Florida pulls Keys' ospreys from endangered animals list as numbers climb statewide

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The Florida Keys' ospreys, the fierce fish hawks whose massive nests dot utility poles, channel markers and nesting platforms up and down the ribbon of islands, will no longer be listed as an imperiled species by the state.

State wildlife officials announced Monday that a rare resident population of the migratory birds in Monroe County had been removed from the list in December after a yearlong review found the number of birds rising statewide. While some have argued the Keys' clan should be classified as their own subspecies, said there's no evidence that the ospreys are genetically distinct. It's still illegal to kill the birds, but the designation means fewer rules for developers.

Conservationists welcomed the reported increase. Three decades ago after a seagrass die-off created a 100-square-mile dead zone across Florida Bay oozing pea-green algae, the population plummeted. But they worry about stripping protections while the bay's health remains fragile following a similar seagrass die-off just three years ago.

"The scary thing is we just had a big seagrass die-off followed by algae blooms. This is the same process that led to the declines of the in the '80s and '90s," said Jerry Lorenz, state research director for Audubon Florida. "So I'm going to remain optimistic, but I'm also going to say let's wait and see."

In 2015, the seagrass die-off blanketed 62 square miles in the bay, triggered by a seasonal drought and compounded by decades of flood control that has choked off the supply of fresh water from the north. Lorenz pointed out that seagrass is recovering faster than it did after the 1980s and early '90s crash, when it took 20 years. Algae blooms have been smaller and more sporadic. Water management has also improved as efforts to restore water flows through Everglades restoration work progresses. But the bay remains vulnerable.

"It's pretty clear we're still in crisis mode," said attorney Jaclyn Lopez, the Florida director for the Center for Biological Diversity. "By removing protections, we're potentially losing resources."

The last time the bay crashed, the birds vanished quickly. Lorenz, who has been monitoring roseate spoonbills and other wading birds in the bay for 30 years, remembers passing a string of nests along a mile-long stretch on his way to visit tiny mangrove islands in the bay where wading birds nest.

"First there were 14 nests, then 12 then nine," he said. "Then there were three, then two and then none."

When they looked into the decline, scientists found birds that fed on the ocean side of the islands fared better than those hunting on the bay side. The ospreys hunt by circling over water, then swooping down to snatch fish with talons that include a reversible fourth claw and toes lined with short spines to better grip fish.

Scientists think that as fish disappeared, the birds became vulnerable. Lorenz said numbers around the Keys have still not rebounded to what they were before they crashed. Florida also provides a major winter home for nesting ospreys, with about 20 percent of the U.S. population outside Alaska nesting in the state.

"Development is only continuing to ramp up in Florida," Lopez added, "so we'll only see continued loss of habitats, more roads and more mortality just by being hit by cars."


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Citation: Florida pulls Keys' ospreys from endangered animals list as numbers climb statewide (2019, January 18) retrieved 24 May 2019 from https://phys.org/news/2019-01-florida-keys-ospreys-endangered-animals.html
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