Wood Stork

Mycteria americana

(c) Jim Fenton
  • CICONIIDAE
  • Storks
  • Ciconiiformes
  • Cigüeña americana
  • Tantale d'amérique
Introduction
The striking, long-legged Wood Stork lives in colonies in cypress and mangrove swamps in the southeastern United States. It frequently flies in flocks, alternately flapping and gliding, or soaring on thermals to great altitudes. North America's only native stork, it is sometimes called "ironhead" or "flinthead" for its featherless, dark-skinned head.
(c) Arnold Dubin
Appearance Description

Wood Storks measure three feet in length, weigh over five pounds and have a wingspan of five feet. They fly with their long necks and legs extended. Their plumage is white except for the short tail and primary and secondary flight feathers, which are black with an iridescent sheen. The unfeathered head and upper neck are covered with rough, scaly, dark gray skin. The long bill is stout, curving slightly downward at the end. Males are larger than females, but the sexes are otherwise alike. Immature birds are grayish, with dusky head feathers and yellowish bills.

Range Map
Courtesy Kenn Kaufman
Range Map Legend
Range Distribution
In the United States, Wood Storks can be found year-round in Florida, Georgia, and South Carolina. Elsewhere in the Western Hemisphere, the birds breed from Mexico to northern Argentina, and in the Caribbean islands of Cuba and Hispaniola. After nesting, some move into Texas, Louisiana, Mississippi, Alabama, and North Carolina, mainly along coastlines and large rivers. In the summer, flocks from western Mexico may appear in southern California and the American Southwest.
 
A legend for the range map to the right can be found here.
 
Habitat

Wood Storks use a mosaic of freshwater and brackish wetlands for feeding, nesting, and roosting. Seasonal and annual differences in rainfall and surface water often cause the birds to switch habitats. They forage in freshwater marshes, tidal creeks and pools, stock ponds, managed impoundments, and seasonally flooded roadside or agricultural ditches. The birds nest primarily in cypress, but also in mangrove trees.

Feeding
Wood Storks often feed in groups, constantly moving through open shallow wetlands where their fish prey is highly concentrated. They primarily consume saltwater and brackish fish species less than ten inches long, especially sunfish. On occasion, they also eat amphibians, crustaceans, reptiles, mammals, arthropods, and other birds. Sometimes, Wood Storks stir the water with their feet in an attempt to startle hiding prey. Feeding birds wade through the water, their heavy bills immersed and partially open. Upon contacting a fish, the mandibles quickly snap shut, and the bird raises its head and swallows the food—a technique called "grope feeding" or "tactilocation."
Reproduction
Wood Storks nest in colonies ranging from a few to thousands of pairs. Seasonally monogamous, they begin breeding at three or four years of age. During courtship, adults have under-wings of pale salmon, long fluffy feathers under their tails, and vivid pink toes. Mating follows a period of ritualized courtship displays. In Florida, Wood Storks lay eggs from October through June. Storks in Georgia and South Carolina lay eggs from March through May. Nests—ranging from three feet high in mangrove colonies to 100 feet high in cypress trees—are constructed of sticks, vines, leaves, and Spanish moss. Wood Storks also nest successfully in artificial structures. Females typically lay one clutch of two to five eggs, but may re-lay after nest failure. Both parents incubate for about 30 days, and both regurgitate whole fish to feed their offspring. The young leave the nest after nine weeks, but are fed for another three to four weeks.
Migration

Not considered true migrants, Wood Storks move in response to the availability of food. When food is scarce, the birds relocate to areas of greater abundance. After breeding, the birds occasionally disperse as far north as North Carolina and as far west as Mississippi and Alabama. Storks sighted in Arkansas, Louisiana, Texas, and points west may originate from Mexico. The lack of thermals needed to cover long distances may restrict the storks from moving between Caribbean islands, where they are thought to be permanent residents.

  • Unknown
  • 58,500
  • Endangered
  • Moderate population declines
Population Status Trends
During the 20th century, southern Florida's Everglades and Big Cypress populations shrank significantly due to habitat destruction and disruption of water flow; rookeries in Texas, Alabama, and Louisiana were also abandoned. However, populations in northern Florida, Georgia, and South Carolina grew. Nesting in Georgia was first recorded in 1976, and in South Carolina in 1981. This northern shift in the bird's breeding range may have partially offset declines at traditional colony sites. The Partners in Flight Bird Conservation Plan for the South Atlantic Coastal Plain lists the Wood Stork among its highest priority species.
Conservation Issues
Many Wood Stork nesting and feeding habitats have been destroyed by development and agricultural expansion, and water management practices that have disrupted natural flooding and drought cycles. Wood Stork nesting grounds must remain inundated during nesting season to prevent predation and abandonment. In addition, the birds require alternate periods of flooding, when fish populations multiply, and dryness, when shrinking pools concentrate the prey at higher densities. Increased manipulation of water levels in southern Florida via canals, levees, gates, and water storage has negatively impacted the storks. Other threats include raccoon predation, the failure of nest trees to regenerate, and human disturbance of stork rookeries.
 

However, Wood Storks can adapt to certain human-caused changes; they sometimes move to more suitable habitats when historic colonies are no longer viable. Others alter their behavior to meet the limitations of new environments—for instance, by nesting in smaller colonies, and feeding individually rather than in groups. The birds also use human-made or enhanced wetland sites for feeding and nesting. At Audubon's Silver Bluff Plantation Sanctuary in South Carolina, flocks of Wood Storks are drawn to artificial feeding ponds created specifically for them. The birds also nest successfully on artificial platforms erected at Georgia's Harris Neck National Wildlife Refuge. In coastal South Carolina, where water impoundments are managed for waterfowl, the storks are often attracted during "drawdowns."

What You Can Do
Support Audubon Florida's Everglades Campaign.
 
For other actions you can take, including Audubon activities, please visit our resources page.
More Information
Visit our resources page for more information about this species.
Natural History References
Coulter, M. C., J. A. Rodgers, J. C. Ogden, and F. C. Depkin. 1999. Wood Stork (Mycteria americana). In The Birds of North America, No. 25 (A. Poole, P. Stettenheim, and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, DC: The American Ornithologists' Union.
 
Hunter, W.C., L. Peoples, and J. Collazo. 2001. Partners in Flight South Atlantic Coastal Plains Conservation Plan, U.S. Fish and Wildlife Service, Atlanta, Georgia.
 
Kaufman, Kenn. Lives of North American Birds, Houghton Mifflin Company, New York, 1996.
 
Sibley, David Allen. The Sibley Guide to Birds. Alfred A. Knopf, New York, 2000.
 
U.S. Fish and Wildlife Service. 1996. Revised recovery plan for the U.S. breeding population of the wood stork. U.S. Fish and Wildlife Service. Atlanta, Georgia.
Conservation Status References
Coulter, M. C., J. A. Rodgers, J. C. Ogden, and F. C. Depkin. 1999. Wood Stork (Mycteria americana). In The Birds of North America, No. 25 (A. Poole, P. Stettenheim, and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, DC: The American Ornithologists' Union.
 
Kaufman, Kenn. Lives of North American Birds, Houghton Mifflin Company, New York, 1996.
 
Sibley, David Allen. The Sibley Guide to Birds. Alfred A. Knopf, New York, 2000.
 
U.S. Fish and Wildlife Service. 1996. Revised recovery plan for the U.S. breeding population of the wood stork. U.S. Fish and Wildlife Service. Atlanta, Georgia.