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

Generalists In New Hampshire

All statesNew Hampshire

11 species in this guild. As a group they are -52%Guild trendA mean-index aggregate across the species in this group — the structural direction of the guild, with individual-species noise smoothed out.Full methodology → since 1968.

Guild SignalsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

guild collapsecomputed 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 →

Generalists as a group have fallen sharply in New Hampshire, down 52% since 1968.

Generalists In New Hampshire Population Forecast

If the recent trend holds, Generalists in New Hampshire is projected to stay roughly flat through 2030, near 5.1 (95% range 3.2–7.0). A 5-year backtest shows a typical error of ±4%, with 100% of held-out values landing inside the 95% band.

-7%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 →
5.1Projected 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 →
3.2–7.095% 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 →
±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, Generalists in New Hampshire is projected to stay roughly flat through 2030, near 5.1 (95% range 3.2–7.0). A 5-year backtest shows a typical error of ±4%, 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 →
20265.63.77.5
20275.53.67.4
20285.43.57.3
20295.33.47.2
20305.13.27.0

Member Species In New Hampshire

Generalists species in New Hampshire.
TrendPercent 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 →
European StarlingSturnidae-81%
Brown-headed CowbirdIcteridae-62%
Rock PigeonColumbidae-59%
Common GrackleIcteridae-53%
House SparrowPasseridae-39%
American CrowCorvidae+55%
Fish CrowCorvidae+70%
Mourning DoveColumbidae+282%
House FinchFringillidae+881%
Northern MockingbirdMimidae+933%
Common RavenCorvidae+951%

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