BirdAnalyst
Species · BCR 27 · BBS 2025 Release · 1966–2024

Double-crested Cormorant In Southeastern Coastal Plain

All regionsSoutheastern Coastal PlainWetland birds

Double-crested Cormorant in Southeastern Coastal Plain has surged: up 16× on the route-weighted index since 1969.

16×Since 1969TrendPercent 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 →
113Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
55YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable 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 →

Double-crested Cormorant has surged in Southeastern Coastal Plain: up 16× on the route-weighted index since 1969.

Double-crested Cormorant In Southeastern Coastal Plain Population Forecast

If the recent trend holds, Double-crested Cormorant in Southeastern Coastal Plain is projected to rise about 171% by 2029 — from 0.10 in 2024 to a central estimate of 0.28 (95% range 0.01–0.55). A 5-year backtest shows a typical error of ±158.9%, with 80% of held-out values landing inside the 95% band.

+171%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 →
0.28Projected 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 →
0.01–0.5595% 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 →
±158.9%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 Southeastern Coastal Plain is projected to rise about 171% by 2029 — from 0.10 in 2024 to a central estimate of 0.28 (95% range 0.01–0.55). A 5-year backtest shows a typical error of ±158.9%, 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 →
20250.270.000.54
20260.270.000.54
20270.270.000.54
20280.280.010.55
20290.280.010.55

Routes In Southeastern Coastal Plain

Routes recording Double-crested Cormorant in Southeastern Coastal Plain.
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 →
Maple HillNORTH-CAROLINA272023
CastleberryALABAMA232008
WashingtonNORTH-CAROLINA162021
Adams RunSOUTH-CAROLINA151999
HertfordNORTH-CAROLINA122013
SupplyNORTH-CAROLINA112021
Ft Waltn BchFLORIDA82008
MashoesNORTH-CAROLINA81982
Big SandyTENNESSEE82024
KinstonNORTH-CAROLINA72016
WedgeworthALABAMA62002
NashvilleGEORGIA62002
Rock ChapelALABAMA52002
Hixtown SwmpFLORIDA52015
DortchesNORTH-CAROLINA52015
JarvisburgNORTH-CAROLINA51999
BranchvilleVIRGINIA51999
Dauphin Is 2ALABAMA42018
MerrimonNORTH-CAROLINA42021
St FlorianALABAMA31999
GreensboroALABAMA32012
MiccosukeeFLORIDA32000
PinettaFLORIDA32024
Cross CityFLORIDA32021
OkefenokeeGEORGIA31991

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