The rufa Red Knot navigates from the top of the world to the bottom, and back, each year. According to the U.S. Fish and Wildlife Service, however, the knot — a subspecies of one of the largest and most colorful sandpipers — is likely to become in danger of extinction in the foreseeable future.
The Service recently issued a proposal to add the shorebird to the threatened species list on the Endangered Species Act. The proposal followed several lawsuits urging the Service to “emergency list” the shorebird, whose population has declined by about 75% since the 1980s.
If approved, the knots will join more than 1,200 species in the U.S. on the Endangered Species List. Only a handful of species have been removed from the list because of recovery.
Each year, the knots migrate from the Canadian Arctic to Tierra del Fuego, an archipelago off the tip of South America, a distance of more than 9,000 miles and one of the longest migration routes of any bird. To survive their journey, the knots touch down along the Atlantic Coast to feast on their favorite meal – horseshoe crab eggs.
In the spring, thousands of knots convene in the Delaware Bay, a stopover timed perfectly with the spawning of horseshoe crabs. During this visit, the knots eat enough eggs to double their body weight in just two weeks, enough to sustain them for the rest of their journey.
This refueling depends on an abundance of horseshoe crabs. Recent over-harvesting of horseshoe crabs, which are used for bait and biomedical research, has led to food supply shortages for the knots.
“Food availability is the best supported explanation for the recent decline that we have seen over the past 15 years,” said Wendy Walsh, biologist with the Fish and Wildlife Service.
Since the 1980s, the red knot population has fallen from 90,000-150,000 to between 15,000-20,000 birds.
In 1998, the Atlantic States Marine Fisheries Commission began issuing restrictions on the horseshoe crab harvest to address the issue of over-harvesting. Last year, the Commission enacted a new model called the Adaptive Resource Management framework. The model accounts for the abundance of red knots and horseshoe crabs and determines an optimal harvest package for fishermen.
The model is an improvement over prior efforts to restrict crab harvesting, said wildlife biologist Larry Niles. However, it is not without its limitations.
“What the agencies aren’t talking about are the assumptions in the model,” he said. “The assumptions are that there’s no illegal harvest. There’s the assumption that crabbers taking females aren’t calling them males.”
From the Commission’s perspective, there is currently an adequate supply of eggs for the red knots in the Delaware Bay, said Marin Hawk, Fishery Management Plan Coordinator. “The concern [for us] is when the red knots are not in the Delaware Bay – when they’re in South America – it’s difficult to determine what’s happening to them.”
In some countries in South America, red knots are hunted for sport, in others for subsistence. Even in the U.S., there is a history of very intensive hunting of shorebirds around the second half of the 1880s. Increased conservation efforts resulting from the listing may help to address this threat.
Following the proposal to list the bird as threatened, the Fish and Wildlife Service launched a 60-day open comment period, to end on November 29. During this period, the Service considers comments related to available scientific data, and ignores opinion commentary, such as the bird’s charismatic appeal.
If the decision stands, the Fish and Wildlife Service will have one year to develop a recovery plan.
In rare cases, listing a species as threatened, which leads to increased funding for research and protection, helps populations recover to the point where the listing is no longer needed.
As of 2012, there were 28 species, out of more than 1,200, whose populations recovered to the point where they could be removed from the list.
Niles believes the red knots have a shot at number 29.
“If we are able to restore the Delaware Bay, if we’re able to apply some of the protections the listing affords in the bird stopovers, along with protections the Canadians have built in the breeding areas, and the protections the South Americans have created in the wintering areas, I think we can bring the bird back,” he said.
Comments
December 13, 2013 at 8:42 am
Nice article which provides some hope for species recovery in this holiday season. Well written.