Where I now live, in Bloomington, Indiana, far from any ocean, my year is punctuated by the departure and return of the Canada geese. As the tasks invented by life in middle age accumulate, the rough cries of those geese in the spring and fall—their “ya-honk” of which Walt Whitman spoke—will have to do as my occasional reminder that there’s more to the world than this small college town.
About an hour or two from here, though, in the Goose Pond Fish and Wildlife Area, shorebirds from far-flung places are now regular visitors. This spring, the first black-tailed godwit showed up in nearby Oatsville—a sight bordering on the miraculous in a state that, apart from a slice of Lake Michigan, doesn’t have a coastline. But how on earth did this bird get from Iceland, or central Russia, to Indiana?
The migrations of birds were a cause of wonder to the earliest observers of nature and gave rise to many stories remarkable mainly for their ludicrousness. Birds were said to spend their winters hidden in holes, where they would bide their time until the spring, or to dig themselves deep into the mud under lakes. Some surmised that certain species would simply morph during the cold months, so that the redstart, for example, would re-emerge as a robin.
As naturalists began to study birds more systematically, the mystery of migration only deepened: “Whence they come, and where they breed, is to me unknown,” complained Mark Catesby, author of the earliest comprehensive description of the New World, about the blue herons he saw. Today, we know so much more, but the wonder remains.
Take the red knot, a plump, short-legged, medium-sized sandpiper equipped with an archaic-looking serrated bill good for holding on to slippery food. Red knots have been around for much longer than human beings, perhaps even for as long as 16 million years. And while they did not leave a fossil trail, we know that they adjusted when the planet last donned its deadly skullcap of ice, as Alexander von Humboldt called it.
The red knot is not an elegant bird, by any means, but its somewhat unathletic appearance belies the bird’s capacity for extensive travel. Each year, red knots travel more than 9,000 miles from the “bottom of the world” to their arctic nesting grounds. John James Audubon knew almost nothing about the bird, except that it made for good eating—a fact that, at least by some accounts, also gave the bird its memorable name. Red knots were alleged to have been the favorite food of the Viking king Canute, or Cnut the Great, ruler of the North Sea Empire.
In the spring, these birds, having begun their annual voyage from their winter residences in Latin America, descend on the beaches of South Carolina, Delaware, and New Jersey, and they once did so in such numbers that people felt that they had stepped into some avian fairyland. Over 30 years ago, naturalist Pete Dunne counted as many as 95,000 red knots on the shores of Delaware Bay.
Deborah Cramer, during her recent visit to that same bay, saw (according to the estimate given by the bird conservationist who accompanied her) around 4,000, a catastrophic loss. The subspecies of the red knot that is the subject of this volume—Calidris canutus rufa—is now considered “federally threatened.” What happened?
In this haunting, unusual book, Cramer, author of the well-received Great Waters (2001), a “biography” of the Atlantic Ocean, weaves a complex (and, as I am tempted to pun, knotted) tale about this bird. Guided by biologists, environmentalists, fishermen, and hunters, she follows the knot along its migratory path, gathering what facts she can to show how deeply connected we are to it.
She begins her story in Tierra del Fuego, Chile, but the heart of The Narrow Edge is the chapter set in Delaware Bay, where the lives of the red knots intersect with ours—and they do so through another animal, one that is even more ancient than the knot: the horseshoe crab.
Each spring and early summer, these crabs arrive on the beach en masse to lay their eggs, about 4,000 per square yard. They were once so plentiful that some beaches had as many as 500,000 eggs per square yard. Their eggs are a delicacy to the red knots, a source of the fat they need to sustain themselves during the arduous next leg of their trek. But these crabs also matter to our own survival—not so much as food (though fishermen use them as bait in eel pots), but as biomedical testing devices: The blood of crabs coagulates around toxins harmful to us.