For the dusky seaside sparrow the end has come, not with a bang, but with a lonely twitter. The species, always reclusive and rare in the Florida salt marshes it once inhabited, is now a population of one.
Shielded from public view, the last known dusky seaside sparrow on earth, a graying 12-year-old male, blind in one eye, now resides in an unobtrusive screened cage at a Disney World zoological park.
There, among tufts of its native cord grass, it is nesting this spring for what may be the last time–a union with a related species that scientists hope will help preserve at least some of the bird`s genetic traits in future generations of seaside sparrows.
But scientists fear this will be the last time that anyone hears the mating call of the dusky seaside sparrow.
Twenty years after the species was first declared endangered, the hopes of bird lovers and biologists now hinge on a single, lilting song and the opportunity to salvage one or two more pinkish eggs the size of a navy bean, and perhaps, if breeders are really fortunate, one last frail and hairless chick.
”It`s sad, but for the dusky seaside sparrow, this is really the end of the line,” says Marshall Jones, chief of endangered species programs for the U.S. Fish and Wildlife Service`s regional office in Atlanta. ”When this one is gone, there won`t be any more.”
As the last representative of the species, the remaining sparrow mirrors the story of the passenger pigeon. Millions of them once darkened the skies of America. The last one died in a Cincinnati zoo in 1914.
As the second bird to become extinct since the U.S. Endangered Species Act was passed in 1973, the dusky`s obituary will reflect that it was the victim of the nation`s space program, a superhighway, Florida development and years of bureaucratic indecision.
As a practical matter, the fate of the shy little sparrow was tragically clear in 1980 when, in a desperate effort to save the species, wildlife biologists rounded up the last birds in the wild.
The birds were intended to be the nucleus of a flock that would perpetuate the species in captivity. There was just one problem. Biologists had found only five birds–and all five of them were males.
Since then, old age has taken its inevitable toll. In 1983, four
”duskies” remained alive. Last year there were two. Now, since the death on Feb. 10 of another 10-year-old male, there is only one.
”No dusky seaside sparrow has been seen in the wild since 1980,” says Charles L. Cook, curator of Disney`s Discovery Island, where the surviving birds have been housed since 1983.
During the last three years, Disney officials and the Florida Audubon Society have cooperated in a controversial program to crossbreed the remaining birds with the Scott`s seaside sparrow, a more plentiful native species of the Florida Gulf Coast.
Through successive ”cross-back” matings, they had hoped to produce a substantial flock of hybrid sparrows that, after five breeding seasons, would be 97 percent dusky–outwardly indistinguishable from the real thing.
It was not to be. There are no dusky seaside sparrows in the public exhibit cage at Disney World these days. The most endangered species is now too rare to be put on public display.
Standing between the Brazilian toucans and Discovery Island restrooms, pert, gold-uniformed Disney tour guides still tell tourists that ”the two remaining sparrows” are part of ”a project for salvation.”
The real outlook, however, is decidedly grimmer.
The low fertility of the captured males–and their declining numbers
–have left the efforts to reconstitute the species far short of its original objectives. Of nine hybrid eggs laid last year, only two hatched. Instead of scores of hybrid birds, there are only five, and only one that is 87.5 percent ”dusky.”
”We had hoped for as many as 15 birds a year, so we are obviously way behind,” says Dr. Herbert Kale, the Audubon ornithologist who conceived the project. ”At this stage, it looks pretty hopeless.”
In spite of the setbacks, Disney and Audubon intend to press ahead with the breeding program–even after the death of the last dusky.
”If nothing else, what we are doing is symbolic,” Cook says. ”As long as there is one bird that has 1 per cent dusky genes, we will have
accomplished something.”
Regardless of the degree of their racial purity, the hybrid sparrows face an uncertain future. In the view of the Fish and Wildlife Service, they are non-species–deserving neither federal protection nor the right to be released on federal lands.
Although some conservationists blame the federal government for waiting until it was too late to begin rounding up the last birds in the wild, the underlying causes of the species` collapse are not easily isolated.
First discovered in Florida`s Brevard County in 1872, the dusky seaside sparrow apparently never strayed outside a 10-mile radius of the spartina grass marshes along the lagoons of Merritt Island and the upper St. Johns River.
After the area was selected as the site for the nation`s spaceport, authorities built an extensive system of dikes and levees to control the mosquitoes that made the area all but uninhabitable. In the process they drowned mosquito breeding areas and the marshes that supported the largest colony of dusky seaside sparrows.
Near Possum Bluff on the St. Johns River, a second, smaller colony of the birds` marshes went into a sharp decline in the early 1970s as a result of drainage projects, a succession of destructive wildfires, and the extension of the Beeline Expressway, built to speed traffic from the Florida Spacecoast to fast-growing Orlando.
By 1976, only 11 male sparrows were counted in the St. Johns marshes, and by the time the federal government moved to save the species, they were unable to locate a single female.
”They acted too late,” Kale says. ”But it was probably the wildfires that delivered the coup de grace. There`s lots of blame to be shared by lots of people for this one.”
Some biologists, such as Cook, still cling to the faint hope that in some remote, still undeveloped corner of Florida`s coast, someone, someday will discover a ”lost colony” of dusky seaside sparrows.
Before the bird is officially stricken from the list of endangered species, Kale intends to ask the federal government to conduct ”one last, intensive search” of the region for the little birds.
”Once this last bird dies, I would have to say that the dusky seaside sparrow will probably be extinct,” he says. ”But Mother Nature loves to make liars out of biologists. This is one time I wish she would.”
Cox News Service. Distributed by the New York Times News Service
