But wildlife experts and scientists say the birds could disappear from the East Coast because of dangers to their habitats and food supply. Those concerned are pushing the state to declare the red knots a threatened species in the Garden State.

While on the New Jersey shore, the birds need to feed on the eggs of horseshoe crabs to build up the energy they need to get them to the Arctic and through the breeding season.

But heavy fishing of horseshoe crabs has wildlife experts worried, because there may not be enough eggs left for the birds to feed on, The Asbury Park Press reported in Sunday's editions.

"The key problem is 80 percent to 90 percent of the red knots that breed in Canada go through Delaware Bay. Anytime you have a bottleneck like that, there's a danger of decimating the whole species with an event like an oil spill or a food shortage," said Joanna Burger, a professor of ecology and evolution at Rutgers University.

By designating the species as threatened in an upcoming issue of the state register, the state would be signifying a policy shift toward protecting the birds from pollution accidents and would strengthen the position of environmentalists who want restrictions on horseshoe crab fishing.

Gov. Christie Whitman banned crab harvesting for four months in 1997. Of the state's 350 bait crabbers, 90 percent have lost permits because they couldn't meet new rules.

Wildlife experts said the number of red knots visiting the shore has risen from a 1996 low of 19,000. But they are concerned because the birds seem to be taking longer to find the food they need, staying three weeks to four weeks instead of two.

Horseshoe crab concentrations have been spotty on the shore, with the biggest mass at Slaughter Beach on the Delaware side of the bay. In 1997, 91 percent of the birds clustered on one stretch of Delaware beach.

After leaving New Jersey at the end of May, the birds arrive in the Arctic in the first half of June, and immediately get into courting and breeding.

"The logic says the fat they bring in from their last staging site (Delaware Bay) is probably essential," said Brian Harrington, a scientist at the Manomet Center for Conservation Sciences in Massachusetts.

Burger said having the state designate the birds as threatened "is a very key and important step.

"We can't control what happens on the Arctic breeding ground," she said. "What happens here is critical."