State and federal wildlife officials have begun releasing captive-bred grasshopper sparrows into the wilds of Central Florida, despite warnings from the scientist in charge of part of the captive breeding program that they may be spreading a fatal disease among the endangered birds.
The Florida grasshopper sparrow is considered the most endangered bird species in the continental U.S. with fewer than 80 adult birds left in the wild. If it goes extinct in spite of more than $1 million spent to save it in recent years, it would be the first American bird in three decades to disappear.
A joint state and federal news release sent out Thursday said the Florida Fish and Wildlife Conservation Commission and the U.S. Fish and Wildlife Service is releasing some of the captive-bred sparrows at an undisclosed location on public lands in Osceola County as part of "an ongoing effort to reverse a near collapse of the species. "
A loss of habitat was the major reason for the sparrows' initial population drop, but more recently it's been battling a fatal parasite.
The protozoan parasite starts in the sparrows' intestines when they are less than a year old and then invades vascular tissue in the liver, heart, spleen and other organs. Because it's a non-native species, their immune system can't fight it off.
It's so deadly that in 2013, 150 or so grasshopper sparrows still remained in the wild. By 2017, biologists counted just 53 males and 22 females in the wild.
In 2013, federal officials approved launching a captive-breeding program, usually a last-ditch effort at saving a species that's teetering on the brink of extinction.They signed contracts with two organizations, one of them the White Oak Plantation in north Florida. The other, an organization affiliated with Florida International University called the Rare Species Conservatory Foundation, has had some success raising the sparrows in captivity while scientists try to figure out how to deal with the parasite. Some of the captive-bred birds turned out to be infected, raising concerns about them spreading it to other sparrows they might encounter.
In December, the foundation and the Fish and Wildlife Service split over whether it's time to release some of the captive-bred birds back into the wild. Paul Reillo, founding director of the Rare Species Conservatory Foundation, contended that releasing the birds now could risk spreading the fatal parasite among the remaining birds. The federal agency wound up canceling its contract with the foundation.
Now the state and federal agencies are going ahead with the release, saying they believe it's a step that's warranted, despite Reillo's warnings.
"While we recognize that releasing captive animals back into the wild may carry some risk, if we don't add to the wild flock soon, it is very likely this unique little bird will go extinct," said Kipp Frohlich of the state wildlife agency. He said the two agencies "have conducted intensive assessments and we are confident the potential benefits are great and outweigh the risks."
Reillo, on the other hand, said Thursday that the government agencies "have crafted a feel-good, public-relations narrative surrounding the hurried release (of captive birds) into the wild sparrow population during the peak of the breeding season. " He said his foundation "continues to encourage the agencies to reconsider their actions and decisions" based on the latest scientific findings.
Florida grasshopper sparrows are about 5 inches long, with flat heads, short tails and black and gray feathers that help them hide. They are generally heard more than seen, with a call that consists of two or three weak notes followed by an insect-like buzz — hence their name.
The species was first described in 1902 by a U.S. Army surgeon, Maj. Edgar A. Mearns, when its population was widespread across south-central Florida. By the 1970s, so many of the prairies that formed their habitat had been ditched and drained and converted to pastures or sod production that sparrow numbers plummeted.
If the Florida grasshopper sparrow does go extinct, it would be the first bird species in the U.S. to do so since a cousin, the dusky seaside sparrow, disappeared in 1987. The last dusky died at Walt Disney World. An effort to save the dusky with a captive breeding program failed when it turned out the only remaining birds were all males.
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