Storks are large wading birds that live near
swamps, marshes, lakes, and rivers. There are
nineteen species in the world. North America is
home to two species, the wood stork of the southeastern
United States and the jabiru of Mexico.
Manyspecies live in Africa, Asia, and Europe, and
a few species also can be found in South America
and Australia. The white stork is most commonly
known. It summers in Europe, frequently nesting
on rooftops, and is the source of the legends of
storks delivering infants.
Physical Characteristics of Storks
between five and thirteen pounds. The smallest species is the Abdim's stork. The saddlebill and the marabou stork are the largest. Storks have powerful wings and a wide wingspan. The marabou's wingspan is the greatest of all land birds, reaching nearly ten feet. Plumage can be white, gray, or black. Species with dark plumage often have iridescent shades of purple, green, or blue. Males and females look alike, but the male is larger. Storks have long, slender legs that may be red, white, gray, or black. They have three long toes that are webbed at the base, and a shorter back toe. The strong beak is long and pointed and is straight or slightly curved.
Storks are carnivores and hunt for food in wetlands, along bodies of water, and in grassy plains. They feed on insects, worms, fish, frogs, reptiles, and small birds and mammals. The adjutant storks are scavengers, primarily seeking carrion. Many storks are tactile foragers, walking slowly through shallow water, groping with an open bill that snaps shut reflexively when it comes into contact with prey. Others are visual foragers, snatching insects or stirring the water to disturb prey, then seizing it with a thrust of the beak. Storks do not vocalize. Instead, they communicate with bill clattering and snapping, rasping, and hissing. Nestlings make a high-pitched braying which decreases with age. Storks fly with their necks stretched out. The legs dangle during takeoff, and then extend out behind in flight. Storks glide on thermals, soaring to high altitudes. They sometimes perform aerial acrobatics such as diving and flipping. Some stork species migrate seasonally, others are nomadic, and some are nonmigratory. The availability of prey largely determines the migration and movement of stork colonies. Prey availability is in turn closely tied to climate and rainfall patterns. Storks will adapt the timing of migration and breeding and the choice of colony nesting site according to these climatic conditions, postponing or skipping a breeding cycle if food availability is low. Excepting one or two species, storks live in colonies, building their nests of sticks, reeds, and vines in trees, on rooftops, or on the ground. Some mate for life; others may pair for just one season. Courtship begins with a color change of the birds' bill, face, legs, and skin. The male performs various aggressive, ritualized displays to attract the female, who then performs appeasement displays. Both members of the pair participate in nest building, incubation, and caring for nestlings. Clutch size is two to five eggs, and incubation averages thirty days. Parents feed the young by regurgitating food into the nest. The fledgling period varies from six weeks to four months.
Since 1950, the overall population of storks has declined by half, due to the destruction of wetland habitats from deforestation, drainage, farming and pesticide use. In 2000, the Storm's stork, greater adjutant, and oriental wood stork were listed as endangered by the International Union for Conservation of Nature and Natural Resources. The lesser adjutant, milky stork, black-necked stork, painted stork, and wood stork are considered vulnerable or near threatened. In the United States, the wood stork serves as an indicator species for the health of the Florida Everglades ecosystem. Solutions to the declining world stork populations include habitat improvement and protection, captive breeding and reintroduction of species, and artificial establishment of nesting and colony sites.
Order: Ciconiiformes (wading birds)
Suborder: Ciconiae (storks, ibises, spoonbills)
Family: Ciconiidae (storks)
Genus and species: Ten genera, one subgenus, and twenty-one species, including Mycteria americana (American wood stork), M. cinerea (milky stork), M. ibis (yellow-billed stork), M. leucocephala (painted stork); Anastomus oscitans (Asian open-bill stork); A. lamelligerus (African open-bill stork); Ciconia nigra (black stork), C. abdimii (Abdim's stork), C. episcopus (woolly-necked stork), C stormi (Storm's stork), C. maguari (Maguari stork), C. ciconia (white stork), C. boyciana (oriental white stork); Ephippiorrhyncus asiaticus (black-necked stork), E. senegalensis (saddle-bill stork); Jabiru mycteria (jabiru stork); Leptoptilos javanicus (lesser adjutant stork), L. dubius (greater adjutant stork), L. crumeniferus (marabou stork)
Geographical location: Every continent except Antarctica; most species are found in the Eastern Hemisphere
Habitat: Wetlands; some species require distinct wet and dry seasons
Gestational period: Incubation averages thirty days
Life span: Seven to thirty years, varying by species; longer in captivity
Special anatomy: Long, slender legs; long neck; long, pointed bill
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