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

Red Crossbill Population Trend in New Hampshire

All statesGeneralists

Red Crossbill in New Hampshire has surged: up 146% on the route-weighted index since 1971.

+146%Since 1971TrendPercent 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 →
15Routes 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 Red Crossbill 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 increasecomputed 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 Crossbill has surged in New Hampshire: up 146% on the route-weighted index since 1971.

Red Crossbill Population Forecast in New Hampshire

If the recent trend holds, Red Crossbill in New Hampshire is projected to fall about 23% by 2029 — from 0.23 in 2024 to a central estimate of 0.17 (95% range 0.00–1.1). A 5-year backtest shows a typical error of ±67.6%, with 100% of held-out values landing inside the 95% band.

-23%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 →
0.17Projected 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 →
0.00–1.195% 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 →
±67.6%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, Red Crossbill in New Hampshire is projected to fall about 23% by 2029 — from 0.23 in 2024 to a central estimate of 0.17 (95% range 0.00–1.1). A 5-year backtest shows a typical error of ±67.6%, with 100% of held-out values landing inside the 95% band.19672029
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 →
20250.190.001.2
20260.180.001.1
20270.180.001.1
20280.180.001.1
20290.170.001.1

Red Crossbill Survey Routes in New Hampshire

Routes recording Red Crossbill 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 →
Jefferson Hl920151977
Walpole520232023
Stratford420192019
Concord320232023
Wilmot320231976
Mt Chocorua220241970
Milan219921973
Clarksville220031975
Dover120002000
Strafford119861986
Canterbury120242022
Marlow120242024
Franconia119861967
Dixvil Notch119751970
Glen120241976

Red Crossbill Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradogeorgiaidahoillinoismainemarylandmassachusettsmichiganminnesotamontananebraskanevadanew-mexiconew-yorknorth-carolinanorth-dakotaoregonpennsylvaniasouth-carolinasouth-dakotatennesseeutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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