Florida Grasshopper Sparrow reaches record low numbers; extinction looms

12/13/2017 | 0

Florida Grasshopper Sparrow

Florida Grasshopper Sparrow. Photo by Neil Pearson/FWC Fish and Wildlife Research Institute (Creative Commons)

The U.S. Fish and Wildlife Service and its partners are working to stave off the extinction of a small, ground-nesting songbird that has lived on the prairies of South and Central Florida for thousands of years. If current trends continue, Florida Grasshopper Sparrows could disappear from the landscape in two to three years.

In 2017, the subspecies reached a record low of about 75 wild birds — down from 1,000 birds in 2004. Trends suggest the population will be less than 40 wild birds in 2018. Only about 50 birds are being sustained in two captive populations. Restoring a self-sustaining wild population seems unlikely, the agency says, but groundbreaking scientific strides are underway in an effort to beat the odds.

“We still don’t know exactly why the population is declining, but we are concerned disease is a big factor,” said Larry Williams, the Florida state supervisor for Ecological Services. “Extinction is a real possibility, but we’ve got to try to save this species.”

Extreme weather events are among the threats to the bird. It’s unknown what impact Hurricane Irma had on the wild population because the storm occurred after the breeding season. However, an aviary where captive chicks were hatched lost power during the storm. Only hours before a backup generator would have failed, a service truck delivered 100 gallons of fuel to the facility, allowing the chicks to survive.

Scientific breakthroughs

Since 2012, FWS and its partners have invested more than $1 million into saving Florida Grasshopper Sparrows. Major scientific breakthroughs have occurred thanks to the funding:

  • captive breeding — Florida Grasshopper Sparrows were successfully bred in captivity for the first time ever;
  • habitat management — Refined timing of prescribed fire has lengthened the nesting season and boosted nesting success; and
  • predator management — Fences to exclude predators have raised nesting success from eight to 84 percent.

But in spite of those breakthroughs, sparrow numbers continue falling.

The Florida Fish and Wildlife Conservation Commission (FWC) and Archbold Biological Station are leading monitoring efforts and establishing protective fences around nests to reduce predation and boost numbers. The White Oak Conservation Holdings and the Rare Species Conservatory Foundation (RSCF) — with strong support from the Service — have started two captive breeding facilities aimed at producing sparrows for release back into the wild.

Florida Grasshopper Sparrow, held by a researcher. Photo by Mary Peterson/USFWS

Florida Grasshopper Sparrow, held by a researcher. Photo by Mary Peterson/USFWS

Over the last five years, private ranchers and land stewards, including Avon Park Air Force Range, Kissimmee Prairie Preserve State Park, and Three Lakes Wildlife Management Area, have been managing dry prairie to optimize habitat for the sparrows. “One of the private ranches has the second largest population of these sparrows in the wild,” Williams said.

Partners are determined not to let the Grasshopper Sparrow meet the same fate as the Dusky Seaside Sparrow, which went extinct in captivity in 1987. The initial reasons for these species’ declines are similar: loss and fragmentation of habitat, combined with suppression of fires needed to maintain habitat. Florida Grasshopper Sparrows are also impacted by red fire ants, which were introduced from Brazil around 1940.

“The Dusky Seaside Sparrow, which was unique to Florida, just like the Florida Grasshopper Sparrow, was the last bird to go extinct in the continental United States,” Williams noted. “No one wants to see that happen again.”

And while these efforts are geared toward Florida Grasshopper Sparrows, Andrew Schumann, White Oak’s avian collection manager, says what’s being learned about the sparrows will be helpful with other species across the United States.

“The stuff we’re finding out has implications for many different songbirds and other species. This isn’t going to be the only species that declines and is reliant on a captive breeding and reintroduction program,” he said. “Even if we do our absolute best to conserve the Florida Grasshopper Sparrows and it still goes extinct, what’s next? Is it the Bachman’s Sparrow? What we’re learning now could make a difference.”

Cause of decline unknown

Ultimately, Schumann believes that they’ll find success with the captive breeding program because he’s seen that these birds can “crank out chicks” in a captive setting. His overriding concern is that the cause of the rapid decline in the wild is still unknown. “We’ll work out the kinks in the captive breeding program, but we’re never going to succeed until and unless we find out why the population is declining,” he said.

“The wild situation is desperate,” said Paul Reillo, the RSCF’s director. “Therefore, captive breeding, which is always a last resort, is where we should focus our efforts before we run out of time.”

Captive breeding efforts were started in 2014 with FWS funding, but nobody had bred Florida Grasshopper Sparrows in captivity before, so species-specific techniques are being worked out.

The past year of captive breeding has been beset by losses to the captive population from diseases that may or may not be affecting the wild population.

“With captive breeding there are always challenges and the only way to work them out is by trial and error. Research has been initiated to determine the specific strains of the diseases, evaluate their presence in the wild population, and to find solutions,” Williams said.

So far the partners have broken new ground by working out incubation settings, proper diet, and housing strategies to help encourage natural “wild” behavior. They’ve also identified and begun to treat for parasites.

Captive breeding programs have successfully rescued species from the brink of extinction — including the Peregrine Falcon, Puerto Rican Parrot, and black-footed ferret.

So, coupled with the fact that a recent look at genetics showed that the sparrows’ current genetic diversity is similar to its historic genetic diversity, captive breeding shows real promise as the birds have a high reproductive potential. FWS is collaborating with scientists and other stakeholders to work out the techniques. Funding for all partners, however, is limited.

Last spring, the Fish and Wildlife Foundation of Florida started a sparrow fund through the foundation’s website for anyone to contribute to the survival and recovery of the bird.

As of mid-November, this fund had approximately $10,500. Contributions will support captive breeding by constructing more enclosures that mimic natural habitat and encourage natural behaviors of the sparrows, care of captive birds, preparations for releasing captive-bred birds back into the wild and mitigating threats such as predators and flooding.

From May 2016: Captive-bred Florida Grasshopper Sparrows make conservation history

 

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