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

Wetland Birds In Massachusetts

All statesMassachusetts

16 species in this guild. As a group they are -65%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 Massachusetts, down 65% since 1968.

Wetland Birds In Massachusetts Population Forecast

If the recent trend holds, Wetland birds in Massachusetts is projected to fall about 72% by 2030 — from 3.0 in 2025 to a central estimate of 0.86 (95% range 0.00–3.9). A 5-year backtest shows a typical error of ±79.7%, with 60% of held-out values landing inside the 95% band.

-72%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 →
0.86Projected 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 →
0.00–3.995% 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 →
±79.7%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 Massachusetts is projected to fall about 72% by 2030 — from 3.0 in 2025 to a central estimate of 0.86 (95% range 0.00–3.9). A 5-year backtest shows a typical error of ±79.7%, 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 →
20261.20.004.3
20271.10.004.2
20281.00.004.1
20290.950.004.0
20300.860.003.9

Member Species In Massachusetts

Wetland birds species in Massachusetts.
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-98%
Ring-billed GullLaridae-93%
Snowy EgretArdeidae-87%
Common TernLaridae-76%
Great Black-backed GullLaridae-62%
Least TernLaridae-60%
Black-crowned Night HeronArdeidae-39%
American BitternArdeidae-28%
Belted KingfisherAlcedinidae-28%
Red-winged BlackbirdIcteridae-26%
Green HeronArdeidae-21%
Laughing GullLaridae-17%
Double-crested CormorantPhalacrocoracidae+2%
Great EgretArdeidae+21%
Swamp SparrowPasserellidae+87%
Great Blue HeronArdeidae12×

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