A wood stork with nesting material. PHOTO CREDIT: RJ WILEY
It was a chilly March morning when Lee Martin loaded his gear on a small plane for his monthly flight over Audubon’s Corkscrew Swamp Sanctuary. The goal: Determine nesting status and count nests of one of the most unique species that calls this region home. With 13,000 acres of cypress forest and an adjacent maze of wetland habitats, Audubon has been protecting nesting wood storks at the Corkscrew colony for more than a century.
As research technician, Martin was anxious to check in on the wood storks, which historically begin nesting in Southwest Florida by the end of December. But as he scanned the trees he didn’t spot any of their signature black and white silhouettes. However, from his vantage point 500 feet above the sanctuary, he saw less standing water in the marsh and swamp than he had just a month ago – a good sign, since storks rely on falling water levels to improve foraging conditions.
The timing of the rise and fall of water is key to wood stork nesting success in South Florida. Receding water levels concentrate wading bird prey. Not enough water is an obvious problem, but too much water disperses fish across the landscape, spreading them out and making it more difficult for birds to find food. Without consistent access to prey throughout the breeding season, wood storks cannot feed and fledge their young.
Over the past 20 years, water levels at the sanctuary have been inconsistent. The research team has determined the changing hydrology is likely due to some combination of an increased demand for water across the watershed, water management activities necessitated by flood control, and changes in plant communities.
In the 2018 nesting season, 250 wood storks nested at the sanctuary. In 2019, only two chicks fledged. According to Martin, the birds must initiate nesting by March or risk their feeding grounds becoming inundated with early summer rains before their chicks successfully fledge.
While wood storks have been seen foraging in the swamp, the March overflight confirmed that wood storks are not nesting at Corkscrew this year.
The wood storks’ battle for survival is heavily dependent on water. By reducing water use in the dry season (winter-spring) and advocating loudly for wetland preservation, residents and visitors can help ensure wood storks continue to find the habitat they need at Corkscrew Swamp Sanctuary.
For more information visit www.Corkscrew.Audubon.org.