BirdAnalyst
Species · New Hampshire · BBS 2026 Release · 1966–2025

Rose-breasted Grosbeak Population Trend in New Hampshire

All statesForest birds

Rose-breasted Grosbeak in New Hampshire has fallen sharply: down 56% on the route-weighted index since 1968.

-56%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 →
59YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Rose-breasted Grosbeak 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 →

Rose-breasted Grosbeak has fallen sharply in New Hampshire: down 56% on the route-weighted index since 1968.

Rose-breasted Grosbeak Population Forecast in New Hampshire

If the recent trend holds, Rose-breasted Grosbeak in New Hampshire is projected to fall about 36% by 2030 — from 1.2 in 2025 to a central estimate of 0.78 (95% range 0.00–3.0). A 5-year backtest shows a typical error of ±6%, with 100% of held-out values landing inside the 95% band.

-36%Change by 2030TrendPercent 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 →
0.78Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–3.095% 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 →
±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, Rose-breasted Grosbeak in New Hampshire is projected to fall about 36% by 2030 — from 1.2 in 2025 to a central estimate of 0.78 (95% range 0.00–3.0). A 5-year backtest shows a typical error of ±6%, with 100% of held-out values landing inside the 95% band.19662030
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 →
20261.10.003.3
20270.980.003.2
20280.920.003.1
20290.850.003.1
20300.780.003.0

Rose-breasted Grosbeak Survey Routes in New Hampshire

Routes recording Rose-breasted Grosbeak 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 →
Walpole420251966
East Kingston420251999
Epsom320211966
Concord320251966
Strafford320251966
Marlow320251967
Brentwood219981966
Canterbury220251967
Wilmot220251966
Jefferson Hl220251966
Franconia220231966
Glen220241976
Peterborough120241966
Fitzwilliam120251966
Dover120251966
Hopkinton120251966
Gilmantn I W120241969
Mt Chocorua120251969
Lempster120251966
Crawford Not119751967
Milan120231969
Stratford120221966
Dixvil Notch120151967
Clarksville120231968
Jeffers Ntch120121993

Rose-breasted Grosbeak Population Trend in Other States

arkansasconnecticutgeorgiaillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamissourinebraskanew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-dakotatennesseevermontvirginiawest-virginiawisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.