Wood storks, little blue herons and other nesting wading birds used to measure the health of the Everglades nested in far few numbers over the last year, according to an annual count by the South Florida Water Management District.
While nesting by plentiful white ibises — as likely to be seen on lawns as in marshes — was up 64 percent, rarer birds that rely on specific conditions fell dramatically.
Wood stork nests declined 36 percent, snowy egret nests were down 51 percent, and little blue heron nests fell by 70 percent in 2015.
That should serve as a warning, environmentalists say, of the Everglades’ failing health and the need to speed up restoration efforts.
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Their survival depends on how fast we can build and operate projects.
Audubon Florida Everglades policy associate Tabitha Cale
“Their survival depends on how fast we can build and operate projects,” Tabitha Cale, Audubon Florida’s Everglades policy associate, said in a statement.
South Florida water managers took a rosier view of the numbers, declaring the year a moderate improvement with the boost from ibis nesting, which has increased nationwide since the 1960s. The birds produced about 64 percent more nests than the five-year average and 32 percent more than a 10-year average.
Tricolored heron nesting was also up compared to recent years with more nests counted in Florida Bay, according to the South Florida Water Management District report. The number of nests for roseate spoonbills was three times higher than last year at 365 nests, but far below historic numbers when upwards of a thousand nests were commonly found in Florida Bay.
70%The decline in little blue heron nests
The district blamed poor nesting on dry conditions and a regional drought that struck before the breeding season. That limited the number of small fish that wood stork and other larger wading birds eat. On the up side, those conditions increased the number of slough crayfish, ibises’ primary food, which likely boosted nesting numbers.
Fluctuations in nesting occur naturally in the Everglades, the district said in a statement. But the “sharp decline” in the snowy egret, tricolored herons and little blue herons remains a mystery.
“The causes of these declines,” the district said in a statement, “have not yet been identified.”
Follow Jenny Staletovich on Twitter @jenstaletovich