Food Ran Out in the Everglades After Heavy Rain Last Year. Wading Birds Had Trouble Nesting

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MIAMI, Fla. — Wading bird nesting — a key indicator of Everglades health — was weak in 2020 after a very wet rainy season started early with massive storms in May, diluting pools where fish had concentrated and flooding nests full of chicks that weren’t able to fly yet.

Most nest counts were well below the 10-year average and just a fraction of the record-breaking 2018 season that produced massive colonies close to numbers seen in the 1930s and 1940s. There were considered highly productive decades for Everglades bird life.

The 2020 wading bird report — compiled by the South Florida Water Management District, Audubon Florida, the University of Florida, Florida Atlantic University and others — estimated there were 43,860 wading bird nests in South Florida, lower than the 10-year average of 46,841 nests and about three times less than in the banner 2018 season, when 138,834 nests were counted. In 2019 about 33,000 nests were registered. The most recent annual survey documented nesting from November 2019 to June 2020.

“Drier than average conditions for most of the nesting season followed by a large rain event in May created unfavorable conditions for nesting,” said Mark Cook, the district’s wading bird expert.

Federally threatened wood storks, which almost disappeared in the early 1980s, abandoned hundreds of nests in May last year after record-breaking rain led water levels to rise by more than one foot in some areas in the Everglades. Great egrets, which started nesting later, also left nests before chicks were able to fledge. Roseate spoonbills and white ibises were bright spots in the report, producing more nests than average and slightly increasing their range.

There were also more nests in coastal areas like Florida Bay, a historic nesting ground that is slowly recovering as more water started to flow south as a result of Everglades restoration projects such as the removal of the old Tamiami Trail. Nearly 25% of all nests were found in coastal areas, compared with as little as 10% about 10 years ago, the report said.

Starting in the 1920s, when flood control projects began drying up the southern Everglades, wading birds started to move north into water conservation areas and around Lake Okeechobee. One of the aims of restoration is to bring birds back to where they historically nested, Cook said.

As a nutrient-poor environment, the Everglades needs to get its delicate water balance right to sustain wading birds: a plentiful but not record-breaking rainy season to produce abundant fish and then a steep drop in water levels at the start of the dry season, which is when nesting kicks off. By then, the fish move into drier, more concentrated pools and birds can successfully nest and feed their young.

But in 2020, a record-dry first quarter didn’t produce enough fish for wading birds in the Everglades, and then suddenly in April and May there was too much rain, spelling trouble for nestlings that needed a few more weeks of dry weather before they could leave their nests.

The extreme weather events happened against a backdrop that’s tricky for wading birds to navigate. Decades of dredging and canal cutting in South Florida turned the Everglades into a compartmentalized mosaic of conservation areas, agriculture fields, cities and a national park, which means the birds can’t rely on the natural high and low water patterns for their survival.

Environmentalists hope 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.

“The science tells us that Everglades restoration works for wading birds,” said Kelly Cox, Audubon Florida’s Director of Everglades Policy. “This report shows that if we remain steadfast in our commitment to Everglades restoration, wading birds will have a greater chance of reaching their historic numbers.”

In the 26th edition of the annual report, wood storks produced only 1,795 nests in 2020, 28% less than the 10-year average of 2,490 nests. Wood storks are more picky about where they nest and forage, and require more time than other species to fledge chicks after they hatch. They need about two months of good water and food conditions for nesting success.

White ibises had almost 22,000 nests, 20% lower than the 10-year average, while great egrets produced 6,893 nests, a 20% decrease compared to the 10-year average of 8,698 nests.

The roseate spoonbills, the pink-plumed birds that were hunted to near extinction for their feathers a century ago, had a better nesting season than most species. The report counted 1,262 nests, an improvement on recent years and more than double the 10-year average of 514 nests.