Rare birds born in lab now nest in nature
Florida grasshopper sparrows breeding in wild after release
A desperate attempt to rescue Florida grasshopper sparrows from extinction by breeding a small population of them in captivity appears to have led to an astounding success: many of those released laboratory birds are now nesting in the wild.
Larry Williams, supervisor of U.S. Fish and Wildlife ecological services in Florida, on Friday called the development a “a major, major milestone,” though so much is still unknown about the grounddwelling bird’s recent plunge toward oblivion.
“This initial success with captive-reared Florida grasshopper sparrows breeding in the wild is a testament to and confirmation of all the hard work our partners,” Williams said.
When the captive birds were first released in May last year, there was a shared dread among researchers and biologists that the young sparrows, having only known the insides of pens, would soon experience the insides of predators.
“When you start thinking of all the things that could go wrong on release — would hawks and snakes gobble them up? Could they find food? Would they know how to breed and raise young?” said Audubon Florida biologist Paul Gray. “I can’t describe the years of anxiety all of us have had. I feel better about the sparrows than I have for about 20 years.”
The species is only found in treeless prairies south of Orlando in Osceola, Polk, Highlands, and Okeechobee counties.
The small, brown birds have a song like a buzz and are rarely seen by people, and so lack the charismatic appeal of larger birds that have been the focus of intensive rescues, including bald eagles and California condors.
But the sparrows have drawn the attention of a small coalition of federal, state, academic, nonprofit and environmental participants, who have relied on donations and grants to supplement government funding.
By last year, the species’ population had collapsed to just 30 breeding pairs.
Efforts to hatch and raise them in captivity began about five years ago and slowly accelerated. Since releases of captive-raised birds began a year ago, nearly 150 have been introduced to the wild.
Though extremely difficult to track, researchers have documented that more than 25 of the released birds are defending territories. Of those, eight sparrows are nesting, and two of the birds have fledged young.
“The finding that captivere-ared sparrows can breed in the wild is a game-changer,” said Juan Oteyza, research scientist at the Florida Fish and Wildlife Conservation Commission’s Wildlife Research Institute. “This indicates that individuals bred in captivity can supplement wild populations and therefore reduce the risk of extinction.”
Biologists caution that successful rescue of the bird still hinges on bolstering their ability to survive on their own.
“We still don’t know the cause of their decline,” said Mary Peterson, a U.S. Fish and Wildlife Service sparrow-recovery biologist of efforts to tease out specific solutions from amid broader problems. “We know the threats of habitat loss, high predation of nests and high adult mortality in the winter.”
But the preliminary success with birds raised in captivity has come after years of uncertainty and doubt about whether to even remove birds from nature, what to feed them, how to care for them, how to prepare young chicks for release and how, when and where to release them.
While none of that had ever been done before, the mission was haunted by the outcome of a previous attempt to save a bird from extinction.
When the dusky seaside sparrows of Central Florida dropped sharply in numbers in the late 1970s, a captivebreeding program was launched. All the known remaining birds, about a halfdozen, were removed from the wild, but each was a male. Dusky seaside sparrows were declared extinct in 1990.
Rescuing Florida grasshopper sparrows appears headed along a far different path.
“For all of the trial and tribulations we’ve had over the last couple of years, this is very optimistic milestone,” said Ashleigh Blackford, a supervisory biologist at the U.S. Fish and Wildlife Service.