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

Common Grackle Population Trend in New Hampshire

All statesGeneralists

Common Grackle 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 Common Grackle 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 →

Common Grackle has fallen sharply in New Hampshire: down 52% on the route-weighted index since 1968.

Common Grackle Population Forecast in New Hampshire

If the recent trend holds, Common Grackle in New Hampshire is projected to fall about 60% by 2029 — from 7.0 in 2024 to a central estimate of 2.8 (95% range 0.00–6.7). A 5-year backtest shows a typical error of ±30.2%, with 100% of held-out values landing inside the 95% band.

-60%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 →
2.8Projected 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 →
0.00–6.795% 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 →
±30.2%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, Common Grackle in New Hampshire is projected to fall about 60% by 2029 — from 7.0 in 2024 to a central estimate of 2.8 (95% range 0.00–6.7). A 5-year backtest shows a typical error of ±30.2%, 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 →
20253.70.007.6
20263.50.007.4
20273.20.007.1
20283.00.006.9
20292.80.006.7

Common Grackle Survey Routes in New Hampshire

Routes recording Common Grackle 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 →
Concord1720241966
Walpole1720241966
Canterbury1520241966
Milan1420241966
Epsom1020231966
Stratford1020241966
Clarksville1020241966
Marlow920241966
Dover820241966
Dixvil Notch820171967
Strafford720241966
East Kingston720241999
Peterborough620241966
Lempster620241966
Dixville Notch 2620242018
Brentwood419981966
Franconia420241966
Hopkinton320241966
Mt Chocorua320241966
Jefferson Hl320241966
Glen320241975
Fitzwilliam220241966
Wilmot220241966
Crawford Not219751966
Gilmantn I W120221969

Common Grackle Population Trend in Other States

alabamaarkansascoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawest-virginiawisconsinwyoming

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