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

Generalists In Maine

All statesMaine

10 species in this guild. As a group they are -63%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 Maine, down 63% since 1968.

Generalists In Maine Population Forecast

If the recent trend holds, Generalists in Maine is projected to fall about 46% by 2030 — from 6.7 in 2025 to a central estimate of 3.6 (95% range 0.00–8.5). A 5-year backtest shows a typical error of ±54.5%, with 60% of held-out values landing inside the 95% band.

-46%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 →
3.6Projected 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 →
0.00–8.595% 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 →
±54.5%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 Maine is projected to fall about 46% by 2030 — from 6.7 in 2025 to a central estimate of 3.6 (95% range 0.00–8.5). A 5-year backtest shows a typical error of ±54.5%, with 60% 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 →
20264.40.009.3
20274.20.009.1
20284.00.008.9
20293.80.008.7
20303.60.008.5

Member Species In Maine

Generalists species in Maine.
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-89%
Brown-headed CowbirdIcteridae-83%
Common GrackleIcteridae-68%
House SparrowPasseridae-52%
Northern MockingbirdMimidae-33%
Common RavenCorvidae-22%
American CrowCorvidae+56%
Rock PigeonColumbidae+274%
House FinchFringillidae+512%
Mourning DoveColumbidae21×

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