Corkscrew Swamp was once the biggest nesting ground for North America’s Wood Storks. In the past 60 years, close to 100,000 baby storks were born in the sanctuary’s moss-drenched cypress forest.
Today, the Audubon preserve, located in Naples, Florida, is lucky to get a fleeting visit from a hundred of the bald-headed birds. In fact, it’s only seen two successful Wood Stork breeding seasons in the last decade. For all the other years, the water levels have been too high or too low for the birds to feed and raise their chicks.
But according to the Naples Daily News, things are looking up this winter. Following balanced wet and dry seasons in southern Florida, Corkscrew is just flooded enough for the once-endangered avians to move in. A recent aerial survey by the sanctuary’s science team (paired with the nonprofit LightHawk) revealed at least 40 to 50 active nests wedged into the stands of bald cypress trees.
Experts from Audubon Florida, however, remain cautiously optimistic. “Wood Storks are considered the ‘Goldilocks’ of wading birds,” Shawn Clem, Corkscrew’s research manager, says.
The species is closely adapted to the complex ebb and flow of the Everglades wetland system. Its primary food sources are freshwater fish and crustaceans (with the odd baby alligator and snake mixed in). When the rains come down hard in June (or January, in last year's case), the fish flourish and reproduce; as the ground dries up over the next few months, they concentrate in the remaining wet zones. This sets up the perfect feeding—and training—opportunity for Wood Storks and their newly fledged young. They rummage through the shallow waters with their ultra-sensitive beaks, hoovering up any prey they touch or see. Chicks learn to forage on their own at about eight weeks.
If water levels don’t drop at a steady pace, there’s a problem: The storks won’t be able to find enough food because the prey won't be concentrated in small areas. According to Clem, the same could happen if it rains too much during the nesting cycle: Just a six-inch rise at Corkscrew might tip the balance. Conditions are expected to stay cool and dry with the current La Niña weather cycle, but Clem warns that conditions in the Everglades are always unpredictable. Ultimately, the success of the stork colony depends on its chicks; if they don’t survive, the season is a wash.
In such cases, it’s possible the birds would pack up and try nesting elsewhere. (Wood Storks have been known to lay a second clutch of eggs after the first one fails.) And with the overall population slowly moving farther north—as far as North Carolina—it’s adapting and finding new places to breed. That’s good for the species as a whole, but the future of the Corkscrew birds still remains shaky. Not only are the storks not returning each year, they’re also breeding later every season. Nests built in January or February are often less productive than ones built a month or two earlier. Again, it comes down to flooding and drying—patterns greatly affected by the changing climate.
As much as Clem wants to see the storks stay, she’s not hoping for a quick fix. “People have asked us about farming fish and creating impoundments [at the sanctuary] in the past, but that’s not our focus.” The Wood Stork, she says, is an indicator for the health of the entire ecosystem. Whatever the best answer is, it needs to be as intricate and complex as the Everglades itself.