Herons and Bitterns: Ardeidae

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HERONS AND BITTERNS: Ardeidae

GREAT BLUE HERON (Ardea herodias): SPECIES ACCOUNTS
CATTLE EGRET (Egretta ibis): SPECIES ACCOUNTS
EURASIAN BITTERN (Botaurus stellaris): SPECIES ACCOUNTS

PHYSICAL CHARACTERISTICS

Herons, egrets, and bitterns are medium to very large wading birds, birds with long legs who walk through shallow water searching for prey. They are 9.7 to 58.5 inches (25 to 150 centimeters) long from beak to tail, and they weigh between 0.16 and 9.9 pounds (73 grams and 4.5 kilograms). They have long necks, which they fold over their backs when flying, and long legs and toes. With the exception of the boat-billed heron, which has a wide, flat bill, these birds all have long, sharply-pointed bills, large eyes, and broad wings.

The birds in the heron, egret, and bittern family have feathers that are combinations of the colors black, gray, brown, and white. They have a comblike claw on each of their middle toes that they use for smoothing their feathers. Another way they keep their feathers in good shape is by putting powder on them. It comes from feathers called powder downs. These are special feathers that turn to powder instead of dropping off. At breeding time, both males and females grow long, showy feathers on their heads, necks, and backs.

GEOGRAPHIC RANGE

Herons, egrets, and bitterns live on all continents except Antarctica. They also live on islands in all oceans. Many of these birds prefer warm climates, and they live in the tropics year round. The birds that nest in the cooler areas of the world usually migrate in spring and fall.

HABITAT

Herons, egrets, and bitterns usually live in wetlands, including swamps, tidal areas (where saltwater and fresh water mix), marshes, damp meadows, and forest streams. Most of them feed in water, but they like to have trees nearby for roosting at night and for their nests. Some also live in grasslands, farm fields, or rice fields, and a few kinds are able to live in drier areas.


DIET

Herons, egrets, and bitterns are carnivorous, eating only meat, and most of them eat fish. They wade in shallow water looking for prey, animals they eat, and with a rapid thrust of their long, sharp bills they capture fish. They also eat crabs and other crustaceans, frogs, insects, snails, small mammals, small birds, and reptiles.


BEHAVIOR AND REPRODUCTION

Many kinds of herons and egrets gather in huge flocks to feed together and roost at night. They also nest in groups called colonies that can number from a few birds to thousands. Bitterns are more likely to keep to themselves. The females usually build nests with sticks brought by their mates. Except for bitterns, both parents take turns sitting on the eggs. Newly hatched young are helpless, but they grow quickly on the food their parents bring.


HERONS, EGRETS, BITTERNS, AND PEOPLE

Large colonies of herons and egrets attract the attention of people. Herons, egrets and bitterns were kept them as pets, and killed for food or their feathers for hat decoration. Herons often take advantage of habitats made by people, such as farm ponds, rice fields, reservoirs, city parks, and roadside ditches.

UMBRELLAS FOR HUNTING

Black herons and many other herons and egrets sometimes stand looking into the water with wings spread in the shape of an umbrella. This casts a shadow over the water. Scientists thought the birds did this because they could see their prey better in the shade than in the glare of sunlight on the water. However birds also do this on cloudy days. Scientists believe the shadow fools fish into thinking they have found a safe place. When fish swim into the shadow of a big bird's "umbrella," the heron quickly snatches a meal.

CONSERVATION STATUS

Some herons, egrets, and bitterns are not threatened, but others are close to extinction, dying out. Many of the birds are in trouble because of wetland pollution and destruction. In some parts of the world they are still hunted for their body parts, or they are killed when they feed at fish farms. Conservation groups are working to save protected areas for these birds and help them make a comeback.

GREAT BLUE HERON (Ardea herodias): SPECIES ACCOUNTS

Physical characteristics: The great blue heron is about 4 feet (1.2 meters) tall. It is the largest heron in North America. It is between 36 and 54 inches (91 and 137 centimeters) long from bill to tail and it weighs from 5 to 8 pounds (2.3 to 3.6 kilograms). Great blue herons come in two colors. The dark heron has mostly gray feathers, and the other one is completely white.


Geographic range: Great blue herons breed in most of the United States, except for mountains and deserts. They also breed in southern Canada and parts of Mexico. During the cold months, some of the birds migrate as far as northern South America.

Habitat: Great blue herons live in many different kinds of habitats, from deep-water lakes to dry land. They can be found in both freshwater and saltwater marshes, mangrove swamps, seashores, meadows, flooded farm fields, and dry pastures.


Diet: Fish, both large and small, are the main food eaten by great blue herons. They also eat other animals, including frogs, small mammals, shrimp and other crustaceans, reptiles, small birds, and insects. They feed mostly by standing still in the water or slowly stalking their prey. However they sometimes dive in and swim after fish and other water animals.


Behavior and reproduction: Great blue herons are noisy birds: they squawk and snap their bills loudly. They nest alone or in small colonies and usually build their stick nests in tall trees near water. Their nests are as large as 39 inches (1 meter) across. Females lay two to seven eggs, but often only one or two chicks survive long enough to fly from the nest.


Great blue herons and people: The great blue heron is the best known heron in North America. Most people are fond of them, except for the owners of fish farms. Great blue herons are the topic of some Native American legends. In one legend, the heron teaches people to stand on their own and have self confidence.


Conservation status: Great blue herons are not threatened. However the population of the all-white great blue herons is getting smaller because of habitat destruction. ∎

CATTLE EGRET (Egretta ibis): SPECIES ACCOUNTS

Physical characteristics: Cattle egrets are white, chicken-sized birds with shorter legs and beaks than most herons and egrets have. They are 18 to 22 inches (46 to 56 centimeters) long from beak to tail and weigh between 12 and 14 ounces (340 and 390 grams). During breeding season, they grow light orange feathers on their heads, backs, and breasts.


Geographic range: Originally they lived only in Africa, Asia, and Australia, but they crossed the Atlantic Ocean to South America and started to spread. In the middle of the twentieth century, they reached North America. Cattle egrets are in all but the coldest areas of North and South America, in addition to Africa, Asia, and Australia.


Habitat: Cattle egrets are more likely to be found in grasslands and farm fields than most herons and egrets. They also live at dumps, on golf courses and athletic fields, rice fields, and lawns. Sometimes they nest with other kinds of wading birds, usually on islands.

Diet: Cattle egrets eat mainly insects, especially locusts, grasshoppers, and crickets. They also catch flies, beetles, caterpillars, dragonflies, mayflies, cicadas, spiders, and frogs.


Behavior and reproduction: Cattle egrets often walk near cattle and other hoofed animals, and sometimes they even sit on them. The cattle stir up insects as they walk along, making it easy for the egrets to catch them. Cattle egrets nest in big colonies of a few hundred birds to several thousand pairs. Their stick nests are about 16 inches (40 centimeters) wide. The female usually lays four or five eggs. The chicks leave the nest two weeks after hatching, but they climb around the branches for another two weeks before they fly off.


Cattle egrets and people: Farmers are usually happy to have these insect-eating birds around. But when the birds form huge colonies near towns, some people consider them a nuisance. While trying to control the number of cattle egrets, people sometimes harm less plentiful herons and egrets that are with the cattle egrets.


Conservation status: Cattle egrets are not threatened. The cattle egret is one of the most common egrets or herons in the world. ∎

EURASIAN BITTERN (Botaurus stellaris): SPECIES ACCOUNTS

Physical characteristics: The Eurasian bittern is a thick-necked, medium-sized, golden brown wading bird. It has black feathers on its head and a black "moustache." These bitterns are between 25 and 31 inches (64 and 80 centimeters) long from beak to tail, and they weigh from 1.9 to 4.3 pounds (0.9 to 1.9 kilograms). The feathers on their backs are speckled, which helps them hide among the plants.


Geographic range: Eurasian bitterns live in Europe, Asia, and Africa.


Habitat: They breed among dense, close together, plants in shallow water. During the rest of the year, they spread out to other wet areas, including ponds, ditches, and rice fields.


Diet: Eurasian bitterns eat fish, frogs, insects, small mammals, small birds, and snakes. They hunt by walking slowly among the plants, lifting their feet high with every step.

Behavior and reproduction: When a Eurasian bittern spots a predator, it can "freeze" for hours, with its beak pointing upward and eyes pointing forward. It sways like a blade of grass, making it camouflaged (KAM-uh-flajd) among the plants. It defends its breeding and nesting area by making loud, booming noises and fighting on the ground and in the air. A male bittern may have as many as five mates within his territory. Each female usually lays four or five eggs and the young leave the nest two weeks after hatching. They can fly by the time they are fifty-five days old.


Eurasian bitterns and people: As a result of the bittern's booming call, when it appears in folk tales and legends, it is usually wicked or it brings bad luck.


Conservation status: The Eurasian bittern used to be widespread and abundant, but now it is listed as Vulnerable, facing a high risk of extinction in the wild in the medium-term future, in many areas. ∎


FOR MORE INFORMATION

Books:

Arnosky, Jim Watching Water Birds. Washington, DC: National Geographic, 2002.

del Hoyo, Josep, A. Elliott, and J. Sargatal, eds. Handbook of the Birds of the World. Vol. 1, Ostrich to Ducks. Barcelona: Lynx Edicions, 1992.

Eckert, Allan W. The Wading Birds of North America. Garden City, NY: Doubleday & Company, 1981.

Erlich, Paul R., David S. Dobkin, and Darryl Wheye. The Birder's Handbook. New York: Simon & Schuster, 1988.

Hancock, James and Hugh Elliott. The Herons of the World. New York: Harper & Row, 1978.

Kaufman, Kenn. Lives of North American Birds. Boston: Houghton Mifflin Company, 1996

Perrins, Christopher, ed. Firefly Encyclopedia of Birds. Buffalo, NY: Firefly Books, 2003.

Williams, Winston. Waterbirds of the Northeast. Tampa, FL: World Publications, 1989.

Periodicals:

Allen, Willam H. Jr. "Travels of the Cattle Egret." Grit (October 13, 2002): 18–19.

Berger, Joseph. "In City Bustle, Herons, Egrets and Ibises Find a Sanctuary." The New York Times (December 4, 2003): B1.

Butler, Robert W. "Great Blue Heron, The Birds of North America, No. 24." The Academy of Natural Sciences, The American Ornithologists' Union (1992): 1–18.

Hemingway, John. "An African Bird Makes its Move Around the World." Smithsonian (May 1987): 60–69.

Horton, Tom. "Great Blues are Going Great Guns." Smithsonian (April 1999): 130.

Kerlinger, Paul. "Out of the Blue: Forced South by Snow and Ice, Great Blue Herons in Winter are Adaptable and Unstudied." Birder's World (December 2002): 86–89.

Miller, Claire. "Big Blues." Ranger Rick (June 1992): 20–26.

National Audubon Society. "A Great Blue Heron Rookery in Weathersfield Has Been Restored." Audubon (March 2003): 119.

Runtz, Michael. "The Great Blue Yonder." Nature Canada (Autumn 1999): 28–30.

Telfair, Raymond C. II. "Cattle Egret, The Birds of North America, No. 113." The Academy of Natural Sciences, The American Ornithologists' Union (1994): 1–28.


Web sites:

"Bitterns." Earthlife.net. http://www.earthlife.net/birds/bitterns.html (accessed on April 24, 2004)

"Cattle Egret." New Hampshire Public Television. http://www.nhptv.org/natureworks/cattleegret.htm (accessed on April 24, 2004)

Chesapeake Bay Field Office. "Great Blue Heron." U.S. Fish and Wildlife Service. http://www.fws.gov/r5cbfo/heron.htm (accessed on April 24, 2004)

"Great Blue Heron." Cornell Laboratory of Ornithology. http://birds.cornell.edu/bow/gbheron/ (accessed on April 24, 2004)

"Great Blue Heron Page." NatureWildlife.com. http://www.naturewildlife.com/blueh.html (accessed on April 24, 2004)

Ivory, Alicia. "Bubulcus ibis (Cattle Egret)" Animal Diversity Web. http://animaldiversity.ummz.umich.edu/site/accounts/information/Bubulcus_ibis.html (accessed on April 24, 2004

Naumann, Robert. "Ardea herodia (Great Blue Heron)." Animal Diversity Web. http://animaldiversity.ummz.umich.edu/site/accounts/information/Ardea_herodias.html (accessed on April 24, 2004)

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Herons and Bitterns: Ardeidae

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