IDENTIFICATION

Cormorant is the common 

name for 30 species of birds 

that occur world-wide. Six are 

found in North America. The 

most common North American cormorant is the doublecrested cormorant. Adults are 

mostly black with slender 

beaks, long snake-like necks 

and short stiff tails. They often 

use their tail as a prop when 

they perch. They have a 

hooked bill and some birds 

have a yellow-orange throat 

patch. Cormorants have short 

legs and webbed feet for 

swimming. Both the legs and 

feet are black.

HABITS

Cormorants are aquatic birds 

found on inland 

lakes, rivers and 

swamps as well 

as on the coast. 

Double-crested 

cormorants are 

daytime feeders 

that hunt alone 

or in flocks that 

may number 

600 birds. 

Cormorants feed 

by diving and 

swimming underwater. They 

can dive to depths of 5 to 60 

feet below the surface and 

stay under water up to 70 seconds. They eat mostly fish and 

sometimes small invertebrates such as crayfish. Cormorants use their webbed feet 

to propel them underwater. 

Cormorants run along the surface of the water to gain 

enough speed for flight. 

Cormorants have no oil glands 

to grease their feathers and 

repel water. Therefore they 

sometimes perch with their 

wings spread out in the sun 

and breeze to dry their feathers after fishing underwater.

Cormorants are sociable 

birds and almost always nest 

in colonies. Their nests 

consist of sticks and other drift 

material and are built on the 

ground or in trees near water. 

They usually lay three to four 

eggs. Both male and female 

birds share nest-building, incubation and feeding of the 

chicks. The birds have the unusual habit of incubating their 

eggs by wrapping the webs of 

their feet around them. The 

young become fully independent after about ten weeks. 

Improving water quality by preventing pollution has resulted in a thriving cormorant population.

Phalocrocorax auritus

Double-Crested Cormorant

Cormorants are found throughout the northern United States 

and Canada. In the winter 

they are found along the 

coasts and along rivers and 

lakes in the 

central northern states and in 

east Texas and Louisiana.
Living in harmony . . .

Most of the time, cormorants and humans live 

in harmony.

• People enjoy watching these diving birds 

in their natural environment

• Cormorants are an important regulator of 

nature’s complex food web, helping to keep 

fish from overpopulating streams and 

lakes

• Cormorants are an important environmental indicator species —-when 

cormorants are healthy and thriving then 

the environment is healthy and thriving

Living in conflict . . .

• Cormorants consume commercially 

reared fish

• Cormorants destroy trees and natural 

vegetation

• Cormorants can displace desired nesting 

birds and animals

• Cormorants pose hazards to aircraft

• Cormorants can carry diseases that are 

infectious to humans

• Cormorants may eat the same fish that recreational and subsistence fishermen catch

For over 2,000 years the Chinese and Japanese have been using cormorants to help them fish.

Many control methods are used 

to prevent damage caused by 

cormorants. Both lethal and 

non-lethal methods are used. 

Often a combination of methods 

works the best. Using a combination of management methods is 

called integrated pest management (IPM). The purpose of IPM 

is to reduce damage done by the 

birds rather than eliminate cormorants. 

Some non-lethal methods 

include:

• completely or partially 

enclosing small ponds with 

screen, netting or overhead 

wire

• using frightening devices 

such as pyrotechnics 

(projectile firecrackers), 

eyespot balloons, automatic 

exploders, scarecrows, flash 

tape, distress call units, 

sirens/horns and vehicles. 

• relocating winter roosts away 

from aquaculture sites 

• providing alternate food 

sources

• modifying aquaculture 

practices

Some lethal control methods that 

might be used after obtaining 

permission from both state and 

federal agencies include:

• shooting cormorants 

• egg oiling or removing eggs

• nest removal
The cost of frightening programs varies depending on the 

types of techniques used, the species of birds involved, 

the size of the farm and road conditions. Following is an 

example of daily cost for a typical scaring program on a 

farm of 500 acres of ponds. 

Labor (10 hours @ $8.00/hour) $ 80.00

Vehicle expense (100 miles @ $.30/mi) $ 30.00

Pyrotechnics & Ammunition $ 16.30

 (used to scare birds)

 Total Costs: $126.30

How much would a frightening program cost at a farm for 

150 days? 

What would the costs be for the following farm?

Labor (15 hours @ $9/hr) _________

Vehicle Expense (250 miles @ $.25/mile) _________

Pyrotechnics 

 (200 rounds @ $36.50/100 rounds) _________

Ammunition for harassment

 (25 rounds @$5.24/25 rounds _________

What is the daily total? _________

How much would it cost for 90 days? _________

Aquaculture, fish farming, is the raising and selling 

of fish for profit. Aquaculture is one of the fastest 

growing industries in the U.S. Catfish, trout, 

salmon, striped bass and ornamental fish are the 

most common fish raised. Cormorants hunt where 

there are a lot of fish. This is exactly what the cormorants find at fish farms. The aquaculture industry 

loses millions of dollars worth of fish to cormorants. 

In Mississippi, cormorants have been reported to 

eat more than $3 million dollars worth of catfish 

each year. Producers spend more than $2 million 

trying to prevent damage. 

ACROSS: 2 – catfish, 3 – aquaculture, 4 cormorant, 5 – environmental indicator, 

7 – integrated pest management, 8 – invertebrate

 DOWN: 1 – pyrotechnics, 2. colonies, 3. aquatic, 6. webbed 

The word “cormorant” comes from the Latin name 

corvus marinus which means “sea crow.” Other 

names used for the double-crested cormorant are 

water turkey, water buzzard, crow-duck, Farallon 

cormorant, Florida cormorant, shag, Taunton 

turkey and white-crested cormorant. 

In Asian countries, the cormorant is used to 

harvest fish. A ring is placed around the bird’s neck 

so it cannot swallow the fish. The cormorant dives 

into the water, catches the fish and brings it back to 

the boat where the handler grabs the fish.

Double-crested cormorants were abundant during 

the 1940s. However, the numbers of cormorants 

declined in the 1960s and 1970s. This decline was 

due to humans collecting eggs for food and destroying the birds’ nests. Contaminants in the water 

and food supply are also believed to have lowered 

their numbers. In 1972 the double-crested cormorant was added to the list of species protected under the Migratory Bird Treaty Act. By the 1980s 

most cormorant populations began to increase. 

This increase was due to reducing human persecution, reducing levels of environmental contaminants, especially DDT, an abundant supply of fish 

(in part from the expanding aquaculture industry), 

and development of good colony sites on manmade lakes. Today, cormorant populations are at 

an all-time high.

Calculating the cost . . .
This activity sheet has been developed by USDA Wildlife Services. For more information about cormorants 

contact your state’s Wildlife Services office or USDA Wildlife Services at 301 734-7921. 

Wildlife Activity Book and

1998 Wildlife Issue of the

Colorado Reader

Colorado Foundation for 

Agriculture 

P.O. Box 10

Livermore, CO 80536

Jack H. Berryman Institute

for Wildlife Damage 

Management

Utah State University

Logan, Utah 83431-5210

Websites:

Cc.usu.edu/~rschmidt/welcom.

html

USGS Patuxent Wildlife Research Center Bird Identification: www.mbr-pwrc.usgs.gov

ACROSS

2. A type of fish raised in farms 

3. Another word for fish farming

4. Common name for several web-footed black 

birds with slender beaks

5. When the decline in the number of a species of 

animals indicates pollution or other problems in 

the environment

7. What IPM stands for

8. Crayfish is an example of this type of animal

DOWN

1. Firecrackers are an example of this

2. Groups of birds nesting together are called...

3. Having to do with water

6. This type of foot makes it easier for birds to 

swim

 1 2

 3

 4

 5

 6

 7

 8