What's good for the Everglades isn't always so good for one of its smallest and most threatened inhabitants: the Cape Sable seaside sparrow.
This winter, after record rain and water drained from Lake Okeechobee left conservation land to the north flooded, water managers opened flood gates into Everglades National Park for the first time in decades. Biologists celebrated the chance to see Everglades restoration in action. But the unseasonable rain, which also fell over the park, has made what should have been a good dry-season test run into a complicated balancing act, with water levels in critical sparrow grounds far too high heading into nesting season.
“We knew that was going to happen. It’s kind of a trade off,” said U.S. Fish and Wildlife Everglades Program Supervisor Bob Progulske.
What biologists didn’t anticipate was just how bad conditions would be — the worst Progulske says he’s seen in 30 years.
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We’re very concerned about the outlook for this bird.
U.S. Fish and Wildlife Everglades Program Supervisor Bob Progulske
“We’re very concerned about the outlook for this bird,” he said.
Getting the water in the right place at the right time also shows the extreme difficulty of managing water in an ecosystem where even a few inches matter. The sparrow, which now inhabits six locations in the Everglades, nests in rocky grass prairies that regularly flood. The golfball-sized bird spends much of its life hopping around in grasses until breeding season between April and July, when the birds build nests just six inches off the ground. Water levels need to be high enough to keep nests safe from predators but low enough to keep them from washing away.
Maintaining those levels has meant keeping some flood gates shut, which doesn’t always sit well with hunters who use conservation areas to hunt deer and ducks. They argue high water in the sprawling region is making it tough for other wildlife, including the equally endangered snail kite.
For months, South Florida Water Management District board member Jim Moran has complained about restrictions for water management guided in part by sparrow habitat.
We could move a lot more water into Everglades National Park if it weren’t for the situation with the sparrow.
South Florida Water Management District board member Jim Moran
“We could move a lot more water into Everglades National Park if it weren’t for the situation with the sparrow,” he said at the board’s March meeting. “We need to reassess our priorities and decide if we want to save the bird’s habitat at the expense of the rest of the ecosystem.”
But wildlife managers say managing water isn’t just about saving the birds, which have fallen from about 6,600 in 1981 to just over 3,200 birds last year. Bird habitat helps them understand historic patterns of water flow. They are particularly concerned about a small population on the western edge of the marshes, where half the population once lived, that is under increasing threat.
This winter when waters rose, Progulske’s team insisted that two western gates along the Tamiami Train remain closed to give the nesting grounds a better shot. That left two gates to the east and a new one-mile stretch of bridge open for water to drain. Biologists base their decisions in part on a mapping tool developed by the U.S. Geological Survey that allows them to determine both water and ground levels across marshes, critical data to help determine how much territory is available for the low-nesting birds.
The data provides a real time look at water levels and whether conditions are right for nesting.
One of the biggest surprises is just how critical a couple of centimeters of water can be for the ecology.
U.S. Geological Survey hydrologist Paul Conrads
“One of the biggest surprises is just how critical a couple of centimeters of water can be for the ecology,” said USGS hydrologist Paul Conrads, one of the project’s lead scientists at the agency’s South Atlantic Water Science Center.
Near the western nesting grounds, water remains remarkably high, over three feet deep. Last April when sparrows were nesting, water was at 0.16 feet deep. The number of birds in the area has declined from more than 150 in 1981 to about a dozen. Normally the birds, which take about 45 days to lay, hatch and raise their young, produce two to three clutches a season. This year, Progulske said he’ll be happy to get just one.
When water swelled to dangerous levels in Lake Okeechobee after record rain in February, critics again complained protections for the bird were holding up water and forcing water managers to dump polluted lake water into the St. Lucie and Caloosatchee rivers. The releases left both coasts with muddy black and brown water.
But in a March meeting with the district’s water resources board, U.S. Army Corps of Engineers Lt. Col. Jennifer Reynolds said opening western gates would have hardly any effect on lake levels while potentially devastating sparrow habitat.
“Right now, the condition of the sparrow is so dire that we’re doing everything we can to save even one pair of breeding sparrows and give them an opportunity to have a clutch,” she said. “This is probably going to be the worst breeding season we’ve seen for the sparrow in decades.”
With water resource management, if you get it right, you’ve probably pissed off everybody equally.
U.S. Geological Survey hydrologist Paul Conrads
The Corps is also set to start construction on another span of bridge over the Tamiami Trail, this one stretching about 2.6 miles, which will allow even more water to follow its natural path. But even with more water flowing south, biologists warn not everyone may be happy with the results.
“So much of the challenge of restoration science is between observation in the field and how things are responding,” Conrads said. “With water resource management, if you get it right, you’ve probably pissed off everybody equally.”
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