Double-crested Cormorant

Phalacrocorax auritus

Copyright, Dan Sudia

Double-crested Cormorants are large birds, growing over two feet long, with a wingspan of four feet.

They are mostly black with an orange throat. They have a long neck and webbed feet.

During breeding season, males have two curly black crests on their heads.

Cormorants are water birds, and are found at lakes, rivers, streams, marshes, bays, and coasts. They are great swimmers and divers, as well as good flyers.

Double-crested Cormorants usually travel, feed, and roost in groups.

In breeding season, cormorants gather in colonies and build nests out of sticks, twigs, feathers, grass, bark, and trash. They have been known to also include pebbles and parts of dead birds.

Copyright, Pedro Genaro Rodriquez

Nests are built on the ground, or in shrubs or trees. Female cormorants lay 3 to 5 bluish-green eggs. Both parents care for eggs and chicks. Adults return from feeding and regurgitate (throw up) food into the chicks' mouths.

Cormorants can fly about 6 weeks after hatching. Young cormorants gather in a group called a "creche." They are browner in color than adults and will get darker as they get older.

Cormorants usually live around 6 years, but can live much longer.

Double-crested Cormorants migrate in Fall and Spring, though some are around in our area year-round.

Double-crested Cormorants eat mostly fish. They dive underwater and hunt along the bottom. They eat a great variety of fish species, as well as other animals including: crayfish, shrimp, aquatic insects, amphibians (such as tadpoles and newts), snails, mussels, and some reptiles.

Small fish are eaten immediately. Larger fish are taken to the surface where the cormorant flips it and swallows it head first.

After feeding, cormorants need to dry their wings. They do not have oil in their skin to protect their feathers from getting wet, like ducks and othe water birds do. Cormorants find a perch and stretch their wings out until they are dry.

Double-crested Cormorants often associate with other birds. Nests are built in trees alongside Great Blue Herons and other heron species. They will even use old heron nests as their own. Cormorants will feed with other water birds, such as gulls, ducks, and herons. These birds help each other with finding food and watching for predators.

Predators of cormorant eggs and chicks include gulls, crows, Blue Jay, Common Grackle, Raccoon, Red Fox, and Coyote. Adult cormorants are preyed on by Bald Eagle and Great Horned Owl.

When threatened, a Doulbe-crested Cormorant may vomit fish at a predator.

Double-crested Cormorants can damage or kill trees they nest in, as well as smaller trees, shrubs, and other plants underneath nests. They do this by pooping on the branches. Since many cormorants nest together, the poop adds up quickly and harms the plants.

Relationships in Nature:

FOOD/PREY
PREDATORS
SHELTER
OTHER

American Eel

Ring-billed Gull

American Sycamore

Great Blue Heron Mu SP

Yellow Perch

American Crow

Black Willow

Hooded Merganser Mu

Creek Chub

Blue Jay

Red Maple

Ring-billed Gull Mu

Golden Shiner

Common Grackle

Yellow Poplar

Tesselated Darter

Raccoon

White Oak

Channel Catfish

Red Fox

Sweetgum

Bluegill

Bald Eagle

Switchgrass

Largemouth Bass

Great Horned Owl

Kentucky Bluegrass

Crayfish

Wild Grape

Bullfrog

Eastern Redcedar

Eastern Lamp Mussel

Stagnant Pond Snail

Northern Water Snake

Common Snapping Turtle

Eastern Painted Turtle

Green Darner

Large Diving Beetle

Eastern Dobsonfly

Crane Fly

Yellow Bullhead

Relationship to Humans:

Some fishermen and fish farmers used to accuse cormorants of killing too many fish. Studies have proven that comorants don't do much harm. They eat mostly small fish, and this can actually help fish populations by eliminating slower, weaker fish, allowing others to grow larger. People often kill cormorants in fishing nets and oil spills. Also, pesticides (chemicals used with farming) can weaken eggshells, killing them. Double-crested Cormorants are known to carry some fish diseases and parasites.

SCIENTIFIC CLASSIFICATION

KINGDOM
Animal
PHYLUM
Chordate
CLASS
Bird
ORDER
Pelicaniformes
FAMILY
Phalacrocoracidae
GENUS
Phalacrocorax
SPECIES
Phalacrocorax auritus

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