Florida: “Bringing back the ‘most endangered bird’ in the U.S.”

“Three years after being described as on its last legs, the Florida grasshopper sparrow is soaring again,” writes Craig Pittman (National Geographic), with photography by Joel Sartore.

Ashleigh Blackford has seen her share of dramatic bird releases over the years. She vividly recalls California condors soaring high into the sky and San Clemente loggerhead shrikes fluttering free. The tiny Florida grasshopper sparrow, on the other hand, merely hopped out of an open screen and skittered along the ground, says Blackford, a U.S. Fish and Wildlife Service biologist.

Still, it was a thrilling moment to witness: one of the most endangered birds in the continental U.S.—one that just two years ago seemed doomed to extinction—had begun a remarkable comeback. “It wasn’t visually exciting,” Blackford says, “but it was emotionally exciting.”

No more than five inches long, Florida grasshopper sparrows have flat heads, short tails, and black and gray feathers that camouflage their nests, built in the low shrubs and saw palmetto of the state’s grassy prairies. Their name comes from their call, which consists of two or three weak notes followed by an insect-like buzz.

The Florida grasshopper sparrow (Ammodramus savannarum floridanus) was first described in 1902 by a U.S. Army surgeon, Major Edgar A. Mearns. Back then the birds were widespread across central and South Florida. By the 1970s, though, most of the prairies that form their habitat had been ditched, drained, and converted to pastures or sod production.

By 1986, the sparrow population had plummeted to a mere thousand. By 2013, fewer than 200 of the little songbirds remained. [. . .]

To many, they’re just little brown birds. They’re not especially beautiful or exciting or awe-inspiring. And that is part of the challenge in saving them.

“It’s easy to rally support for the tiger and the gorilla,” says Joel Sartore, who began photographing the species’ slide toward extinction for the National Geographic Photo Ark. “Doing the same for the Florida grasshopper sparrow means you’ve really accomplished something. In terms of degree of difficulty, it’s Mount Everest.”

In a last-ditch effort to save the species, federal officials decided to launch a captive-breeding program. Such programs are often expensive and labor-intensive, and sometimes they do not work. [. . .]

If the Florida grasshopper sparrow goes extinct, it would be the first American bird species to do so since the dusky died out 34 years ago.

A breakthrough

No one had ever tried to breed Florida grasshopper sparrows before. In an attempt to minimize impact on the wild population, biologists decided to launch the recovery program by incubating and hatching eggs taken from nests, rather than bringing in adult birds to breed. “We know it’s going to be hard,” Williams said at the start of the program in 2013. “They’re small birds living in dense vegetation, and they’re secretive by nature.”

To start, biologists practiced on a surrogate species. They spent three years exploring captive breeding and rearing techniques on the eastern grasshopper sparrow, which is not classified as endangered. Only when they felt confident in their skills did they try the real thing.

In 2015, scientists followed male Florida grasshopper sparrows’ buzzy chirps to nests hidden amid central Florida’s prairies and carefully removed only eggs and five nestlings, young birds that likely would have died if left in the wild. They also caught two independent juvenile birds and a pair of adults to serve as parents, who could help the captive-reared birds learn how to behave in the wild. (Read about other creative ways scientists are working to save endangered species.)

The eggs went into incubators at a pair of breeding facilities. One was at the Rare Species Conservatory in Loxahatchee, an organization affiliated with Florida International University, on the state’s Atlantic coast. The other was at the White Oak Conservation Center in northeastern Florida. Despite their experience with the other sparrows, the scientists didn’t get it right immediately. Figuring out the proper temperature, humidity, and other key details for incubation took a year and required the collection of more eggs from the wild.

But on May 9, 2016, the first four captive-bred Florida grasshopper sparrow chicks hatched in the Rare Species Conservancy’s laboratory, an event hailed as a major breakthrough.

The hardest part, Williams said in a recent interview, was the uncertainty. “Five years ago, we didn’t know if we could raise these birds in captivity,” he says. “We didn’t know the right light-and-dark cycle for them. How much or what they needed to be fed, or even will they eat in captivity.”

They also didn’t know if captive-bred birds, once released back into the Florida prairies, would know how to protect themselves from predators such as skunks and snakes. That was what the older birds were for, to teach the younger ones those important survival skills.

But the captive breeding program soon faced a complication: In 2016, a previously undetected intestinal parasite began spreading and killing the birds. The lead scientist with the Rare Species Conservancy, Paul Reillo, worried that releasing the birds would spread the disease to the wild population, but White Oak and government biologists argued that it was worth the risk. The dispute grew so heated that in February 2019, the Fish and Wildlife Service ended its contract with the Rare Species Conservancy and transferred its birds to White Oak.

Meanwhile, the sparrows’ wild population continued to plunge. By 2018, only 80 birds remained in the wild, including just 20 breeding pairs, says Craig Faulhaber, avian conservation coordinator for the Florida Fish and Wildlife Conservation Commission. If this trend continued, “there was a strong possibility for extinction,” he says. [. . .]

For full article, see https://www.nationalgeographic.com/animals/2021/01/captive-breeding-save-florida-grasshopper-sparrows/

[Photo above by Joel Sartore, National Geographic.]

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