BirdAnalyst
Species · BCR 12 · BBS 2025 Release · 1966–2024

Double-crested Cormorant In Boreal Hardwood Transition

All regionsBoreal Hardwood TransitionWetland birds

Double-crested Cormorant in Boreal Hardwood Transition has collapsed: down 78% on the route-weighted index since 1982.

-78%Since 1982
33Routes In Region
38Years

Notable Signals

long arc declinecomputed index

Double-crested Cormorant has collapsed in Boreal Hardwood Transition: down 78% on the route-weighted index since 1982.

Forecast

If the recent trend holds, Double-crested Cormorant in Boreal Hardwood Transition is projected to stay roughly flat through 2029, near 0.12 (95% range 0.00–1.0). A 5-year backtest shows a typical error of ±564.3%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2029
0.12Projected 2029 index
0.00–1.095% range
±564.3%Backtest error
19782029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected index95% low95% high
20250.140.001.1
20260.130.001.1
20270.130.001.1
20280.120.001.0
20290.120.001.0

Routes In Boreal Hardwood Transition

Routes recording Double-crested Cormorant in Boreal Hardwood Transition.
Hart LakeMINNESOTA381997
McgregorMINNESOTA241993
Pine RiverMINNESOTA221991
IsabellaMICHIGAN51988
CromwellMINNESOTA52001
BootjackMICHIGAN31998
Cass LakeMINNESOTA31990
Nett LakeMINNESOTA32016
Maple GroveMICHIGAN21992
IshpemingMICHIGAN21991
CathroMICHIGAN21995
Island LakeMINNESOTA21989
GreenbushMINNESOTA21996
PhillipsWISCONSIN21993
HermanMICHIGAN11993
MuskallongeMICHIGAN11997
PickfordMICHIGAN12000
Mille LacsMINNESOTA12024
Sherry LakeMINNESOTA11989
DebsMINNESOTA12010
LudeMINNESOTA11981
BrainerdMINNESOTA12004
NebishMINNESOTA11991
Tamarac NwrMINNESOTA12004
Iron RiverWISCONSIN12000

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