BirdAnalyst
Guild · Delaware · BBS 2025 Release · 1966–2024

Wetland Birds In Delaware

All statesDelaware

18 species in this guild. As a group they are +99%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 →

No notable trend signals for wetland birds in Delaware. See the full index history below.

Forecast

If the recent trend holds, Wetland birds in Delaware is projected to stay roughly flat through 2029, near 4.7 (95% range 1.1–8.3). A 5-year backtest shows a typical error of ±33.5%, with 80% of held-out values landing inside the 95% band.

+8%Change by 2029TrendPercent 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 →
4.7Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
1.1–8.395% 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 →
±33.5%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, Wetland birds in Delaware is projected to stay roughly flat through 2029, near 4.7 (95% range 1.1–8.3). A 5-year backtest shows a typical error of ±33.5%, with 80% of held-out values landing inside the 95% band.19662029
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 →
20254.61.08.1
20264.61.08.2
20274.61.18.2
20284.71.18.2
20294.71.18.3

Member Species In Delaware

Wetland birds species in Delaware.
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 →
Common TernLaridae-90%
Least TernLaridae-88%
Herring GullLaridae-77%
Great Black-backed GullLaridae-67%
Ring-billed GullLaridae-66%
Western Cattle-EgretArdeidae-46%
Laughing GullLaridae+20%
Little Blue HeronArdeidae+21%
Black-crowned Night HeronArdeidae+34%
Green HeronArdeidae+70%
Double-crested CormorantPhalacrocoracidae+80%
Black SkimmerLaridae+184%
Great EgretArdeidae+404%
Glossy IbisThreskiornithidae+468%
Clapper RailRallidae+547%
Snowy EgretArdeidae23×
Great Blue HeronArdeidae34×
Forster's TernLaridae37×

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.