Shoring Up the Red Knot

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Conservationists rush to save a bird on the brink

By Caitlin Leutwiler

red knot, © Jan van de Cam / Life Along the Delaware Bay

© Jan van de Cam / Life Along the Delaware Bay
“Three… two…one!” It seems the countdown has hardly begun when the cannon fires. I run alongside a dozen scientists in a mad sprint down New Jersey’s Cooks Beach to the ejected net, now filled with about 60 flapping birds. 

Already at the net, shorebird expert Larry Niles is shouting instructions to the group. I step aside to let those with more experience untangle the birds. With the tide coming in, it’s imperative they are removed quickly. Several species hop around in the net but we’re after only one: the red knot, a robin-sized shorebird named for its rust-colored chest. All the others are quickly freed and fly away. The red knots will also be released, but not before we collect some data.

Suddenly, someone thrusts a bird in my hands and shouts, “We got one with a locator!” A glint from the tiny yellow band on the red knot’s leg catches my eye. The group cheers but doesn’t stop working. After half an hour of sorting through dozens of birds, we count nine red knots in all—and consider it a good catch. 

Less than two decades ago, the scene would have been much different. Back then, red knots filled the skies of Delaware Bay during their epic spring migration from South America to breeding grounds in the Canadian Arctic. More than 100,000 of the birds stopped here to rest and feed on the bay’s abundant supply of horseshoe crab eggs—the bay is the largest spawning grounds for horseshoe crabs in the Western Hemisphere. But their overharvest for use as bait in the commercial conch and eel fishery caused the crash of the crab population beginning in the late 1990s, decimating the red knot’s food supply. As the number of crab eggs plummeted, so did the red knots. 

Now, fewer than 13,000 of the birds make their way to the bay, a number that continues to decline steadily. “This species is literally disappearing before our eyes,” says Jamie Rappaport Clark, Defenders’ president. “With population numbers this low, red knots may already be on an irreversible slide to extinction.” Defenders has fought for federal protections for the bird since 2005, but each call for help has been denied. Clark says the failure to act is purely political, and if there was ever a time to invoke the protections of the Endangered Species Act (ESA), she says, this is it. 

Delaware Bay declared area of global significance for migratory shorebirds

Progress came for red knot protections in December, when 50,000 acres of Delaware Bay beaches, wetlands and forest was declared “an area of global significance for shorebirds.” The designation helps direct resources to places harboring the most significant bird populations, facing the greatest threats or having significant management needs. Delaware Bay was selected based largely on its importance to red knots as well as ruddy turnstones, black ducks and snow geese.

“Hold it like a football,” says Susan Taylor, an Australian bander, as she hands me a red knot. Despite my rookie status, I’m quickly put to work beneath the tarp set up to shelter the data stations from the rain that’s beginning to fall. We work in a close circle, collecting weight and wingspan measurements and feather samples, and gluing identifying bands around the birds’ legs. I’ve been tasked with taking feather samples, and my reluctance to pluck the three feathers from each downy chest is obvious. “It’s like taking off a Band-Aid,” Taylor instructs me. “Nice and quick.” 

Our small tent boasts experts traveling from Argentina, Australia, Canada, Great Britain, Kenya and New Zealand. All speak the same language: bird. “This loose collective of researchers has been providing the data for the status updates every year for the past decade,” says Mandy Dey, with the New Jersey Division of Fish and Wildlife.

What the collective found this year was particularly troubling. Aerial and ground counts of the main wintering population of red knots in South America revealed a decline from the previous winter of at least 5,000 birds—approximately one third of that population. “It’s a big drop to lose that much of the population in just one year,” says Niles, who reads catastrophe in the numbers. “It doesn’t bode well for the population.” Such a drop could be the result of a spate of tropical storms in the Caribbean—red knots may have run into trouble on their way back to Argentina.  But my companions are inclined to believe it’s a result of the continued dwindling of horseshoe crabs at Delaware Bay.

In 2008, the state of New Jersey took action to reverse the horseshoe crab loss, putting a moratorium on the crab harvest in state waters. But the Atlantic States Marine Fisheries Commission—the government agency that oversees the horseshoe crab fishery—failed to follow suit for the region. While Delaware voluntarily eliminated harvest of female crabs and reduced male harvest to 100,000, Maryland and Virginia continue to harvest approximately the same number of male and female crabs. Female crabs are favored for bait because of the eggs they contain in their body. As a result, overall horseshoe crab fishing hasn’t been reduced, crab numbers haven’t increased and neither has the amount of eggs on the beach. 

In recent years, another threat has emerged: the bleeding of horseshoe crabs for biomedical purposes. Horseshoe crab blood is unique not only because it’s blue but because it contains a substance called Limulus amoebocyte lysate (LAL), used to test for bacterial contamination in products ranging from vaccines to surgical implants. LAL binds to bacteria, forming a telltale clot. Historically, the LAL industry was not thought to seriously impact the crabs because blood is usually extracted without killing the crabs, and the bled crabs are returned to the water. 

However, little is known about the care the crabs receive during their time out of the water, and with few regulations regarding their handling, concern is increasing about mortality associated with the bleeding process. In fact, the mortality rate for female crabs may be as high as 30 percent—far greater than the standard estimate of 10 percent to 15 percent for both sexes—according to a recent scientific study from the Waquoit Bay National Estuarine Research Reserve in Massachusetts.  

Larger than their male counterparts, female horseshoe crabs contain more blood, and so are more attractive to the industry. But they’re also critical to recovery of the Delaware Bay crab population, and Niles believes that at this level of mortality, the industry could be seriously impacting the species. 

“We need Delaware Bay to recover right now,” says Niles. “The lysate industry is worth $200 million annually, but it is doing virtually nothing to protect the crabs and may actually be causing the problem.” More than 500,000 horseshoe crabs are bled each year, and it’s a number that is expected to grow dramatically each year as the industry expands.

Until better oversight and management practices are put in place, habitat protection is critical to keeping the diminished red knot populations stable. And that’s where today’s banding and information-gathering comes into play. 

Banding is important to red knot survival in several ways. For one, it allows scientists to track birds from year to year simply to see if they’re surviving. But the color-coded bands also tell scientists where the birds are spending time. For example, a bird with a green tag on its leg tells scientists it was tagged in the United States. Orange or red tags mean the bird was tagged in Argentina or Chile.  The red knots carrying geolocators are more precise. These tiny devices glued to a yellow band carry computer chips that record light exposure and captures the time of sunrise and sunset. Because this differs based on latitude and longitude, researchers can actually pinpoint where the birds have spent their time, and which migration routes they took to get there. This data allows greater understanding of the shorebirds’ habitat uses and needs. 

While precise, these locators are expensive, and fewer than a dozen are affixed to red knots each year. So when the first knot to come out of the net was bearing one, these scientists knew they had hit the jackpot.

The tiny piece of technology revealed that the bird had migrated to the Arctic last year, successfully nested, then headed south through Cape Cod and over the ocean to South America, ultimately touching down in Tierra del Fuego, Chile. Before long, it had made the reverse flight back to our New Jersey beach. I couldn’t believe it: This bird had traveled tens of thousands of miles, and here I was holding it in my hands.

The epic journey of the red knot is impressive, but it also complicates conservation efforts. Experts like Niles and Dey believe that the federal government has not acted quickly enough on efforts to save the bird thus far because red knots don’t breed in the United States. Since 2005, Defenders and its partners have submitted four formal requests to the U.S. Fish and Wildlife Service (FWS) to protect the red knot under the ESA. Citing a lack of resources and other priorities, FWS failed to list the bird but placed it on the candidate waiting list in 2006. Since then, red knot numbers have continued to fall. “It’s time the United States upholds its responsibility to the global community to protect this migratory shorebird,” says Clark.

Hope, however, may finally be on the horizon for the imperiled bird. In July, FWS announced the decision to speed up the process to add the red knot to the list of threatened and endangered species. The news could be a game-changer for the birds. A listing would begin the development of a species recovery plan and require federal agencies whose actions affect red knots to consult with FWS. It would also mandate the designation of critical habitat, adding a layer of protections to the places where red knots gather.

But all this takes time. And that’s something red knots may no longer have. The bottom line remains: Without an increase in horseshoe crab eggs, and soon, there may not be hope for knots.

That’s why collaboration between shorebird experts and the biomedical industry is so important. “The best thing we can do is to get more eggs on the beach quickly,” says Dey. “That means stop harvesting females for bait, stop or severely reduce the bleeding of female crabs for pharmaceutical purposes and institute best-management practices to reduce the mortality of all crabs that are bled to less than 5 percent.” 

Before I know it, the last bird is returned to shore, rushing off to resume refueling for the final leg of its journey to the Arctic. With only days for the knots to redouble their weight on protein-rich crab eggs, there is no time to waste. Sticky with saltwater and glue from the colored tags, my adrenaline runs high. I’m not the only one giddy from the haul. “Delaware Bay is completely different every year,” says Dey as she looks out onto the water. “You never know what you’re going to get. Luck was on our side this year when we recovered the geolocator. Let’s hope even greater fortune is in store for the red knot in years to come.” 

Caitlin Leutwiler is a communications associate at Defenders of Wildlife whose favorite place to watch shorebirds is on New Jersey’s Long Beach Island.

Go behind the scenes with Caitlin Leutwiler on her reporting trip to Cooks Beach.

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