BirdAnalyst
Guild · Maryland · BBS 2026 Release · 1966–2025

Generalists In Maryland

All statesMaryland

11 species in this guild. As a group they are -58%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 Maryland, down 58% since 1968.

Generalists In Maryland Population Forecast

If the recent trend holds, Generalists in Maryland is projected to fall about 32% by 2030 — from 24 in 2025 to a central estimate of 16 (95% range 9.4–23). A 5-year backtest shows a typical error of ±17.7%, with 100% of held-out values landing inside the 95% band.

-32%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 →
16Projected 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 →
9.4–2395% 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 →
±17.7%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 Maryland is projected to fall about 32% by 2030 — from 24 in 2025 to a central estimate of 16 (95% range 9.4–23). A 5-year backtest shows a typical error of ±17.7%, 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 →
2026191225
2027181125
2028171024
2029179.924
2030169.423

Member Species In Maryland

Generalists species in Maryland.
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 →
House SparrowPasseridae-81%
Common GrackleIcteridae-75%
Rock PigeonColumbidae-60%
European StarlingSturnidae-44%
Northern MockingbirdMimidae-37%
American CrowCorvidae+3%
Mourning DoveColumbidae+28%
Brown-headed CowbirdIcteridae+33%
Fish CrowCorvidae+223%
Common RavenCorvidae78×
House FinchFringillidae82×

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