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

Waterfowl In Delaware

All statesDelaware

4 species in this guild. As a group they are 22×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 waterfowl in Delaware. See the full index history below.

Waterfowl In Delaware Population Forecast

If the recent trend holds, Waterfowl in Delaware is projected to fall about 41% by 2029 — from 16 in 2024 to a central estimate of 9.5 (95% range 4.1–15). A 5-year backtest shows a typical error of ±48.7%, with 80% of held-out values landing inside the 95% band.

-41%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 →
9.5Projected 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 →
4.1–1595% 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 →
±48.7%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, Waterfowl in Delaware is projected to fall about 41% by 2029 — from 16 in 2024 to a central estimate of 9.5 (95% range 4.1–15). A 5-year backtest shows a typical error of ±48.7%, 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 →
20258.93.514
20269.03.614
20279.23.815
20289.44.015
20299.54.115

Member Species In Delaware

Waterfowl 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 →
MallardAnatidae+20%
American Black DuckAnatidae+45%
Wood DuckAnatidae+73%
Canada GooseAnatidae54×

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