Suprise Finding: Wading Birds Thrive After Droughts

Feb. 14 -- Peter Frederick knows better than most of us that sometimes the facts just defy common sense.

It took years for him to accept his own findings, because the evidence he collected as he groped his way through the Everglades suggested something that, at first blush, doesn't make any sense at all. Astonishingly, the evidence indicates the prolonged droughts that periodically threaten the wildlife in that remarkable part of Florida actually cause the population of wading birds to soar.

To Frederick, a wading bird expert at the University of Florida's Institute of Food and Agricultural Sciences, that seemed very unlikely.

The white ibis, wood storks, snowy egrets and tricolor herons depend on the marshy wetlands for the small fish they eat and the tall grasses that hide them from predators. In a dry year, much of that disappears, so it only seems logical that the birds would go elsewhere to breed, or not breed at all.

Surprise Appearances

So no wonder he had trouble believing his own findings when he began his current research more than 13 years ago. A severe drought had gripped the Everglades, and it lasted until 1992.

"It was the most severe drought ever recorded there," says Frederick. "Over 90 percent of the gator holes had dried out," so there was no water in the depressions left in the soft soil by sleeping alligators. And there was little water elsewhere in the area, depriving the birds of many of the resources they need for survival.

So of course Frederick didn't expect to find many nesting birds when the drought finally came to an end.

"We had predicted no nesting, except maybe for a few foolish birds, and we were pretty confident of that," says Frederick, who teamed up with John Ogden, a biologist at the South Florida Water Management District.

But he admits today he and Ogden were caught with their "pants down."

There were birds everywhere. Where they had expected to find no members of some species, they found up to 30,000 nesting pairs.