BirdAnalyst
Species · BCR 29 · BBS 2025 Release · 1966–2024

Double-crested Cormorant In Piedmont

All regionsPiedmontWetland birds

Double-crested Cormorant in Piedmont has held roughly steady: down 0% on the route-weighted index since 1987.

-0%Since 1987TrendPercent 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 →
40Routes 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 →
37YearsYears 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 →

No notable trend signals for Double-crested Cormorant in Piedmont. See the full index history below.

Forecast

If the recent trend holds, Double-crested Cormorant in Piedmont is projected to stay roughly flat through 2029, near 0.10 (95% range 0.00–0.28). A 5-year backtest shows a typical error of ±281.4%, with 80% of held-out values landing inside the 95% band.

n/aChange 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 →
0.10Projected 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 →
0.00–0.2895% 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 →
±281.4%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, Double-crested Cormorant in Piedmont is projected to stay roughly flat through 2029, near 0.10 (95% range 0.00–0.28). A 5-year backtest shows a typical error of ±281.4%, with 80% of held-out values landing inside the 95% band.19772029
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 →
20250.100.000.28
20260.100.000.28
20270.100.000.28
20280.100.000.28
20290.100.000.28

Routes In Piedmont

Routes recording Double-crested Cormorant in Piedmont.
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 →
BrodnaxVIRGINIA362021
Upper XrdsMARYLAND132005
SawmillNORTH-CAROLINA62001
SiloamGEORGIA32019
EkloMARYLAND32008
Mount JoyPENNSYLVANIA32011
Brick TavernPENNSYLVANIA32012
RinggoldVIRGINIA32013
OlneyMARYLAND22019
TheodoreMARYLAND22016
IjamsvilleMARYLAND22013
ArcolaNORTH-CAROLINA22022
WacoNORTH-CAROLINA22000
OsmondNORTH-CAROLINA22002
Carters BrdgVIRGINIA21997
WedoweeALABAMA12006
CrestGEORGIA11994
AthensGEORGIA12018
StockbridgeGEORGIA12000
JulietteGEORGIA11991
WoodstockGEORGIA12007
EmmitsburgMARYLAND12024
Van BibberMARYLAND12002
EarltonMARYLAND12018
SandbrookNEW-JERSEY12023

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