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

Black Vulture Population Trend in Delaware

All statesGeneralists

Black Vulture in Delaware has surged: up 807% on the route-weighted index since 1973.

+807%Since 1973TrendPercent 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 →
16Routes 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 →
43YearsYears 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 Vulture 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 Vulture has surged in Delaware: up 807% on the route-weighted index since 1973.

Black Vulture Population Forecast in Delaware

If the recent trend holds, Black Vulture in Delaware is projected to rise about 72% by 2029 — from 1.8 in 2024 to a central estimate of 3.1 (95% range 1.2–5.0). A 5-year backtest shows a typical error of ±28.4%, with 80% of held-out values landing inside the 95% band.

+72%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 →
3.1Projected 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 →
1.2–5.095% 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 →
±28.4%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 Vulture in Delaware is projected to rise about 72% by 2029 — from 1.8 in 2024 to a central estimate of 3.1 (95% range 1.2–5.0). A 5-year backtest shows a typical error of ±28.4%, with 80% of held-out values landing inside the 95% band.19712029
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 →
20252.80.954.7
20262.91.04.8
20273.01.14.9
20283.01.14.9
20293.11.25.0

Black Vulture Survey Routes in Delaware

Routes recording Black Vulture 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 →
Milton1220151984
Frederica520141992
Millsboro520212017
Pepperbox 2520242017
Holleyville 2420192015
Milton 2420172017
Harrington320241980
Georgetown320221999
Mt Pleasant220161971
Holleyville220041975
Lowes Xrds219731972
Wilmington120142000
Dover119851985
Frankford120121971
Blackbird120241999
Pepperbox120162000

Black Vulture Population Trend in Other States

alabamaarizonaarkansasconnecticutfloridageorgiaillinoisindianakentuckylouisianamarylandmassachusettsmississippimissourinew-jerseynew-yorknorth-carolinaohiooklahomapennsylvaniasouth-carolinatennesseetexasvermontvirginiawest-virginia

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