Dry then wet: Everglades birds are in for weak season

PALM BEACH, Fla. (AP) — Before a surveillance flight to count wading birds around water conservation areas south of Palm Beach, ecologist Mark Cook was hoping to see signs that recent rains in South Florida had replenished the parched marshes, helping to revive shallow pools packed with fish the birds rely on right now to feed their young.

But what the scientist saw on Friday (May 22) left him worried. It rained too much, too soon. After exceptionally dry conditions in winter and spring, too much water at the start of the rainy season could be bad news for the birds.

“All the rain we had filled up the Glades a lot more than I had hoped for,” said Cook, the lead scientist for the Everglades systems assessment section of The South Florida Water Management District. “If birds get too much water too soon, they will abandon their nestlings.”

There are still thousands of birds nesting in the Everglades, from roseate spoonbills, the pink-plumed birds that were hunted to near extinction for their feathers a century ago, to threatened wood storks, which almost disappeared in the early 1980s. They need the right balance of wet and dry soil to breed and successfully fledge their nestlings.

Last week, Tropical Storm Arthur formed off the Florida coast, its tail end pounding the region with heavy rainfall and gusty winds even before the hurricane season’s official start on June 1.

Wading birds are a key indicator of overall Everglades health, and water managers closely monitor their nesting activity every year.

They’ve had a hard time this year. The wet season last year was weak, which didn’t help the Everglades produce enough fish before breeding season started in November. At that point, the marshes where storks, spoonbills and blue herons like to build their nests were only 40% wet, too dry for prey to become abundant enough to support significant population growth.

Then, the fragile ecosystem saw very little rain in the winter months, with the unseasonably dry season culminating in a record-dry March that dried off canals and scorched foraging habitats for the birds. March this year was the hottest on record for Florida, with an average of just 0.24 inches of rain — the driest in 89 years, according to the Water Management District. The result was that many of the areas where birds traditionally found shallow pools packed with fish disappeared.

“I barely saw any foraging birds at all,” Cook said.

There was more bad news during the 3.5-hour flight over four large water conservation areas southeast of Lake Okeechobee: from between 400 and 450 wood storks that were nesting in those areas, only about 60 were still visible during the surveillance flight.

Nesting may have failed because the wood storks started very late this season, and didn’t have enough food during the dry months. Cook said he was hoping that enough water would have lasted through the dry season, but that didn’t happen.

When wetlands dry completely, the small fish are forced into refuges where they’re often consumed by large fish, alligators, or other predators, or simply dry out. Without consistent access to prey during the breeding season, wood storks can’t feed.

Unlike the storks, the white ibises tend to use larger areas in the Everglades to forage in, and have done better this season. Cook said he saw thousands of white ibises, many still nesting.

This species will likely build on the success of the stellar 2018 nesting season, when wading birds made more nests than any other year in the past eight decades. The record-breaking nesting event was only possible because of the right balance of wet and dry conditions in the delicate ecosystem.

More than 122,000 wading bird nests were counted in the Everglades during the 2018 nesting season, which ranged from December 2017 to July 2018. Overall in South Florida more than 140,000 nests were found, the most since counting began in 1995, compared with an average of about 40,000 a year in the past decade.

Still, the Everglades’s low-nutrient, unproductive environment is a challenge for the leggy birds. Fish grow slowly, and if the heavily-altered system doesn’t get enough water at the right places at the right time, chances are birds won’t survive.

Environmentalists and wading bird lovers are hoping that Everglades restoration projects that seek to replicate some of the natural conditions found before the ecosystem was drained by canals and levees will help the birds. If water conditions are more balanced all year round, wading birds won’t be so vulnerable to the whims of the weather, they say.

Too much water is bad, too, because it disperses prey. That’s Cook’s biggest fear now, as weather forecasts are calling for a wet rainy season, with chances of active storm and hurricane activity. Nesting season runs from about December to July and depends on the species.