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

Wetland Birds In Maine

All statesMaine

16 species in this guild. As a group they are -66%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 →

Wetland birds as a group have fallen sharply in Maine, down 66% since 1968.

Wetland Birds In Maine Population Forecast

If the recent trend holds, Wetland birds in Maine is projected to fall about 83% by 2030 — from 1.6 in 2025 to a central estimate of 0.27 (95% range 0.00–1.9). A 5-year backtest shows a typical error of ±83.7%, with 60% of held-out values landing inside the 95% band.

-83%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 →
0.27Projected 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 →
0.00–1.995% 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 →
±83.7%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, Wetland birds in Maine is projected to fall about 83% by 2030 — from 1.6 in 2025 to a central estimate of 0.27 (95% range 0.00–1.9). A 5-year backtest shows a typical error of ±83.7%, 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 →
20260.510.002.2
20270.450.002.1
20280.390.002.0
20290.330.002.0
20300.270.001.9

Member Species In Maine

Wetland birds 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 →
Herring GullLaridae-90%
Rusty BlackbirdIcteridae-88%
Virginia RailRallidae-83%
Green HeronArdeidae-78%
Black-crowned Night HeronArdeidae-66%
American BitternArdeidae-66%
Red-winged BlackbirdIcteridae-65%
Common TernLaridae-62%
Belted KingfisherAlcedinidae-58%
Great Black-backed GullLaridae-44%
Great Blue HeronArdeidae-17%
Double-crested CormorantPhalacrocoracidae+42%
Swamp SparrowPasserellidae+51%
Ring-billed GullLaridae+56%
Pied-billed GrebePodicipedidae+62%
Common LoonGaviidae+83%

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