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

Red-winged Blackbird Population Trend in New Hampshire

All statesGeneralists

Red-winged Blackbird in New Hampshire has fallen sharply: down 52% on the route-weighted index since 1968.

-52%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 Red-winged Blackbird 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 →

Red-winged Blackbird has fallen sharply in New Hampshire: down 52% on the route-weighted index since 1968.

Red-winged Blackbird Population Forecast in New Hampshire

If the recent trend holds, Red-winged Blackbird in New Hampshire is projected to fall about 26% by 2029 — from 13 in 2024 to a central estimate of 9.7 (95% range 2.8–17). A 5-year backtest shows a typical error of ±16.8%, with 100% of held-out values landing inside the 95% band.

-26%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 →
9.7Projected 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 →
2.8–1795% 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 →
±16.8%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, Red-winged Blackbird in New Hampshire is projected to fall about 26% by 2029 — from 13 in 2024 to a central estimate of 9.7 (95% range 2.8–17). A 5-year backtest shows a typical error of ±16.8%, 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 →
2025114.118
2026113.718
2027103.417
202810.03.117
20299.72.817

Red-winged Blackbird Survey Routes in New Hampshire

Routes recording Red-winged Blackbird 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 →
Dover3120241966
Dixville Notch 23020242018
Dixvil Notch2920171966
Canterbury2320241966
Fitzwilliam2220241966
Concord2220241966
Lempster2120241966
East Kingston1920241999
Marlow1720241966
Stratford1720241966
Strafford1220241966
Brentwood1119981966
Walpole1020241966
Crawford Not1019751966
Milan1020241966
Wilmot920241966
Mt Chocorua920241967
Glen820241975
Epsom720231966
Peterborough620241966
Hopkinton520241966
Jefferson Hl520241966
Franconia420241966
Gilmantn I W320241969
Clarksville320241966

Red-winged Blackbird Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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