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Storks

American Storks



The only stork of North America is the wood stork (Mycteria americana), sometimes called the wood ibis. The wood stork has white body feathers, black flight feathers, gray legs, and a blue-gray featherless head. Its 9-in (23-cm) bill is gray, and it curves downward slightly at the end.



The wood stork lives primarily in the swamps of southern Florida, where it breeds in stands of large bald cypress trees. It also occurs more widely in Central and South America. In Florida, however, many of its nesting trees have been cut down, and wood stork habitat has also been destroyed or damaged by agricultural activities and drainage. In the 1950s, these birds were seriously threatened, until the Corkscrew Swamp Sanctuary was designated to protect a large nesting population. Their population, however, is still seriously depleted.

Wood storks feed primarily on fish, plus small frogs, reptiles, crustaceans, and mollusks. They use their feet and their bill to feel for the presence of food, which they snap up in their beak. They rarely depend on sight when hunting. Some wood storks also feed in open fields, where they hunt for insects in newly turned soil.

Wood storks do not mate so much according to the season, as to the level of water in their swampy habitat. They raise their young during the dry season, when their wetlands concentrate into prey-rich pools. These dense food supplies makes feeding hungry young storks easier. At the proper time, the male selects a nesting site, usually in a large bald cypress. At first, any female approaching the nest is driven away, but eventually he accepts a mate. The female holds the chosen nesting site while the male collects sticks as nest-building material. The female lays 2-5 eggs, but incubation starts as soon as the first one is laid. The eggs hatch after about 30 days of incubation by both birds. The fluffy white young remain in the nest until they are fully feathered, about 55 days after hatching.

The nest can be a dangerous place. Adolescent storks are prone to an activity that has been likened to that of juvenile gangs of humans. Groups of immature storks, younger than the age of three years, will attack nests, trying to drive the parents away. Then they tear apart the nest and kill the young. If this happens, the parents will build another nest and lay more eggs.

The only other American stork resides in tropical wetlands in South America. The jabiru (Jabiru mycteria) is among the largest storks, and can stand as tall as a human. Except for its head and neck, which are black and red, its plumage is white. The wings may span 7 ft (2.2 m) or more. Its 12-in (30-cm)-long bill is also black. The name jabiru is also sometimes given to the saddle-billed stork of Africa.

All large birds are in danger from hunters, and storks have the added problem of losing much of their wetland habitat to development. The presence of white storks on the rooftops of Europe has long been considered good luck. However, the numbers of these famous storks have dropped by about 90% in the last hundred years. Several changes explain this loss, including the effects of pesticides, loss of nesting and foraging habitat, changing climatic conditions, hunting, and the intensification of agricultural management (which degrades foraging habitat of the storks). Most species of storks are threatened by similar environmental changes associated with human activities.


Resources

Books

Sibley, David Allen. The Sibley Guide to Birds. New York: Knopf, 2000.


Jean F. Blashfield

Additional topics

Science EncyclopediaScience & Philosophy: Stomium to SwiftsStorks - American storks