June 7, 2006
NJ Biologists Fight to Save Rare Bird from Extinction
By Jon Hurdle
REED'S BEACH, New Jersey -- On a remote New Jersey beach, a team of biologists huddled behind a dune, out of sight of a flock of birds that gathered on a stretch of sand.
Rushing to untangle the birds, the team released the sea gulls and then gently placed the other species -- all shorebirds -- into cardboard boxes and plastic crates.
Their haul included sanderlings, semi-palmated sandpipers, ruddy turnstones and, to their great satisfaction, 24 specimens of one of the most endangered shorebirds in the world, the red knot.
The red knot, a 10-inch-long (25-cm-long) bird with a rusty red breast and mottled gray back, is the subject of increasing alarm among naturalists because its population has dwindled in the last decade to levels that may lead to extinction in the next five years.
This year's count by the New Jersey Department of Environmental Protection -- which has monitored the bird since 1986 -- found the population dropped to some 13,000 from 15,000 last year and now equals the record low set in 2004.
The latest tally compares with 100,000 or more birds in the mid-1980s, the number that biologists consider sufficient for the species to survive.
With just 13,000 birds left, the red knot species is highly vulnerable to natural dangers such as bad weather in its Arctic breeding grounds, biologists say.
"This bird is on the edge of extinction," said Larry Niles, head of New Jersey's endangered species program. "The population now is so low that there's any number of influences that could cause further decline."
A scientific model published in 2004 projected that by 2010, the red knot could join the passenger pigeon, the Eskimo curlew and the Bachman's warbler on the list of species that have been lost forever.
New Jersey's beaches are critical to the survival of the red knot because they are a stopover on the bird's epic migration from Tierra del Fuego in southern Argentina to northern Canada where it breeds.
The 12,000-mile (19,300-km) journey by the 4.7-ounce (135-gram) bird is one of the longest avian migrations, and it includes stretches of nonstop flying for at least 3,000 miles , scientists have found.
Each May on the Delaware Bay beaches, the bird traditionally replenishes depleted fat reserves by gorging on the eggs of horseshoe crabs that come ashore to spawn every spring. With plenty of eggs, the red knot can double its body weight and provide the energy reserves it needs to reach the Arctic.
But numbers of horseshoe crabs have plummeted since the early 1990s because of over-harvesting, both on- and off-shore, by commercial fishermen who use the crabs as bait for conch and eel.
The supply of the eggs is now a mere 5 percent of what it once was and, with insufficient food for their journey, some red knot don't leave New Jersey, others may not make it to their breeding grounds or may be too exhausted to breed if they do arrive.
New Jersey this year imposed a two-year moratorium on taking horseshoe crabs, but biologists say Delaware and Virginia, which also border the Delaware Bay, need to do the same.
In a bid to provide undisturbed feeding for the red knot, New Jersey closes 15 beaches at migration time in May each year. Also, an interstate organization that regulates fishing in the area has said only male horseshoe crabs can be harvested.
New Jersey's moratorium, which has angered some local fishermen, should help boost the egg supply, but it will be three or four years before the current generation of young horseshoe crabs are old enough to start producing eggs, Niles said.
The federal Fish and Wildlife Service last year declined to make the red knot an officially endangered species, a status that would have given it a range of protections. New Jersey Audubon and other conservation groups are jointly preparing a legal challenge to that decision, said Joanna Wolaver of New Jersey Audubon.
At Reed's Beach, Niles' team -- which includes volunteer ornithologists from Britain, Australia, Argentina and Taiwan -- weighs and measures the captured birds, taking blood and feather samples and adding rings and tags that will enable the birds' movements to be traced when they are next captured.
They release them as quickly as possible to minimize any stress on birds that might be among the last of their species.
"We need to get this boy on the road," said DEP biologist Amanda Dey, holding one bird before releasing it. "He's been handled a lot, and he needs to go."