Weak wet season spells trouble for wading bird breeding in the Everglades
It’s been a weak wet season in South Florida and water managers are worried there may not be enough fish to feed wading birds as breeding season approaches.
The Everglades marshes where wood storks, roseate spoonbills and blue herons like to breed and build their nests are only 40 percent wet at this point, too dry for prey to become abundant enough to support significant population growth, said Lawrence Glenn, director of the water resources division at the South Florida Water Management District.
“This year probably won’t be the best year for wading birds,” Glenn said Thursday at the district board’s monthly meeting. He said what’s important is to have wet conditions before the start of nesting season, which usually starts in December or early January. Plentiful rain is necessary to improve the habitat of the prey that wading birds need to feed on before they breed and while they are nesting, Glenn explained.
“When there is more rain and more water in the marshes during the wet season, we typically see higher nest counts during the dry season that follows,” he said.
Last year, wading birds in the Everglades built more nests than in any other year in the last eight decades, a record-breaking nesting event that was made possible by the right balance of wet and dry conditions at the right time 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 last year. 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.
The boom followed South Florida’s wettest rainy season in more than 80 years, from record-breaking downpours in June to Hurricane Irma in September. Flooding damaged homes and property, but the unusually wet summer and destructive storms had a silver lining: They recharged the Everglades’ shallow wetlands, reproducing historical habitat conditions that were healthy enough to support an explosion of wading birds.
The unusually wet rainy season boosted fish and crayfish production over large areas of the Everglades, especially in higher elevation marshes like Big Cypress Basin. Typically, the area is too dry to produce all the prey that’s necessary for the birds to flourish.
Wading birds are a key indicator of overall Everglades health. From the 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, water managers closely monitor their nesting activities every year.
In 2018, a super colony of 60,000 birds nesting in tree islands in a conservation area just north of Alligator Alley was celebrated after water managers were able to keep tree islands surrounded by enough water to keep predators away so that birds could nest in peace.
Glenn said that event is unlikely to happen this year because the area is just too dry going into the dry season.
Earlier this month the Army Corps of Engineers said that water levels at Lake Okeechobee — the liquid heart of the Central Everglades — were getting too low as a weak wet season left South Florida’s inland sea around levels seen in 2011, when the state experienced the worst drought in nearly a century.
Lake O rose just about an inch in October, after the driest September on record, and on Nov. 1 was at 13.45 feet. Lake levels dropped to 13.27 by Thursday, according to the district.
This story was originally published November 15, 2019 at 7:47 AM.
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