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

Generalists In New Jersey

All statesNew Jersey

11 species in this guild. As a group they are -62%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 Jersey, down 62% since 1968.

Generalists In New Jersey Population Forecast

If the recent trend holds, Generalists in New Jersey is projected to fall about 29% by 2030 — from 15 in 2025 to a central estimate of 11 (95% range 4.1–17). A 5-year backtest shows a typical error of ±11.1%, with 100% of held-out values landing inside the 95% band.

-29%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 →
11Projected 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 →
4.1–1795% 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 →
±11.1%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 Jersey is projected to fall about 29% by 2030 — from 15 in 2025 to a central estimate of 11 (95% range 4.1–17). A 5-year backtest shows a typical error of ±11.1%, 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 →
2026136.520
2027135.919
2028125.319
2029114.718
2030114.117

Member Species In New Jersey

Generalists species in New Jersey.
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 →
Common GrackleIcteridae-82%
Northern MockingbirdMimidae-69%
House SparrowPasseridae-66%
Rock PigeonColumbidae-61%
European StarlingSturnidae-56%
American CrowCorvidae+1%
Mourning DoveColumbidae+11%
Brown-headed CowbirdIcteridae+156%
Fish CrowCorvidae+284%
Common RavenCorvidae+721%
House FinchFringillidae77×

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