Describes the 20,000-mile annual migration of a shorebird called a Red knot, from the tip of South America to the Arctic tundra nesting grounds and back.

Thousands of ravenous tiny shorebirds race along the water’s edge of Delaware Bay, feasting on pin-sized horseshoe-crab eggs. Fueled by millions of eggs, the migrating red knots fly on. When they arrive at last in their arctic breeding grounds, they will have completed a near-miraculous 9,000-mile journey that began in Tierra del Fuego. Deborah Cramer followed these knots, whose numbers have declined by 75 percent, on their extraordinary odyssey from one end of the earth to the other—from an isolated beach at the tip of South America all the way to the icy tundra. In her firsthand account, she explores how diminishing a single stopover can compromise the birds' entire journey, and how the loss of horseshoe crabs—ancient animals that come ashore but once a year—threatens not only the survival of red knots but also human well-being: the unparalleled ability of horseshoe-crab blood to detect harmful bacteria in vaccines, medical devices, and intravenous drugs safeguards human health. Cramer offers unique insight into how, on an increasingly fragile and congested shore, the lives of red knots, horseshoe crabs, and humans are intertwined. She eloquently portrays the tenacity of small birds and the courage of many people who, bird by bird and beach by beach, keep red knots flying.

B95 can feel it: a stirring in his bones and feathers. It's time. Today is the day he will once again cast himself into the air, spiral upward into the clouds, and bank into the wind. He wears a black band on his lower right leg and an orange flag on his upper left, bearing the laser inscription B95. Scientists call him the Moonbird because, in the course of his astoundingly long lifetime, this gritty, four-ounce marathoner has flown the distance to the moon—and halfway back! B95 is a robin-sized shorebird, a red knot of the subspecies rufa. Each February he joins a flock that lifts off from Tierra del Fuego, headed for breeding grounds in the Canadian Arctic, nine thousand miles away. Late in the summer, he begins the return journey. B95 can fly for days without eating or sleeping, but eventually he must descend to refuel and rest. However, recent changes at ancient refueling stations along his migratory circuit—changes caused mostly by human activity—have reduced the food available and made it harder for the birds to reach. And so, since 1995, when B95 was first captured and banded, the worldwide rufa population has collapsed by nearly 80 percent. Most perish somewhere along the great hemispheric circuit, but the Moonbird wings on. He has been seen as recently as November 2011, which makes him nearly twenty years old. Shaking their heads, scientists ask themselves: How can this one bird make it year after year when so many others fall? National Book Award–winning author Phillip Hoose takes us around the hemisphere with the world's most celebrated shorebird, showing the obstacles rufa red knots face, introducing a worldwide team of scientists and conservationists trying to save them, and offering insights about what we can do to help shorebirds before it's too late. With inspiring prose, thorough research, and stirring images, Hoose explores the tragedy of extinction through the triumph of a single bird. Moonbird is one The Washington Post's Best Kids Books of 2012. A Common Core Title.

A beautifully illustrated book following the extraordinary 18,000-mile annual migration of the Red Knot.

Knots are familiar objects. Yet the mathematical theory of knots quickly leads to deep results in topology and geometry. This work offers an introduction to this theory, starting with our understanding of knots. It presents the applications of knot theory to modern chemistry, biology and physics.