By JENNIFER SORENTRUE
Palm Beach Post Staff Writer
Thursday, April 02, 2009
South Florida's wading birds are resilient.
After a dismal nesting season last year, scientists have seen a surge in the number of great egrets, white ibises and endangered wood storks breeding in western Palm Beach County marshes and other parts of the Everglades.
The reason: South Florida's drought has created hospitable conditions. Shrinking pools of water in western marshes make it easier for them to find food to feed their young.
Water levels are so ideal in the Arthur R. Marshall Loxahatchee National Wildlife Refuge that even the endangered wood stork is showing its white feathers there. The birds have not been seen nesting in the refuge since 2001. Before that, wood stork nests had not been spotted there since 1990.
"This year it is doubly exciting," said Cindy Fury, a senior biologist at the refuge, which occupies the northernmost remnant of the Everglades. "We are having a good nesting year and we also have wood storks."
But scientists aren't counting the eggs yet.
A heavy string of rains or an extremely dry few weeks could throw the area's delicate water levels out of balance, forcing the birds to abandon their nests and their young.
Too much water causes fish and other prey to disperse, making it harder to catch them. Too little water and there won't be any fish at all.
Water levels are especially crucial for wood storks, Fury said.
They need enough water to stand and dip their beaks to find food. Storks search by moving their beaks back and forth under water. When they feel a fish, they grab it. If the water is too high, they cannot stand up.
In late March, surveyors reported spotting 20 to 30 wood stork nests in one of the refuge's colonies, Fury said.
"It is very promising to see them," she said. Still, "You can't rest on your laurels and say the crisis is over."
Last year, the number of wading bird nests in South Florida fell 51 percent to 18,418, according to a report compiled for the South Florida Water Management District. The number was down almost three-quarters from 68,750 in 2002, the best year on record since the 1940s.
Scientists are hopeful that this year also will be a banner year.
During a March 4 survey, scientists found more than 3,000 nests belonging to great egrets, snowy egrets and white ibises in the refuge. They found just 795 great egret nests there on the same day last year.
Surveyors have seen a similar surge throughout the state-owned Everglades conservation areas between the federally managed refuge and Everglades National Park.
The birds can thank Tropical Storm Fay for this year's favorable water levels, said Dean Powell, director of watershed management for the district.
In October, the storm dumped rain over South Florida. During the winter dry season, the water has gradually receded.
In recent weeks, the water was starting to dry a little too quickly, Powell said. But heavy rains late last month in parts of western Palm Beach County replenished state and federally managed marshes.
"Under certain circumstances, if you get heavy rains and it is too deep for the birds, they will fly away," Powell said. "We were within the threshold where you could see it."
But Fury said she has not found any nests that were abandoned in the refuge as a result of the rain.