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.

By Craig Pittman
Published 28 Jan 2021, 10:46 GMT
At the end of the 2020 breeding season in August, researchers counted some 112 Florida grasshopper ...

At the end of the 2020 breeding season in August, researchers counted some 112 Florida grasshopper sparrows in the wild.

Photograph by Joel Sartore, National Geographic Photo Ark

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 grey 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.

“This is an emergency, and the situation for this species is dire,” Larry Williams, head of the South Florida office of the Fish and Wildlife Service in Vero Beach, said at the time. “This is literally a race against time.”

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.

Photograph by Joel Sartore, Nat Geo Image Collection

“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 labour-intensive, and sometimes they do not work. (Amidst hybridisation and habitat disruption, the ‘Highland tiger’ is clinging on by a claw.)

In the 1980s, something similar happened with a relative of the Florida grasshopper sparrow, a bird called the dusky seaside sparrow. By the time federal officials decided to go ahead with captive breeding, there were only five duskies left—all of them male. The last one died in captivity at Walt Disney World in 1987.

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 minimise 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 organisation affiliated with Florida International University, on the state’s Atlantic coast. The other was at the White Oak Conservation Centre 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.

State and federal agency officials consulted with biologists from the National Audubon Society and the Archbold Biological Station in central Florida. Ultimately, they concluded the risk of seeing the parasite spread through the wild population wasn’t as dangerous as the risk of seeing the wild population spiral toward oblivion, Williams says.

They began releasing the captive-bred birds in May 2019.

The family of Subway co-founder Fred DeLuca donated 27,000 acres of undeveloped near Yeehaw Junction, in Osceola County, for preservation. It contains about half of all Florida grasshopper sparrow breeding pairs.

Photograph by Carlton Ward

Into the wild

Since then, some 250 captive-bred grasshopper sparrows have been set free in Florida, released every few weeks, even through the pandemic. (Follow Nat Geo’s coronavirus coverage here.)

The coronavirus did not hamper their work. The biologists minimised the number of people in the field at any one time and wore masks while transferring the birds, says Ken Warren, spokesperson for the federal agency.

The release routine went like this: State and federal biologists would pick up the captive birds from White Oak and do a final health check on each one. Then they would place the birds into specially designed crates, Faulhaber says, and drive them four hours south to a release site. (The locations are kept confidential because some are on private lands.)

The birds then went into a screened aviary, about 60 feet by 20 feet, where they’d get mealworms, water, and a couple hours’ acclimatisation before being set free.

When the biologists open the screen, some of the birds immediately hop out, but others are reluctant to spread their wings. They need encouragement.

“We allowed an hour for natural movement, and then if there were still some birds inside, a crew member would walk through in a zigzag pattern and encourage those birds to go out the door,” Blackford, the federal biologist, says.

Oteyza and the other biologists tracked each captive-reared bird. When the males warbled their special mating song to attract females, they listened in. When the sparrows built nests, they put dirt underneath to prevent flooding. Then they built low fences around the nests to ward off predators that might eat the eggs.

Approximately 30 percent of the juveniles survived, which is about average for captive-raised animals released into the wild. Some were picked off by predators, and some were killed by the parasite, but there is no indication that the disease is spreading throughout the population, Williams says.

If nothing else, the captive breeding “buys us time so we can find the cause of their decline and reverse it,” says state wildlife commission biologist Juan Oteyza.

To the biologists’ delight, all of the captive-raised birds “behaved like wild birds,” Oteyza says. When hawks flew overhead, they knew to hide. And while some captive-bred birds mated with others of the same background, some mated with wild birds. Then the females laid eggs and tended them until they hatched—another milestone.

At last, in September, the season’s young birds took flight for the first time. About 65 percent of them had one or both captive-bred parents.

It was what the scientists had been waiting for: They’d proven that the offspring of captive-bred grasshopper sparrows could thrive on their own and boost the wild population.

Tiny bird, big expense

To photographer Sartore, this marks a dramatic turnaround. “It’s been a remarkable story,” he says, “I thought it was over for them.” (Go inside Sartore’s Photo Ark.)

The wild population now numbers about a hundred, with 30 breeding pairs. It’s an improvement, Faulhaber says, although still far from the point of declaring them no longer endangered, so the captive-breeding program continues.

Meanwhile, in a deal announced in November, the family of deceased Subway co-founder Fred DeLuca donated 27,000 acres of undeveloped ranchland for preservation—land that contains about half of all the breeding pairs.

Getting to this point has cost more than $1.2 million (£878,000) mostly in federal Endangered Species Act funds. Why go to such lengths and expense to save such a tiny bird?

First, grasshopper sparrows help disperse seeds and serve as food for a variety of animals. Furthermore, Faulhaber says, conserving the grasshopper sparrow in its natural habitat means protecting the ecosystem for “all the other beautiful, valuable species that go together with them.”

“When we care about the ‘least among us,’ it can lead to broader environmental thinking, from consumer spending to saving rainforests,” Sartore says. “I think of the Florida grasshopper sparrow as a gateway drug for nature.”

Perhaps it’s the gateway needed to save the Cape Sable seaside sparrow, another rare sparrow species in Florida teetering on the brink of vanishing, Blackford says. Only 3,000 remain, all in the swamps of the Everglades.

“What we learn from saving the Florida grasshopper sparrow,” she says, “could inform the actions we take to try to save the Cape Sable seaside sparrow.”

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