In southern New Jersey scientists struggle to protect some of the planet's greatest migrators from disappearing. Living on Earth's Mitra Taj reports on the effort from the Jersey shore.
GELLERMAN: The Jersey Shore is the scene for the reality TV show that made "The
Situation" a household name, but for scientists and birders, the real situation is the
survival of New Jersey shorebirds, whose migratory flight takes them all the way to
Antarctica and back.
Mitra Taj caught up with some of the birds' biggest backers to document the dramatic
effort to save them.
[BIRD SOUNDS AND WAVES]
TAJ: If you want a visual of bird species in decline, don't come to the Delaware Bay
in the summer. Here at Reeds Beach, small flocks of birds crowd the shore and swoop
through a pastel sky.
DUNCAN: I just arrived, and to get here and see thousands of birds in the air is really a
wonderful thing - a hopeful sign.
TAJ: Charles Duncan leads the effort to protect the birds for the Manomet Center for
Conservation Sciences. He used to be a chemist. That was before he became obsessed
with shorebirds, in particular red knots—the small plain-looking birds poking their beaks
into the sand… a closer look reveals the reddish chests of males strutting the beach. But
their plumage isn’t what’s attracted Duncan:
DUNCAN: You know, if you just walked up to somebody on the street and said, "do
you imagine that a bird that weighs the same as an iPhone could fly from southern South
America to New Jersey," they would tell you to stop smoking that stuff. They would look
at you like you’re crazy, but here it is, and these birds that we're looking at in front of us
have done exactly that.
TAJ: And they’re about to do a lot more. The Delaware Bay in southern New Jersey is just a rest stop for the red knot. After coming all the way from Tierra del Fuego near Antarctica, they set off for the Canadian Arctic, where they mate and lay eggs.
Oh, and by the way, the birds you hear in the background aren’t red knots. They’re local laughing gulls. Here’s the red knot, courtesy of the Cornell Lab of Ornithology:
[RED KNOT FLIGHT SONG -- HIGH PITCHED CHIRP]
TAJ: That’s the bird’s flight song, a tune it gets plenty of time to practice. Red knots spend about a third of their lives flying back and forth across the planet - about 18,000 miles a year. One red knot Duncan’s been tracking could have flown to the moon by now.
DUNCAN: So they're some of the greatest migrants of any species on the planet.
TAJ: And… they’re in decline. Larry Niles works as a biologist with the Conserve Wildlife Foundation of New Jersey:
NILES: So when we first started our work, we had over 90,000 red knots come to the Delaware Bay. And, last year, we had just over 16,000, and this year we're not sure if there's evening going to be 10,000.
TAJ: In ten years the total red knot population has shrunk to less than a fifth of what it used to be. While other countries have listed the red knot as an endangered species in need of protection, the United States hasn’t yet. It’s waiting in the endangered species
listing backlog at the Department of Interior.
TAJ: But Duncan and Niles aren’t alone in their efforts. Every year, a small army of volunteers helps them gather intelligence on shorebirds that could help slow their decline. They meet in a Jersey beach-house to plot strategies, then scatter over the beach armed
with walkie-talkies and scope binoculars. Some crouch behind sand dunes, others watch their feathered targets from the cockpit of a Cessna.
NILES SHOUTING: Here comes the plane, Clive!
[INAUDIBLE WALKIE-TALKIE RESPONSE]
[PLANE NOISE UP AND UNDER]
TAJ: As the plane presses into the shore, the sky fills with birds, and volunteers inside the plane visually estimate how many have taken flight.
NILES: See all the birds coming up there, that's exactly what we want because you can't count the birds on the ground.
TAJ: It’s a skill that takes years to perfect.
NILES: You have to have a mental image of what a thousand birds looks like, so that you can go, 1-2-3-4-5 thousand, while you're flying by at a hundred miles an hour.
DUNCAN: People get really good at it, it’s surprising. You get a sense of how 60 looks different from 53.
TAJ: This year, after conducting counts like this every three days, the news wasn’t good. The number of red knots visiting the Delaware Bay appears to have dropped by another couple thousand.
While they still can, Duncan and Niles want to learn from the birds. How do they survive such a long voyage? What tells them which way to go?
Eight years ago, a new technology opened a window into the secret life of the red knot. Geolocators, little bands placed on the birds’ legs, record the time of sunrises and sunsets as they make their journey. Because every part of the world has unique sunrise and sunset times, they can put together a day-to-day diary of where a bird has been. Larry Niles and Charles Duncan:
NILES: The results are stunning, we're finding birds making these heroic journeys that go from wintering areas in Uruguay, flying straight across the Amazon, straight across the Atlantic to North Carolina, or Delaware Bay, all in one shot, not landing, just flying for 8 thousand kilometers in six days straight. It's, you know, this is an impressive animal, and you don’t really get the feel for that until you see the tracks of these individual birds.
[THUNDER, LAUGHING GULL SOUNDS]
DUNCAN: One of the geolocators caught not so long ago was of a bird that landed at Hudson Bay, Ontario and flew 300 miles south to James Bay and then flew 300 miles back, for whatever reason, I mean make up whatever story you want about it — true love
or go see his brother-in-law or heard a rumor that there was good food or who knows -but distance seems to mean nothing to them if they're in good shape.
TAJ: If they’re in good shape. Good shape means they should leave Delaware Bay weighing at least 180 grams. They have to double their weight in two weeks to have a good chance of survival in the Arctic. And the birds arrive here not just hungry from the long flight, Duncan says, but physiologically altered.
DUNCAN: They reduce their digestive system, they reduce their gonads to almost nothing for this migration. So when they get here, they can only eat the softest of foods. They can't eat clams and mussels that they'd normally eat.
TAJ: Delaware Bay offers up a special menu: the soft eggs of the hard horseshoe crab: a prehistoric arthropod that looks something like a WWII battle helmet.
DUNCAN: Horseshoe crabs lay eggs on the beach here, and they lay them deep - they dig them down and the next crab that comes on, when the crabs are super-abundant as they were twenty years ago - the next crab digs up the other guy’s eggs, and brings them to the surface where they are the perfect food for these birds.
TAJ: Horseshoe crabs dot the beach here. This is their breeding headquarters, but there used to be many more of them. In the 90s commercial fisherman began harvesting them for bait, and Larry Niles says the rest is history:
NILES: As the horseshoe crab population started to decline from overharvest, the percent of birds that were making that critical weight - about 180 grams - started dropping until about 2003 almost no birds were making weight, and so then we saw a rapid decrease in the number of knots.
TAJ: Today, more than 60 percent of red knots still aren’t packing on the grams fast enough. And finding food is no longer the only challenge to their survival. Climate change is throwing unpredictable weather their way. Charles Duncan:
DUNCAN: As storms get more frequent, we're certain that that will lead to increased mortality of birds flying south, and that's our best guess, at the moment, for what happened last year, where knots left in good condition apparently, probably bred in good condition, started their southbound migration, and if you remember, we had four or five really very strong Atlantic hurricanes last year, so they're flying right into the teeth of these storms.
[SOUND OF WALKING ON BEACH]
TAJ: Right now, the biggest battle in the struggle to preserve the red knot is to capture a group of them, so they can be weighed and tagged. The data strapped onto the legs of red knots wearing geolocators can be downloaded, and new journeys revealed. The team has only a few weeks to capture and release shorebirds before they head north.
NILES: So we have a net set on the beach, buried in the sand.
TAJ: A large net attached to three cannons lies hidden on the beach. On cue the scientists can fire the projectile web, which is spread by metal rods in the air:
DUNCAN: You could easily kill a person if you were sloppy with this.
TAJ: Or kill a lot of birds. If one red knot steps into the wrong place, the scientists cancel the entire operation. The red knots walking the shore have to be pushed delicately into just the right spot - a process called twinkling.
DUNCAN: Twinkling is skilled, very skilled people, walking the beach slowly in our direction as though they had no intention of scaring a bird or moving it. And the birds just very gently move ahead of the people - feeding all the time, not being interrupted, not leaving the beach and flying off, perhaps, to some other beach, and so that concentrates the birds in the area in front of the cannon net.
TAJ: On the other side of the beach from where Duncan and Niles watch the net, Ben the twinkler, looks like any other relaxed beach stroller - casual, slow - but he’s on a mission. He's the team’s last shot at capturing a group of red knots before they roost for
the day. It seems to be working. A small flock is edging ahead of him toward the net, but when a couple of beachgoers unknowingly approach the operation zone, his attention is diverted and he has to ask them to leave. Larry Niles grips his walkie-talkie, and watches
impatiently from a distance:
NILES ON: Ben we have to act fairly quickly, we only have a short amount of time. [ON
BEN: Roger that! [ON WALKIE-TALKIE]
NILES: We're running out of time quickly, but we still have… we could still make the catch now. You see, if we push them too hard they'll fly.
TAJ: So you're worried?
As I ask this, the red knots that were slowly approaching the net
take flight - scattering into a darkening sky - a flock of lost hope for the day.
LARRY: That’s what I’m worried about.
DUNCAN: Ah, they… they didn't get the battle plans that they needed to land right in front of us.
TAJ: But Charles Duncan and Larry Niles aren’t discouraged for long. They plan the next day’s work, and chat about the tags they spotted on some shorebirds — a yellow band for a bird first tagged in Canada, an orange one for Argentina. If these shorebirds have taught them anything - it’s endurance. For Living on Earth, I’m Mitra Taj.
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