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

Wetland Birds In Vermont

All statesVermont

11 species in this guild. As a group they are -61%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 Vermont, down 61% since 1968.

Wetland Birds In Vermont Population Forecast

If the recent trend holds, Wetland birds in Vermont is projected to fall about 42% by 2030 — from 4.5 in 2025 to a central estimate of 2.6 (95% range 0.00–5.5). A 5-year backtest shows a typical error of ±18.1%, with 100% of held-out values landing inside the 95% band.

-42%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 →
2.6Projected 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 →
0.00–5.595% 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 →
±18.1%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, Wetland birds in Vermont is projected to fall about 42% by 2030 — from 4.5 in 2025 to a central estimate of 2.6 (95% range 0.00–5.5). A 5-year backtest shows a typical error of ±18.1%, 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 →
20263.20.306.1
20273.10.166.0
20282.90.015.8
20292.80.005.7
20302.60.005.5

Member Species In Vermont

Wetland birds species in Vermont.
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 →
Green HeronArdeidae-72%
Virginia RailRallidae-64%
Red-winged BlackbirdIcteridae-64%
Belted KingfisherAlcedinidae-42%
Double-crested CormorantPhalacrocoracidae-42%
Herring GullLaridae-31%
American BitternArdeidae-17%
Great Blue HeronArdeidae+2%
Swamp SparrowPasserellidae+56%
Common LoonGaviidae+291%
Ring-billed GullLaridae12×

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