IBISES AND SPOONBILLS: Threskiornithidae

PHYSICAL CHARACTERISTICS

Ibises and spoonbills are alike in many ways, but their long bills are very different. The ibises' bills are thin and they curve downward. Spoonbills' spoon-shaped bills are flat and wide at the tip. Both ibises and spoonbills are medium to large wading birds, birds that walk through shallow water in search of food. Most of them have bare faces and throats, they have long necks and legs, and many of them have colorful feathers. They range in length from 19 to 43 inches (48 to 110 centimeters) from the tip of their bills to their tails, and they weigh between 1.5 and 5.5 pounds (0.5 and 2.5 kilograms).

GEOGRAPHIC RANGE

Ibises and spoonbills are spread widely across the world where the temperatures are moderate or warm.

HABITAT

Most ibises and spoonbills live in wetlands or in wooded areas near water, but some can be found in dry grasslands and on mountains. They are also attracted to farms and rice fields.

DIET

Spoonbills and ibises usually use their sensitive bills to hunt by touch in shallow water or mud. They eat mostly small fish, water insects, frogs, shrimp, and other small water animals. Some of them also eat carrion, dead animals, and feed at garbage dumps.

BEHAVIOR AND REPRODUCTION

When spoonbills and ibises fly, they stick their necks and legs straight out. They are sociable birds, and they usually feed and roost in large groups. It is not unusual to find them with other species of wading birds, including storks and herons. Many of them also move around with big flocks and they breed in large groups called colonies. The parents share the work of building the nest, sitting on the eggs, and feeding as many as five chicks.

IBISES AND SPOONBILLS, AND PEOPLE

For 5,000 years, ibises have been honored in the religions of some people, while others thought the birds brought bad luck. Ibises were carved on ancient Greek coins, and in the Middle Ages, noblemen ate ibises as a special treat. In the 1800s, some species of ibises and spoonbills were hunted for their beautiful feathers.

SACRED FIGHTERS

At nesting time, male sacred ibises use their bills for more than finding food. They arrive at the breeding area before the females. Then they fight for the best nesting places with their bills, and fly at other males to try to knock them off their perches. When the females arrive, more fighting and chasing takes place, until they choose mates. Sacred ibises build platform nests of sticks and twigs and line them with soft plants. But sticks are often in short supply, so the birds fight over them and steal them from other nests in the colony. Eventually, they settle down and the raise their families.

CONSERVATION STATUS

Many spoonbills and ibises are threatened because their wetlands are being drained and taken over by people for building projects and farms. In some countries, people hunt them, and they are still being harmed by dichloro diphenyl trichloroethane, DDT, an insect poison that causes the birds' eggshells to break easily. The reunion flightless ibis became extinct in 1705, and four other species are listed as Critically Endangered, which means they are facing am extremely high risk of extinction in the wild. Two more species are Endangered, facing a very high risk of extinction in the wild, and several more are close to being threatened.

SACRED IBIS (Threskiornis aethiopicus): SPECIES ACCOUNTS

Physical characteristics: Sacred ibises are medium-sized wading birds that are covered with white body feathers. The rest of the bird is black, including its bill and the scaly skin on its naked neck, head, and long legs. They also have lace-like black feathers on their backs that cover their tails. Sacred ibises are between 25.5 and 35 inches (65 to 90 centimeters) long from bill tip to tail, and they weigh about
3.3 pounds (1.5 kilograms). Males and females look alike, but the males are a little larger than the females.

Geographic range: Most sacred ibises live in the southern two-thirds of the African continent, south of the Sahara desert, and on the western side of the island of Madagascar. Large colonies also once lived in the marshes of southern Iraq, but the marshes were drained and many of the birds disappeared.

Habitat: Sacred ibises are found in coastal lagoons, marshes, damp lowlands, and farmlands. They live in both dry and flooded grasslands and along the muddy shores of lakes and rivers. Sometimes they wander into deserts or feed at garbage dumps and in recently burned areas.

Diet: Groups of sacred ibises often feed in shallow pools where they catch little fish, insects, worms, frogs, shrimp, and other small creatures. They can bury their bills up to their eyes as they probe deeply in the mud. They also peck for insects on dry land and follow swarms of grasshoppers and locusts. They sometimes eat seeds and other plant parts, eggs, nestlings, small mammals, carrion, and garbage.

Behavior and reproduction: Sacred ibises have strong wing beats and fly in lines or in V-formations. They can soar high, but they usually fly low over the water. After breeding inland, they often move to coastal areas during the dry season. They are usually quiet birds, but they make grunting and croaking noises during breeding season. They build stick nests and the females lay three or four eggs. Both parents help to raise the young.

Sacred ibises and people: Drawings from ancient Egypt show Thoth, their god of wisdom and knowledge, as a man with the head of a sacred ibis. The Egyptians painted murals and carved statues of ibises, and they even made mummies of the birds. Unfortunately, the sacred ibises died off from habitat loss in Egypt by the beginning of the nineteenth century.

Conservation status: Sacred ibises are not threatened worldwide, but they are no longer able to live in some of the places where they once lived. ∎

ROSEATE SPOONBILL (Ajaia ajaja): SPECIES ACCOUNTS

Physical characteristics: Roseate spoonbills are one of the most unusual looking wading birds species. They can easily be identified by the bright pink feathers on their wings and legs and their long, flattened bills. They have bare heads and red eyes. Roseate spoonbills are about 31 inches (80 centimeters) long from bill tip to tail, and they weigh about 3.3 pounds (1.5 kilograms).

Geographic range: Roseate spoonbills live in the eastern two-thirds of South America, in Central America, and along both coasts of Mexico. In the United States they breed in Texas, Louisiana, and Florida and they spread out to many places across the country after breeding.

Habitat: Roseate spoonbills usually stay near water, and they prefer to nest on islands. They breed along seacoasts, in estuaries where fresh water and salt water mix, and in mangrove swamps. They also breed inland in freshwater swamps, on islands in rivers and lakes, in marshes, and on wet prairies. They feed in shallow water near their nesting places, and also in canals, ponds, ditches, tidal pools, and wherever else they can find shallow water.

Diet: Small water creatures, including fish, insects, crayfish, and shrimp are the main foods of roseate spoonbills. They usually walk slowly and the swing their bills as they hunt for food. They also dig in the mud or chase after schools of fish.

Behavior and reproduction: Roseate spoonbills usually feed in large groups and roost together at night. At nesting time, they form large colonies and build nests of loosely woven sticks in bushes or trees. The females lay an average of three eggs, and both parents help raise the chicks.

Roseate spoonbills and people: In the 1800s it became popular among some women to use spoonbill wings as fans to cool themselves. Many spoonbills were killed for their feathers. Finally, laws were passed to stop the killing of spoonbills and other wading birds.

Conservation status: Between 1850 to 1920, the population of roseate spoonbills in the United States decreased rapidly until there were only about twenty-five nesting pairs left in the country. Since laws were passed to protect them, the birds are making a good comeback. They are still considered a Species Of Special Concern in the U.S., but they are not listed as endangered anywhere. ∎

FOR MORE INFORMATION

Books:

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

Bildstein, Keith L. White Ibis, Wetland Wanderer. Washington, DC: Smithsonian Institution Press, 1993.

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

Hancock, J. A., J. A. Kushlan, and M. P. Kahl. Storks, Ibises and Spoonbills of the World. London: Academic Press, 1992.

Niemeyer, Lucian. Long-Legged Wading Birds of the North American Wetlands. Harrisburg, PA: Stackpole Books, 1993.

Sibley, David Allen. National Audubon Society: The Sibley Guide to Bird Life & Behavior. New York: Alfred A. Knopf, 2001.

Stuart, Chris and Tilde. Birds of Africa, From Seabirds to Seed-Eaters. Cambridge, MA: The MIT Press, 1999.

Periodicals:

Berger, Cynthia. "You Don't Need a Knife or a Fork when You're a Spoonbill!" Ranger Rick (June 2000): 42–46.

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

"Birds Ask, 'Are We There Yet?'" Current Science (November 21, 2003): 14.

Graham, Frank Jr. "Battery Island." Audubon (March 2004): 108.

Graham, Frank Jr. "A Wing and a Prayer." (Roseate spoonbills) Audubon (July 2001): 87.

Line, Les. "Star Billing." (Roseate spoonbills) National Wildlife (April-May 1999).

McNally, Marcia. "Save the Spoonbill." Earth Island Journal (Summer 1998): 7.

Regis, Necee. "The Shy Beauty of the Everglades." Boston Globe (February 16, 2003): M1.

"Spoonbill Woes." Birder's World (April 2003): 16.

Weihs, Daniel and Gadi Katzir. "Bill Sweeping in the Spoonbill." Animal Behaviour (March 1994): 649–654.

Web sites:

"Fact Sheets: Roseate Spoonbill." National Zoo. http://nationalzoo.si.edu/Animals/Birds/Facts/FactSheets/fact-rosespoonbill.cfm (accessed on May 14, 2004).

"Sacred Ibis." KenyaBirds.org. http://www.kenyabirds.org.uk/sacred.htm (accessed on May 14, 2004).

"Roseate Spoonbill, Ajaia ajaja." U.S. Geological Survey. http://www.mbr-pwrc.usgs.gov/id/framlst/i1830id.html (accessed on May 14, 2004).

"Roseate Spoonbill." Everglades National Park, National Park Service. http://www.nps.gov/ever/eco/spoonbil.htm (accessed on May 14, 2004).

"Scarlet Ibis." National Zoo. http://nationalzoo.si.edu/Animals/Birds/Meet_the_zoos_birds/zoo_bird_info.cfm?bird=Scarlet%20ibis (accessed on May 14, 2004).

Weinstein, Tasha Marie. "The Roseate Spoonbill; At Home in Florida Bay." Florida Bay Education Project. http://www.floridabay.org/pub/newspaper/spoonbill.shtml (accessed on May 14, 2004).

"White Ibis, Eudocimus albus." U.S. Geological Survey. http://www.mbr-pwrc.usgs.gov/id/framlst/i1840id.html (accessed on May 14, 2004).

"The White Ibis." National Audubon Society. http://www.audubon.org/bird/BoA/F37_G1c.html (accessed on May 14, 2004).