LINDA WERTHEIMER, HOST:
Every year, tens of thousands of shore birds called red knots make an enormous journey. They travel nearly the entire span between the South Pole and the North Pole. But changes in climate along the birds' route are putting the species at risk, so much so that the federal government believes this remarkable bird is threatened with extinction.
NPR's Elizabeth Shogren explains why.
ELIZABETH SHOGREN, BYLINE: Every year, thousands of red knots stop at beaches along the Delaware Bay to feed as they fly north. A crew of biologists, led by Kevin Kalasz, has set a trap for them.
KEVIN KALASZ: Three, two, one - fire.
SHOGREN: Explosives launch a huge net. It falls on of hundreds of birds and traps them. About a dozen people pop out of hiding places in a marsh and dash to collect the birds.
UNIDENTIFIED WOMAN: Do you have a knot box? They're moaning - (imitating birds). They sound so pitiful.
SHOGREN: These biologists and volunteers are catching the birds to monitor their health. Red knot numbers are down by about three quarters since the 1980s. These birds are on their way to the Arctic from the bottom of South America - 9,300 miles. They stop here because they're starving. Kalasz holds a robin-sized bird with a long bill and cinnamon-colored breast.
KALASZ: So this red knot - very skinny. I can feel almost its entire breastbone. Feel right there.
SHOGREN: Oh, my goodness. It's so skinny. There's no meat on its bones.
KALASZ: There's no meat. Yeah.
SHOGREN: They come here because this is where a strange, prehistoric-looking animal called the horseshoe crab comes to lay its eggs. More spawn here than anywhere else in the world.
KALASZ: I mean, there isn't anything better for these birds to eat. These little tiny horseshoe crab eggs are just packed full of fat.
SHOGREN: The red knots' migration is an exquisitely timed act of nature. The crabs and the birds have to arrive at the same time, if the birds are going to get enough to eat. But biologists worry a changing climate could throw this rendezvous out of sync. Warming water temperatures could trigger the crabs to lay eggs before the birds arrive. What's more, rising seas and bigger storms are washing away the beaches. And Wendy Walsh from the U.S. Fish and Wildlife Service says the danger doesn't stop here.
WENDY WALSH: Climate change threat to the red knot is one that's throughout its range.
SHOGREN: Including the Arctic, where it nests.
WALSH: Warming in the Arctic we know is proceeding faster than most other parts of the globe.
SHOGREN: The Fish and Wildlife Service can't do much about the Arctic. What it can do is protect the bird along the East Coast, in places, for example, like North Carolina's Outer Banks, a strip of low-lying islands. That's where some of the birds stop or even stay for the winter.
Warren Judge chairs a local county commission on the Outer Banks. He says, the beaches already get closed to protect other rare shorebirds.
JUDGE: The red knot is just another bird that can land someplace and create another closure. Our tourism is based upon the beach. It's very hard on the economy.
SHOGREN: He says, every time they close a beach, they're closing a great place to fish, surf or play. The Fish and Wildlife Service's Wendy Walsh says, it's true. If the red knot goes on the endangered species list, beaches could be closed briefly every year, and that's not all. Her agency could discourage communities from doing things such as building sea walls.
WALSH: This is totally understandable why humans would do this, when they have valuable infrastructure and property and lives at stake behind the walls, but that is a threat to the red knot going forward.
SHOGREN: Biologists say other animals, from polar bears to butterflies, face similar dilemmas. Climate change is altering their environment.
The government is expected to act on the red knot in late September. That's when the birds will be making their fall migration from the top of the globe back to the bottom.
Elizabeth Shogren, NPR News.
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