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Species · Delaware · BBS 2025 Release · 1966–2024

Black Skimmer Population Trend in Delaware

All statesWetland birds

Black Skimmer in Delaware has surged: up 184% on the route-weighted index since 1968.

+184%Since 1968TrendPercent 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 →
6Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
33YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Black Skimmer Trends in DelawareNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

long arc increasecomputed 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 →

Black Skimmer has surged in Delaware: up 184% on the route-weighted index since 1968.

Black Skimmer Population Forecast in Delaware

If the recent trend holds, Black Skimmer in Delaware is projected to fall about 73% by 2028 — from 3.5 in 2023 to a central estimate of 0.94 (95% range 0.00–3.0). A 5-year backtest shows a typical error of ±103.8%, with 80% of held-out values landing inside the 95% band.

-73%Change by 2028TrendPercent 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 →
0.94Projected 2028 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–3.095% 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 →
±103.8%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, Black Skimmer in Delaware is projected to fall about 73% by 2028 — from 3.5 in 2023 to a central estimate of 0.94 (95% range 0.00–3.0). A 5-year backtest shows a typical error of ±103.8%, with 80% of held-out values landing inside the 95% band.19662028
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 →
20240.940.003.0
20250.940.003.0
20260.940.003.0
20270.940.003.0
20280.940.003.0

Black Skimmer Survey Routes in Delaware

Routes recording Black Skimmer in Delaware.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
Blackbird1420231995
Bethany Bch1019901966
Dover619731968
Georgetown220172017
Harrington120141974
Lowes Xrds119871985

Black Skimmer Population Trend in Other States

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