From Florida Keys, Bleak Word on State of Once-Abundant Bird Life

George Powell shushes his excited fellow passengers in the small boat off a tiny, mangrove-lined island in Florida Bay.

“If you’re quiet, we can hear the babies begging for food,” he whispers.

Sure enough, there is a high-pitched, whining sound. Through binoculars, the reddish-pink baby birds can be seen reaching into their parents’ throats for a meal.

Although viewing the nests of the roseate spoonbill, found only here and on the Texas coast, is a treat for some of the out-of-town National Audubon Society members along on this afternoon, there’s more than bird-watching going on.

“It’s no longer sufficient for bird people to be bird people,” says Powell, a bearded, lanky ecologist who’s been based in the Florida Keys for eight years. “We’re going far afield from the traditional binoculars and note pads.”

The society’s field research office in nearby Tavernier just marked its 50th anniversary. In that time, National Audubon researchers have recorded steep declines in bird populations.

Where huge colonies of wading birds were once common, the numbers of wood storks, ibis, spoonbills and herons are down by more than 90% in some cases. Where there were 200,000 white ibis counted in the 1930s, their number was down to 25,000 in 1972 and about 5,000 now, researchers estimate.

The decline in the Everglades system’s birds should serve as a warning to the humans who have crowded into South Florida, claiming wildlife habitats for condominiums, researchers say.

“People say: ‘So, there are fewer birds,’ ” says Peter Berle, president of National Audubon. “But linking of that to the system, to the overall ecological health, shows that the system is sick.”

Sandy Sprunt, director of Audubon’s field research unit, says: “When you start knocking little pieces out of a system, the whole system begins to deteriorate. Sooner or later, the whole thing goes down the drain.”

Based on Florida Bay, the researchers are at the end of what’s now recognized as a vast ecosystem that begins at the top of the Kissimmee River, near Orlando, stretches through giant Lake Okeechobee, and down the Everglades. Belatedly, alterations to the system--draining and diking it, urbanization--are being recognized as damaging not only to wildlife, but to water supplies that support the urban populace.

“People are learning that you can’t bulldoze part of it and expect the rest to be all right,” Berle says. “The system is much more complex.”

His organization, which has 600,000 members, is expanding its scientific mission.

To study birds, you must study the world around them, Powell says. Birds eat fish, so you study fish too. And fish eat sea grass, so you study sea grass. And you watch for the effects of the nutrients flowing here from the urban discharges or of too much or too little water pumped into the bay, depending upon the human needs to the north, the researchers say.

Powell monitors the birds’ reproductive success, a strong barometer of environmental health, he says.

Researcher Thomas Bancroft, in a joint project with state and federal agencies, tracks wading bird populations by plane. Researcher Wayne Hoffman studies seed-eating birds’ droppings to monitor the role birds play in maintaining plant diversity in the tropical hammocks. Mike Ross’ research is on effects of changes in water conditions on the land-based ecology.

They have put radio transmitters on some birds, and found birds ranging dozens of miles from their original home areas in frustrating efforts to find permanent nesting sites where there will be a constant food supply. The birds’ range is limited, meaning many babies are left starving because their parents can’t get back to the nests with enough food, the researchers say.

White-crowned pigeons have become a threatened species mainly because homeowners in the Keys have destroyed the poisonwood trees in their yards, the researchers believe. Poisonwood causes toxic rashes in humans, but it is a major food source for the pigeons.

It’s early evening, and the boats drop anchor for the sunset on Florida Bay. Sprunt hands out drinks and talks about the changes he has seen since coming to the Keys in 1957.

The population, which numbered about 15,000 people north of Key West in the Keys, has more than quadrupled. Tropical hammocks have given way to shopping centers. Florida Bay used to be a fishing paradise, hosting a fishery and supporting at least 15 families who caught trout on simple hook-and-line operations, Sprunt recalls.

“You couldn’t catch that many trout today if you were going to get shot tomorrow,” he says.

The spoonbills, their colorful plumes in demand in the 1930s for ladies hats, were near extinction when the Audubon Society opened its field office here. The population slowly built back up, reaching 800 breeding pairs in the 1970s, Sprunt says.

But now, they’re down to 600 pairs and are in “a precarious position,” Sprunt says. They’ve been shifting nesting areas as food supplies--small fish and shrimp--have been decimated by development.

“Ultimately, we’re on an artificial system. The (drinking) water comes from the mainland. The Keys are finite, you just don’t have the room,” Sprunt says. “Something’s going to give.”