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Species · Virginia · BBS 2026 Release · 1966–2025

Double-crested Cormorant Population Trend in Virginia

All statesWetland birds

Double-crested Cormorant in Virginia has collapsed: down 81% on the route-weighted index since 1985.

-81%Since 1985TrendPercent 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 →
20Routes 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 →
35YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Double-crested Cormorant Trends in VirginiaNotable 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 declinecomputed 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 →

Double-crested Cormorant has collapsed in Virginia: down 81% on the route-weighted index since 1985.

Double-crested Cormorant Population Forecast in Virginia

If the recent trend holds, Double-crested Cormorant in Virginia is projected to stay roughly flat through 2030, near 0.37 (95% range 0.00–1.1). A 5-year backtest shows a typical error of ±705.9%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.37Projected 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 →
0.00–1.195% 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 →
±705.9%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, Double-crested Cormorant in Virginia is projected to stay roughly flat through 2030, near 0.37 (95% range 0.00–1.1). A 5-year backtest shows a typical error of ±705.9%, with 100% of held-out values landing inside the 95% band.19772030
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 →
20260.350.001.0
20270.360.001.0
20280.360.001.0
20290.370.001.0
20300.370.001.1

Double-crested Cormorant Survey Routes in Virginia

Routes recording Double-crested Cormorant in Virginia.
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 →
Brodnax3620211977
Port Royal2420191991
Sharps1320131994
Cape Charles1220181997
Chincoteag W1020221992
Branchville519991999
Colonial Pky319981992
Ringgold320132013
Brandon220051995
Carters Brdg219971997
Gloucester120132002
Covesville119971989
Hall120132013
White Stone120251982
Quinby120061985
Cornland120102010
Pungo120231995
Finchley120142009
Gladys119951995
Taylorstown 2120152015

Double-crested Cormorant Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontwashingtonwest-virginiawisconsinwyoming

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