By Mary Lundeberg
The only stork that nests in the U.S., the wood stork (Mycteria americana) has specific nesting criteria. These stocky birds stand over 3 feet tall with a 5-foot wingspan. Although gangly on land, they are elegant in the air, gliding high on thermals. Adults are somewhat homely-looking, but their chicks are adorable. The presence of wood storks indicates the health of a wetlands environment. Restoring the Everglades could encourage wood stork nesting to reoccur in South Florida.
Due mostly to water management problems, the number of wood stork nesting pairs in the Everglades plummeted in the past decade. Corkscrew Swamp Sanctuary was once the most productive colony in the nation, with an estimated 100,000 storks, but has experienced severe decline. Storks only nested twice in the 10 years between 2007 and 2017, and in far fewer numbers.
More than 43 square miles of wetlands were lost to agriculture and development between 1996 and 2010 in the Big Cypress Swamp watershed (which includes Corkscrew Swamp Sanctuary). An extensive network of canals and roads brought widespread drainage and fragmentation of wetlands.
For wood storks to be successful in reproduction, they need a wet/dry cycle created by an intense four-month rainy season followed by eight months of drying conditions. Storks capture their prey by swishing their bill through water 6 to 10 inches deep. When their bill touches a small fish, it snaps shut. This happens within 25 milliseconds — one of the fastest reflexes known in nature. Because wood storks are tactile feeders, they require concentrations of prey in shallow water.
Some storks fly as far as 80 miles from their nesting grounds to feeding areas. Each nesting pair requires about 450 pounds of fish for the breeding season.
Storks breed in colonies that often include other wading birds, such as roseate spoonbills, ibis, egrets and herons. They prefer cypress swamps with 1 to 3 feet of water. Flooded trees bring patrolling alligators, which preventpredators such as raccoons and snakes from swimming to the nest trees. Both parents share nesting duties.
Although nesting pairs of wood storks have declined in Florida, overall wood storks are a success story. In June 2014, after 20 years on the endangered species list, storks were down-listed to threatened because the population increased to over 10,000 nesting pairs. Florida wood storks have migrated to Georgia, South Carolina and North Carolina.
In Southeast Florida, a water-reclamation project, Wakodahatchee Wetlands, demonstrates that we can build cypress swamps to promote wetlands for wood storks to breed. Moreover, because 2017 was such a wet summer (thanks in part to Hurricane Irma), fresh water flowing south replenished the shallow wetlands in Audubon’s Corkscrew Swamp Sanctuary and brought 400 nesting pairs of storks back last year. This year, however, nesting in Corkscrew is dismal.
If we can restore hydrology systems to get the water right, we may be able to bring back the thousands of wading birds that once characterized the Everglades and South Florida. In the meantime, smaller numbers of wood storks continue to raise chicks in rookeries on the Peace River and eleswhere.