220232019
Peterborough119831971
Brentwood119921966
Hopkinton120061966
Concord120241966
Strafford119891966
Canterbury120021983
Marlow120211970
Crawford Not119721971
Franconia120181966

Bank Swallow Population Trend in Other States

alabamaalaskaarkansascaliforniacoloradoconnecticutdelawareidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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